An optical-based multipoint 3-axis pressure sensor with a flexible thin-film form - Haoyang Wang, Wenqing Wang, Jae Joon Kim, Chunya Wang, Yan Wang, Binghao Wang, Sunghoon Lee, Tomoyuki Yokota, Takao Someya (Science Advances, 2023)
Multipoint 3-axis tactile pressure sensing by a high-resolution and sensitive optical system provides rich information on surface pressure distribution and plays an important role in a variety of human interaction–related and robotics applications. However, the optical system usually has a bulky profile, which brings difficulties to sensor mounting and system integration. Here, we show a construction of thin-film and flexible multipoint 3-axis pressure sensor by optical methods. The sensor can detect the distribution of 3-axis pressure on an area of 3 centimeter by 4 centimeter, with a high-accuracy normal and tangential pressure sensing up to 360 and 100 kilopascal, respectively. A porous rubber is used as a 3-axis pressure-sensitive optical modulator to omit the thick and rigid focusing system without sacrificing the sensitivity. In addition, by integrating thin and flexible backlight and imager, the sensor has a total thickness of 1.5 milimeter, making it function properly e ven when bent to a radius of 18 milimeter.

Conductive, water-retaining and knittable hydrogel fiber from xanthan gum and aniline tetramer modified-polysaccharide for strain and pressure sensors - Yaqi Zhang, Ruquan Zhang, Yongzhen Tao (Carbohydrate Polymers, 2023)

Rationally designed cellulose hydrogel for an ultrasensitive pressure sensor - Minzhang Chen, Huixiong Wan, Yang Hu, Fengyan Zhao, Xiaoni An, Ang Lu (Materials Horizons, 2023)
Design and regulation of cellulose hydrogel for boosting sensitivity at the micron and nano levels.

A flexible pressure sensor with highly customizable sensitivity and linearity via positive design of microhierarchical structures with a hyperelastic model - Zhenjin Xu, Dezhi Wu, Zhiwen Chen, Zhongbao Wang, Cong Cao, Xiangyu Shao, Gang Zhou, Shaohua Zhang, Lingyun Wang, Daoheng Sun (Microsystems & Nanoengineering, 2023)
Abstract The tactile pressure sensor is of great significance in flexible electronics, but sensitivity customization over the required working range with high linearity still remains a critical challenge. Despite numerous efforts to achieve high sensitivity and a wide working range, most sensitive microstructures tend to be obtained only by inverting naturally existing templates without rational design based on fundamental contact principles or models for piezoresistive pressure sensors. Here, a positive design strategy with a hyperelastic model and a Hertzian contact model for comparison was proposed to develop a flexible pressure sensor with highly customizable linear sensitivity and linearity, in which the microstructure distribution was precalculated according to the desired requirement prior to fabrication. As a proof of concept, three flexible pressure sensors exhibited sensitivities of 0.7, 1.0, and 1.3 kPa − 1</jats:s up> over a linear region of up to 200 kPa, with a low sensitivity error (<5%) and high linearity (~0.99), as expected. Based on the superior electromechanical performance of these sensors, potential applications in physiological signal recognition are demonstrated as well, and such a strategy could shed more light on demand-oriented scenarios, including designable working ranges and linear sensitivity for next-generation wearable devices.

3D-printing-assisted flexible pressure sensor with a concentric circle pattern and high sensitivity for health monitoring - Jihun Lee, Hongyun So (Microsystems & Nanoengineering, 2023)
Abstract In this study, a flexible pressure sensor is fabricated using polydimethylsiloxane (PDMS) with a concentric circle pattern (CCP) obtained through a fused deposition modeling (FDM)-type three-dimensional (3D) printer and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the active layer. Through layer-by-layer additive manufacturing, the CCP surface is generated from a thin cone model with a rough surface by the FDM-type 3D printer. A novel compression method is employed to convert the cone shape into a planar microstructure above the glass transition temperature of a polylactic acid (PLA) filament. To endow the CCP surface with conductivity, PDMS is used to replicate the compressed PLA, and PEDOT:PSS is coated by drop-casting. The size of the CCP is controlled by changing the printing layer height (PLH), which is one of the 3D printing parameters. The sensitivity increases as the PLH increases, and the pressure sensor with a 0.16 mm PLH exhibits outstanding sensitivity (160 kPa −1 ), corresponding to a linear pressure range of 0–0.577 kPa with a good linearity of R 2 = 0.978, compared to other PLHs. This pressure sensor exhibits stable and repeatable operation under various pressures and durability under 6.56 kPa for 4000 cycles. Finally, monitoring of various health signals such as those for the wrist pulse, swallowing, and pronunciation of words is demonstrated as an application. These results support the simple fabrication of a highly sensitive, flexible pressure sensor for human health monitoring.

MXene/PPy@PDMS sponge-based flexible pressure sensor for human posture recognition with the assistance of a convolutional neural network in deep learning - Hui Xia, Lin Wang, Hao Zhang, Zihu Wang, Liang Zhu, Haolin Cai, Yanhua Ma, Zhe Yang, Dongzhi Zhang (Microsystems & Nanoengineering, 2023)
Abstract The combination of flexible sensors and deep learning has attracted much attention as an efficient method for the recognition of human postures. In this paper, an in situ polymerized MXene/polypyrrole (PPy) composite is dip-coated on a polydimethylsiloxane (PDMS) sponge to fabricate an MXene/PPy@PDMS (MPP) piezoresistive sensor. The sponge sensor achieves ultrahigh sensitivity (6.8925 kPa −1 ) at 0–15 kPa, a short response/recovery time (100/110 ms), excellent stability (5000 cycles) and wash resistance. The synergistic effect of PPy and MXene improves the performance of the composite materials and facilitates the transfer of electrons, making the MPP sponge at least five times more sensitive than sponges based on each of the individual single materials. The large-area conductive network allows the MPP sensor to maintain excellent electrical performance over a large-scale pressure range. The MPP sensor can detect a variety of human body activity signals, such as radial artery pulse and different joint movements. The detection and analysis of human motion data, which is assisted by convolutional neural network (CNN) deep learning algorithms, enable the recognition and judgment of 16 types of human postures. The MXene/PPy flexible pressure sensor based on a PDMS sponge has broad application prospects in human motion detection, intelligent sensing and wearable devices.

Design of PDMS/CNT flexible pressure sensor based on double structure with the regulation of electrical properties - Shixue He, Jian Wu, Benlong Su, Shouyao Liu, Youshan Wang (Composites Science and Technology, 2023)

Ultra-sensitive flexible pressure sensor with hierarchical structural laser-induced carbon nanosheets/carbon nanotubes composite film - Xuanqi Guo, Yunfan Li, Ziran Zeng, Yilin Zhao, Xiao Lei, Yaoyu Wang, Dingyi Guo, Feng Liu (Composites Science and Technology, 2023)

Multilayer Perceptron Algorithm-Assisted Flexible Piezoresistive PDMS/Chitosan/cMWCNT Sponge Pressure Sensor for Sedentary Healthcare Monitoring - He Yu, Yubing Liu, Guanya Zhou, Mugen Peng (ACS Sensors, 2023)

Self-strengthening and conductive cellulose composite hydrogel for high sensitivity strain sensor and flexible triboelectric nanogenerator - Wenqing Sun, Xinyu Liu, Wenhui Hua, Shan Wang, Shaojun Wang, Juan Yu, Jifu Wang, Qiang Yong, Fuxiang Chu, Chuanwei Lu (International Journal of Biological Macromolecules, 2023)

Single-Electrode Triboelectric Nanogenerators Based on Ionic Conductive Hydrogel for Mechanical Energy Harvester and Smart Touch Sensor Applications - Harishkumarreddy Patnam, Sontyana Adonijah Graham, Punnarao Manchi, Mandar Vasant Paranjape, Jae Su Yu (ACS Applied Materials & Interfaces, 2023)

Sensitive piezoresistive pressure sensor based on micropyramid patterned tough hydrogel - Yun Xia Zhang, Yuan He, Yi Liang, Jie Tang, Yang Yang, He Ming Song, Miklós Zrínyi, Yong Mei Chen (Applied Surface Science, 2023)

Flexible multisensory sensor based on hierarchically porous ionic liquids/thermoplastic polyurethane composites - Meiling Peng, Xiang Li, Yinfeng Liu, Jianwen Chen, Xiaohua Chang, Yutian Zhu (Applied Surface Science, 2023)

A low-cost hydrogel with high conductivity and flexibility for pressure sensor and supercapacitor - Lingxiao Zhou, Qing Xin, Jun Lin, Shangqing Liang, Guoqing Yang (Applied Materials Today, 2023)

High‐Performance MXene‐Based Flexible and Wearable Pressure Sensor Based on a Micro‐Pyramid Structured Active Layer - Xiaohui Fang, Lizhen Min, Zhen Qin, Shun Gong, Biao Zhao, Yuhuan Lv, Kai Pan (Advanced Materials Technologies, 2023)
Abstract With the advent of smart era, constructing high‐quality flexible electronic devices is urgently demanded. In this contribution, a flexible and wearable pressure sensor with high stability is tactfully designed and prepared based on pyramid‐like MXene film. The investigated pyramid‐like MXene film is fabricated by a simple and low‐cost substrate shrinkage method. Owing to the conical pyramid structure, the resulting pressure sensor can output continuous and stable electrical signal under stress, and has good cycling stability and long working life (18 000 cycles). Specifically, the sensitivity of the sensor can reach up to 64.56 kPa −1 under small stress, and the sensing range is 4.9 Pa–98 kPa. Moreover, the response and recovery time under small stress is 59 and 15 ms, respectively. The sensing mechanism of the pressure sensor is explored. The prepared flexible wearable sensor shows great application potential in human motion and health monitoring.

The flexible and distributed pressure sensor with 64 units for on-line gait recognition analysis - Fuzheng Zhang, Xiangyue Xu, Qijing Lin, Dan Xian, Kun Yao, Na Zhao, Libo Zhao, Zhuangde Jiang (Measurement, 2023)

Negative pressure-assisted porous structure with gradient dielectrics design for linearity enhancement of flexible capacitance pressure sensor - Yan Zhong, Longgang Wu, Fucheng Gu, Jiaqi Wang, Shengping Dai, Hao Zhu, Guanggui Cheng, Jianning Ding (Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2023)

All-organic sandwich structured polymer dielectrics with polyimide and PVDF for high temperature capacitor application - Shiqi Yu, Yuan Liu, Cuilian Ding, Xuan Liu, Yang Liu, Dang Wu, Hang Luo, Sheng Chen (Journal of Energy Storage, 2023)

Compatible composite electrolyte membrane Li7La3Zr2O12/SB-PVDF for solid-state lithium ion battery - Hongying Hou, Baoxiang Huang, Xiaohua Yu, Jian Lan, Sen Ming, Ju Rong, Xianxi Liu, Fangshu Chen (Journal of Energy Storage, 2023)

Flexible free standing electrodes based on laser-irradiated PVC/PVDF/AuNPs for the development of high performance supercapacitor electrodes - Sherief A. Al Kiey, A.A. Menazea, A.M. Ismail (Journal of Energy Storage, 2023)

Exceptional cyclability of thermally stable PVdF-co-HFP/SiO2 nanocomposite polymer electrolytes for sodium ion batteries - Akhila Das, Amrutha Melepurakkal, Pranav Sreeram, K.T. Gireesh, Neethu T.M. Balakrishnan, M.J. Jabeen Fatima, Abhilash Pullanchiyodan, Jou-Hyeon Ahn, Manjusha V. Shelke, Prasanth Raghavan (Journal of Energy Storage, 2023)

Defect Dipole‐Induced Fatigue Strain Recoverability in Lead‐Free Piezoelectric Ceramics - Binquan Wang, Geng Huangfu, Jie Wang, Hua Li, Yiping Guo (Advanced Functional Materials, 2023)
Abstract Piezoelectric ceramics have garnered extensive utilization in high‐precision actuators, where the magnitude of electric field‐induced strain and fatigue resistance play crucial roles in actuation applications. Herein, an innovative strategy based on defect dipoles is proposed to form a defect‐engineered polymorphic phase transition and achieve a giant piezoelectric strain coefficient of 3080 pm V −1 in Li/Sr‐doped (K 0.5 Na 0.5 )NbO 3 lead‐free piezoceramics. The mechanism responsible for the enhanced strain performance lies in the optimized strain compatibility between the refined stripe domains and the nanosized domains. Additionally, the results demonstrate that the material is able to recover from fatigue‐induced strain depletion under the stimulation of bipolar electric fields. This property can be phenomenologically explained by the rigid ion model, in which the application of reversal electric fields can facilitate the restoration of defect dipoles, thereby greatly contributing to strain recoverability. This study establishes a close correlation between the unipolar strain properties and the inherent flexibility of defect dipoles and provides new insight into the design of high‐reliability, large‐stroke piezoceramics.

Kirigami–Origami‐Inspired Lead‐Free Piezoelectric Ceramics - Zehuan Wang, Denghao Ma, Yunhan Wang, Yan Xie, Zhonghui Yu, Jin Cheng, Li Li, Liang Sun, Shuxiang Dong, Hong Wang (Advanced Science, 2023)
Abstract Kirigami‐ and oirigami‐inspired techniques have emerged as effective strategies for material structure design; however, the use of these techniques is usually limited to soft and deformable materials. Piezoelectric ceramics, which are typical functional ceramics, are widely used in electronic and energy devices; however, the processing options for piezoelectric ceramics are limited by their brittleness and feedstock viscosity. Here, a design strategy is proposed for the preparation of lead‐free piezoelectric ceramics inspired by kirigami/origami. This strategy involves direct writing printing and control over the external gravity during the calcination process for the preparation of curved and porous piezoelectric ceramics with specific shapes. The sintered BaTiO 3 ceramics with curved geometries produced using this strategy exhibit a high piezoelectric constant ( d 33 = 275 pC N< jats:sup>−1 ), which is 45% higher than that of conventionally sintered sheet ceramics. The curved structure of the ceramics is well‐suited for use in the human body and it was determined that these curved ceramics can detect pulse signals. This strategy can be applied in the large‐scale and low‐cost production of other piezoelectric ceramics with various curved shapes and provides a new approach for the preparation of complex‐shaped ceramics.

Enhanced Piezoelectric, Ferroelectric, and Electrostrictive Properties of Lead‐Free (1‐x)BCZT‐(x)BCST Electroceramics with Energy Harvesting Capability - Bharat G. Baraskar, Yesappa D. Kolekar, Balu. R. Thombare, Ajit. R. James, Rahul C. Kambale, C. V. Ramana (Small, 2023)
Abstract Next‐generation electronics and energy technologies can now be developed as a result of the design, discovery, and development of novel, environmental friendly lead (Pb)‐free ferroelectric materials with improved characteristics and performance. However, there have only been a few reports of such complex materials’ design with multi‐phase interfacial chemistry, which can facilitate enhanced properties and performance. In this context, herein, novel lead‐free piezoelectric materials (1‐ x )Ba 0.95 Ca 0.05 Ti 0.95 Zr 0.05 O 3 ‐( x )Ba 0.95 Ca 0.05 Ti 0.95 Sn 0.05 O 3 , are reported, which are represented as (1‐ x )BCZT‐( x )BCST, with demonstrated excellent prope rties and energy harvesting performance. The (1‐ x )BCZT‐( x )BCST materials are synthesized by high‐temperature solid‐state ceramic reaction method by varying x in the full range ( x = 0.00–1.00). In‐depth exploration research is performed on the structural, dielectric, ferroelectric, and electro‐mechanical properties of (1‐ x )BCZT‐( x )BCST ceramics. The formation of perovskite structure for all ceramics without the presence of any impurity phases is confirmed by X‐ray diffraction (XRD) analyses, which also reveals that the Ca 2+ , Zr 4+ , and Sn 4+ are well dispersed within the BaTiO 3 lattice.

Investigation of BiFeO3-BaTiO3 lead-free piezoelectric ceramics with nonstoichiometric bismuth - Hailan Qin, Jianwei Zhao, Xiaoxin Chen, Hongtian Li, Shenghao Wang, Yuxiao Du, Huanfu Zhou, Peifeng Li, Dawei Wang (Microstructures, 2023)
BiFeO3-BaTiO3 (BF-BT)-based lead-free ceramics are promising piezoelectric materials exhibiting high Curie temperatures and excellent electrochemical properties. In this study, 0.70Bi1+x FeO3-0.30BaTiO3 (B1+x F-BT, x = -0.01, 0.00, 0.01, 0.02, 0.03, 0.04) lead-free piezoelectric ceramics were successfully fabricated via the conventional solid-phase reaction process. Crystallographic structure, microstructure, dielectric, impedance, ferroelectric, and piezoelectric properties among different compositions were comprehensively investigated. The X-ray diffraction analysis confirmed that all compositions exhibited a typical perovskite structure with a cubic-rhombohedral phase mixture. The grain size of ceramics tends to increase as the Bi2O3 content rises. In particular, the backscattered electron images and energy dispersive analysis revealed prominent core-shell microstructure within grains. Notably, the BF-BT ceramic containing 1% excess Bi displayed the maximum d 33 ~217 pC/N an d ~243 pm/V accompanied by a high Curie temperature of 515 °C. The findings demonstrate the potential feasibility of BF-BT ceramics in the field of lead-free piezoelectric ceramics.

3D printing of doped barium-titanate using robocasting - Toward new generation lead-free piezoceramic transducers - Rebecca Damamme, Laurence Seveyrat, Ana Borta-Boyon, Van-Cuong Nguyen, Minh-Quyen Le, Pierre-Jean Cottinet (Journal of the European Ceramic Society, 2023)

Temperature effect on elastic and fracture behaviour of lead-free piezoceramic BaTiO3 - Zdeněk Chlup, Daniel Drdlík, Hynek Hadraba, Oldřich Ševeček, Filip Šiška, Jiří Erhart, Karel Maca (Journal of the European Ceramic Society, 2023)

Evaluation of phase and domain switching in Sn-doped BCZT piezoceramics with coexisting ferroelectric phases - Abhijit Pramanick, Laurent Daniel, Sarangi Venkateshwarlu, Valentin Segouin, Yang Ren (Journal of the European Ceramic Society, 2023)

Synergy of morphotropic phase boundary and internal bias fields to achieve high d33 and d33* simultaneously in lead-free BNT-based ceramics - Dongyan Yu, Changrong Zhou, Jun Chen, Qingning Li, Guanghui Rao, Changlai Yuan, Jiwen Xu (Ceramics International, 2023)

Enhanced non-layer-dependent piezo-response in sailboat-like vertical molybdenum disulfide nanosheets for piezo-catalytic hydrogen evolution and dye degradation: Effect of microstructure and phase composition - Yimeng Wang, Hecheng Ma, Jianjun Liu, Ziang Zhang, Yingchun Yu, Shengli Zuo (Journal of Colloid and Interface Science, 2023)

Nanosphere-structured hierarchically porous PVDF-HFP fabric for passive daytime radiative cooling via one-step water vapor-induced phase separation - Ningbo Cheng, Dongyang Miao, Chao Wang, Yanyan Lin, Aijaz Ahmed Babar, Xianfeng Wang, Zhaohui Wang, Jianyong Yu, Bin Ding (Chemical Engineering Journal, 2023)

Hierarchically structural TiO2-PVDF fiber film with particle-enhanced spectral performance for radiative sky cooling - Na Li, Limin Wei, Mingzhu You, Meiting Chen, Huijuan Li, Huijian Liu, Zheng Fang, Haifeng Bao (Solar Energy, 2023)

A self-actuated electrocaloric polymer heat pump design exploiting the synergy of electrocaloric effect and electrostriction - Xin Chen, Wenyi Zhu, Alexander S Rattner, Q M Zhang (Journal of Physics: Energy, 2023)
Abstract Caloric cooling is an attractive family of technologies owing to their environmental friendliness and potential for higher efficiency than present refrigeration systems. Cooling devices based on the electrocaloric (EC) effect specifically have the added benefit of being easily miniaturized, enabling applications in electronic thermal management, wearables and localized cooling. A challenge in prior compact EC cooling devices has been the need for a separate actuation mechanism to cyclically contact the EC material with hot and cold interfaces. Here, we propose a self-actuated EC polymer heat pump, exploiting recent discoveries of giant EC and electromechanical responses under low electric fields in P(VDF-TrFE-CFE-FA) (VDF: vinylidene fluoride, TrFE: trifluoroethylene, CFE: chlorofluoroethylene, FA: fluorinated alkynes) relaxor tetrapolymers. We show that the transverse electroactuation of P(VDF-TrFE-CFE-FA) relaxor tetrapolymer films can be tai lored over a broad range, from strong actuation to weak actuation, without affecting the high EC response. Using this principle, a unimorph actuator was constructed from two EC tetrapolymer layers with large differences in electroactuation. This device autonomously achieves a large displacement between the heating and cooling cycles of the EC films, which could be used to switch thermal contact between hot and cold interfaces. This concept could thus enable highly efficient and compact EC heat pumps.

Ultra‐Emissive MgO‐PVDF Polymer Nanocomposite Paint for Passive Daytime Radiative Cooling - Prasanna Das, Sourav Rudra, Krishna Chand Maurya, Bivas Saha (Advanced Materials Technologies, 2023)
Abstract Passive daytime radiative cooling (PDRC) holds enormous potential to provide low‐cost, electricity‐free cooling in hot environments and to overcome the urban heat island effects. Conventional radiative cooling devices consist of complicated multilayer structure, and reflective back metallic plates that are unsuitable for household applications. Most single‐layer polymer nanocomposites are also not practically applicable due to their high cost, frailty, and sub‐optimum cooling performances arising from low thermal emissivity. Herein, it is shown that ultra‐white and ultra‐emissive magnesium oxide (MgO)‐polyvinylidene fluoride (PVDF) nanocomposite that exhibits an average ≈7°C temperature decrease below the sub‐ambient conditions under direct sunlight. The optimized MgO‐PVDF metamaterials with a dielectric particle size of ≈50 nm exhibit a large solar reflectance of 96.3% due to the Mie‐scattering and a record high thermal emission of 98.5% at the atmospheric transmission window due to the anharmonic multiphonon Mg─O bond vibrations, and other stretching/bonding vibrations from the polymer. The nanocomposite paint exhibits water‐resistant hydrophobic properties and can be easily coated on pavers, wood sticks, etc., with high uniformity and good adhesion. This work provides a low‐cost, scalable, and solution‐processed nanocomposite coating with excellent cooling performance for pavers, tiles, and building cooling applications, especially in equatorial regions, southeast Asia, middle‐east, and African regions.

Preparation of 3D BN-BT/PVDF skeleton structure composites for high thermal conductivity and energy storage - Lizhu Guan, Xuemin Zhao, Zengren Ji, Mengyuan Jiang, Yongai Cui, Ling Weng, Xuan Wang, Junwang Liu (Polymer Testing, 2023)

Enhanced electrocaloric effect of P(VDF-TrFE)-based nanocomposites with Ca and Sn co-doped BaTiO3 particles - Melike Tokkan, Mustafa M. Demir, Umut Adem (Ceramics International, 2023)

Positive and Negative Electrocaloric Effect in soft- and hard-doped commercial PZT ceramics - Magdalena Krupska-Klimczak, Irena Jankowska-Sumara, Sylwia Sowa (Ceramics International, 2023)

Electrolyte design for lithium-ion batteries with a cobalt-free cathode and silicon oxide anode - Seongjae Ko, Xiao Han, Tatau Shimada, Norio Takenaka, Yuki Yamada, Atsuo Yamada (Nature Sustainability, 2023)
Abstract Lithium-ion batteries (LIBs) to power electric vehicles play an increasingly important role in the transition to a carbon neutral transportation system. However, at present the chemistry of LIBs requires, among other elements, cobalt (Co), which will probably become scarce over time in addition to posing supply chain risks related to its single source, human rights and mining practices. To address this problem, we construct a LIB pairing a Co-free cathode with a silicon suboxide (SiO x ) anode that possesses a high cut-off voltage of 4.9 V and sustains unprecedented 1,000 cycles. Underlying this favourable electrode combination is a rational electrolyte design based on 3.4 M LiFSI/FEMC featuring a shifted potential, which serves to aid formation of robust passivation layers on the anode and promote electrolyte stability against both reductive and oxidative degradations. Our electrolyte formulation offers a pathway towards both sustainable and high-performing LIBs, while the co ncept could be applied to other electrochemical energy technologies.

Dielectric Filler‐Induced Hybrid Interphase Enabling Robust Solid‐State Li Metal Batteries at High Areal Capacity - Xufei An, Yang Liu, Ke Yang, Jinshuo Mi, Jiabin Ma, Danfeng Zhang, Likun Chen, Xiaotong Liu, Shaoke Guo, Yuhang Li, Yuetao Ma, Ming Liu, Yan‐Bing He, Feiyu Kang (Advanced Materials, 2023)
Abstract The fillers in composite solid‐state electrolyte are mainly responsible for the enhancement of the conduction of Li ions but barely regulate the formation of solid electrolyte interphase (SEI). Herein, a unique filler of dielectric NaNbO 3 for the poly(vinylidene fluoride) (PVDF)‐based polymer electrolyte, which is subjected to the exchange of Li + and Na + during cycling, is reported and the substituted Na + is engaged in the construction of a fluorinated Li/Na hybrid SEI with high Young's modulus, facilitating the fast transport of Li + at the interface at a high areal capacity and suppressing the Li dendrite growth. The dielectric NaNbO 3 also induces the generation of high‐dielectric β phase of PVDF to promote the dissociation of Li salt. The Li/Li symmetrical cell exhibits a long‐term dendrite‐free cycling over 600 h at a high areal capacity of 3 mA h cm −2 . The LiNi 0.8 Mn 0.1 Co 0.1 O 2 /Li solid‐state cells with NaNbO 3 stably cycle 2200 times at 2 C and that paired w ith high‐loading cathode (10 mg cm −2 ) can stably cycle for 150 times and exhibit excellent performances at −20 °C. This work provides a novel design principle of fillers undertaking interfacial engineering in composite solid‐state electrolytes for developing the safe and stable solid‐state lithium metal battery.

Physicochemical Dual Cross‐Linking Conductive Polymeric Networks Combining High Strength and High Toughness Enable Stable Operation of Silicon Microparticle Anodes - Biao Zhang, Yanling Dong, Jingrui Han, Yunjing Zhen, Chuangang Hu, Dong Liu (Advanced Materials, 2023)
Abstract The poor interfacial stability and insufficient cycling performance caused by undesirable stress hinder the commercial application of silicon microparticles (µSi) as next‐generation anode materials for high‐energy‐density lithium‐ion batteries. Herein, a conceptionally novel physicochemical dual cross‐linking conductive polymeric network is designed combining high strength and high toughness by coupling the stiffness of poly(acrylic acid) and the softness of carboxyl nitrile rubber, which includes multiple H‐bonds, by introducing highly branched tannic acid as a physical cross‐linker. Such a design enables effective stress dissipation by folded molecular chains slipping and sequential cleavage of H‐bonds, thus stabilizing the electrode interface and enhancing cycle stability. As expected, the resultant electrode (µSi/PTBR) delivers an unprecedented high capacity retention of ≈97% from 2027.9 mAh g −1 at the 19th to 1968.0 mAh g −1 at the 200th cycle at 2 A g −1 . Meanwhile, th is unique stress dissipation strategy is also suitable for stabilizing SiO x anodes with a much lower capacity loss of ≈0.012% per cycle over 1000 cycles at 1.5 A g −1 . Atomic force microscopy analysis and finite element simulations reveal the excellent stress‐distribution ability of the physicochemical dual cross‐linking conductive polymeric network. This work provides an efficient energy‐dissipation strategy toward practical high‐capacity anodes for energy‐dense batteries.

Solvent‐Free Ultrafast Construction of Se‐Deficient Heterojunctions of Bimetallic Selenides toward Flexible Sodium‐Ion Full Batteries - Zhonghui Sun, Dongyang Qu, Dongxue Han, Zhen‐Yi Gu, Jin‐Zhi Guo, Xin‐Xin Zhao, Yingming Ma, Bolin Zhao, Zhongqian Song, Xing‐Long Wu, Li Niu (Advanced Materials, 2023)
Abstract Flexible quasi‐solid‐state sodium ion batteries featuring their low‐cost, high safety and excellent mechanical strength have attracted widespread interest in the field of wearable electronic devices. However, the development of such batteries faces great challenges including the construction of interfacial compatible flexible electrode materials and addressing the high safety demands of electrolyte. Here selenium‐vacancies regulated bimetallic selenide heterojunctions anchored on waste cotton cloth‐derived flexible carbon cloth (FCC) with robust interfacial C‐Se‐Co/Fe chemical bonds as a flexible anode material (CCFSF) is proposed by ultrafast microwave pyrolysis method. Rich selenium vacancies and CoSe 2 /FeSe 2−x heterostructures are synchronously formed that can significantly improve ionic and electronic diffusion kinetics. Additionally, a uniform carbon layer coating on the surface of Se‐deficient heterostructures endows it with outstanding structural stability. The flexib le cathode (PB@FCC) is also fabricated by directly growing Prussian blue nanoparticles on the FCC. Furthermore, an advanced flexible quasi‐solid‐state Na‐ion pouch cell is assembled by coupling CCFSF anode, PB@FCC cathode with P(VDF‐HFP)‐based gel polymer electrolyte. The full cell not only demonstrates excellent energy storage performance but also robust mechanical flexibility and safety. The present work offers an effective avenue to achieve high safety flexible energy storage device, promoting the development of flexible wearable electronic devices.

Bilayer Zwitterionic Metal‐Organic Framework for Selective All‐Solid‐State Superionic Conduction in Lithium Metal Batteries - Yuan Ouyang, Wei Gong, Qi Zhang, Jia Wang, Sijia Guo, Yingbo Xiao, Dixiong Li, Changhong Wang, Changhong Wang, Xueliang Sun, Chaoyang Wang, Chaoyang Wang, Shaoming Huang (Advanced Materials, 2023)
Abstract Solid‐state batteries (SSBs) hold immense potential for improved energy density and safety compared to traditional batteries. However, existing solid‐state electrolytes (SSEs) face challenges in meeting the complex operational requirements of SSBs. This study introduces a novel approach to address this issue by developing a metal‐organic framework (MOF) with customized bilayer zwitterionic nanochannels (MOF‐BZN) as high‐performance SSEs. The BZN consist of a rigid anionic MOF channel with chemically grafted soft multicationic oligomers (MCOs) on the pore wall. This design enables selective superionic conduction, with MCOs restricting the movement of anions while coulombic interaction between MCOs and anionic framework promoting the dissociation of Li + . MOF‐BZN exhibits remarkable Li + conductivity (8.76 × 10 −4 S cm −1 ), high Li + transference number (0.75), and a wide electrochemical window of up to 4.9 V at 30 °C. Ultimately, the SSB utilizing flame retarded MOF‐BZN achie ves an impressive specific energy of 419.6 Wh kg anode+cathode+electrolyte −1 under constrained conditions of high cathode loading (20.1 mg cm −2 ) and limited lithium metal source. The constructed bilayer zwitterionic MOFs present a pioneering strategy for developing advanced SSEs for highly efficient SSBs.

A Spidroin‐Inspired Hierarchical‐Structure Binder Achieves Highly Integrated Silicon‐Based Electrodes - Pengzhou Mu, Shu Zhang, Huanrui Zhang, Jiedong Li, Zhi Liu, Shanmu Dong, Guanglei Cui (Advanced Materials, 2023)
As a promising component for next-generation high-energy lithium-ion batteries, silicon-based electrodes have attracted increasing attention by virtue of their ultrahigh theoretical specific capacities. Nevertheless, fast capacity fading posed by tremendous silicon-based electrode volume changes during cycling remains a huge challenge before large-scale applications. In this work, an aqueous-oil binary solution based blend (AOB) binder characterized by a spidroin-like hierarchical structure for tolerating the huge volume changes of silicon-based electrodes is developed. In the AOB binder, the polymer, containing hydrophobic tetrazole groups, denoted as PPB, and the water-soluble amorphous poly(acrylic acid), mimick the β-sheet and α-helix structure of spidroin, respectively. Benefitting from such biomimetic design, the AOB binder enables both high tensile strength and elasticity, and strong electrode adhesion, therefore apparently stabilizing the silicon-based electrode structure and r endering prolonged electrode cycle life. Such a strategy endows 3.3 Ah soft package cells assembled with Si/C composite anode and NCM811 cathode with a discharge specific capacity of 2.92 Ah after 700 cycles. This work marks a milestone in developing state-of-the-art silicon-based electrodes toward high-energy-density lithium-battery applications.

Carrageenan as a Sacrificial Binder for 5 V LiNi0.5Mn1.5O4 Cathodes in Lithium‐Ion Batteries - Barsa Chang, Dae Hui Yun, Insu Hwang, Joon Kyo Seo, Joonhee Kang, Gyeongho Noh, Sunghun Choi, Jang Wook Choi (Advanced Materials, 2023)
Abstract 5 V‐class LiNi 0.5 Mn 1.5 O 4 (LNMO) with its spinel symmetry is a promising cathode material for lithium‐ion batteries. However, the high‐voltage operation of LNMO renders it vulnerable to interfacial degradation involving electrolyte decomposition, which hinders long‐term and high‐rate cycling. Herein, this longstanding challenge presented by LNMO is overcome by incorporating a sacrificial binder, namely, λ‐carrageenan (CRN), a sulfated polysaccharide. This binder not only uniformly covers the LNMO surface via hydrogen bonding and ion‐dipole interaction but also offers an ionically conductive cathode–electrolyte interphase layer containing LiSO x F, a product of the electrochemical decomposition of the sulfate group. Taking advantage of these two auspicious properties, the CRN‐based electrode exhibits cycling and rate performance far superior to that of its counterparts based on the conventional poly(vinylidene difluoride) and sodium alginate binders. This study introduces a new concept, namely “sacrificial” binder, for battery electrodes known to deliver superior electrochemical performance but be adversely affected by interfacial instability.

Rechargeable Zinc–Air versus Lithium–Air Battery: from Fundamental Promises Toward Technological Potentials - Xuanxuan Bi, Yi Jiang, Ruiting Chen, Yuncheng Du, Yun Zheng, Rong Yang, Rongyue Wang, Jiantao Wang, Xin Wang, Zhongwei Chen (Advanced Energy Materials, 2023)
Abstract As battery technologies that can potentially increase the energy density and expand application scenarios of the lithium‐ion batteries, rechargeable metal‒air batteries have attracted extensive research interests. Among a variety types of metal anodes investigated, zinc (Zn)‒air and lithium (Li)‒air batteries hold best prospects for real‐world applications and attract the most scientific community interests. It has been more than 10 years since Cho et al. first compared Li–air and Zn–air batteries, during which great progress has been made. In this review, these two representative metal‒air battery technologies are compared in view of the most recent progresses and improvements in the last decade, especially efforts that push these technologies toward real world applications. It starts with the fundamentals of Zn–air and Li–air batteries, and discusses the progress made in electrolyte design, anode protection, and cathode catalysts development. It ends with an evaluation of th e current research state along with an overall future perspective. Such a comprehensive comparison of typical non‐aqueous and aqueous battery systems with a focus on practical application criteria would be a timely review of metal‒air battery development in the last decade, which shed light for fundamental and applied research, eventually leading to real‐world application.

Prelithiation: A Critical Strategy Towards Practical Application of High‐Energy‐Density Batteries - Hongqiang Zhang, Jun Cheng, Hongbin Liu, Deping Li, Zhen Zeng, Yuanyuan Li, Fengjun Ji, Yixuan Guo, Youri Wei, Shuai Zhang, Tiansheng Bai, Xiao Xu, Ruiqin Peng, Jingyu Lu, Lijie Ci (Advanced Energy Materials, 2023)
Abstract To meet the demand for high‐energy‐density batteries, alloy‐type and conversion‐type anode materials have attracted growing attention due to their high specific capacity. However, the huge irreversible lithium loss during initial cycling significantly reduces the energy density of the full cell, which limits their practical applications. Fortunately, various anode prelithiation techniques have been developed to compensate for the initial lithium loss. At the same time, the cathode prelithiation has been proposed and demonstrated remarkable enhancement in the electrochemical performance, along with excellent scalability and compatibility with the existing battery production processes. Here, recent advances are reviewed in the prelithiation of both anodes and cathodes, and the key challenges are discussed in front of their practical applications. It is aimed to provide better recommendations and assistance for its large‐scale practical applications.

A Supertough and Highly‐Conductive Nano‐Dipole Doped Composite Polymer Electrolyte with Hybrid Li+‐Solvation Microenvironment for Lithium Metal Batteries - Shanshan Lv, Xuewei He, Zhongfeng Ji, Sifan Yang, Lanxiang Feng, Xuewei Fu, Wei Yang, Yu Wang (Advanced Energy Materials, 2023)
Abstract Achieving solid polymer electrolytes with ceramic‐like fast single‐ion conduction behavior, separator‐required mechanical properties, and good lithium‐dendrite suppression capability is essential but extremely challenging for the practical success of solid‐state lithium‐metal batteries. The key to overcome this long‐standing bottleneck is to rationally design the Li + ‐transport microenvironment inside the polymeric ion‐conductors. Herein, the concept of a nano‐dipole doped composite polymer electrolyte (NDCPE) is proposed using surface‐charged halloysite nanotubes (d‐HNTs) as the dopant to achieve a Li + ‐transport‐friendly microenvironment in poly(vinylidene fluoride) (PVDF) based quasi‐solid electrolytes. Results show that the d‐HNTs doping can immobilize the anions and help dissociate the lithium salt, which leads to an advanced dynamic Li + ‐interface yielding both a high Li + ‐transference number (0.75 ± 0.04) and ionic conductivity (0.29 ± 0.04 mS cm −1 @R.T.). Moreover , compared with the commercial separator, the NDCPE thin‐film shows similar toughness, mechanical strength, and puncture resistance, but much superior capability for stabilizing the lithium‐metal anode. To understand the possible doping mechanism, a hybrid Li + ‐solvation model combining the surface charges of the nanofiller, absorbed solvent molecules, and absorbed polymer chain unit is proposed and discussed for guiding the future studies on advanced hybrid solid polymer electrolytes.

The Rational Design of Low‐Barrier Fluorinated Aluminum Substrates for Anode‑Free Sodium Metal Battery - Shengan Wu, Jinkwang Hwang, Kazuhiko Matsumoto, Rika Hagiwara (Advanced Energy Materials, 2023)
Abstract Anode‐free Na metal batteries are acclaimed for their high energy densities achieved through current collectors in situ plated with Na metal in the absence of active negative materials. The advancement of these devices hinges on the development of affordable current collectors for effective Na deposition and the design of advanced electrolytes with suppressed Na metal loss as measured against the poor cycling performance and safety issues associated with traditional organic electrolytes and convectional current collectors. Herein, the authors report a novel strategy for fabricating an Al current collector through annealing and fluorination using hydrofluoric acid to optimize its crystal orientation and surface properties in a bid to establish highly reversible Na deposition/dissolution processes. Through a series of characterization, electrochemical, and computational analyses, it is ascertained that the F‐rich surface of the (100)‐oriented Al substrate provides high‐affinity nucleation sites that initiate and sustain a uniform Na metal deposition and form a propitious solid electrolyte interphase layer. The present anode‐free Na metal battery prototype comprised of the treated Al substrate, a high mass loading Na 3 V 2 (PO 4 ) 3 positive electrode, and an ionic liquid electrolyte achieves a high average Coulombic efficiency (≈98%) over 50 cycles: indeed, groundbreaking performance for uncoated current collectors that do not require activation cycles.

Approaching Microsized Alloy Anodes via Solid Electrolyte Interphase Design for Advanced Rechargeable Batteries - Yuan Tian, Yongling An, Biao Zhang (Advanced Energy Materials, 2023)
Abstract Microsized alloy anodes (Si, P, Sb, Sn, Bi, etc.) with high capacity, proper working potential, high tap density, and low cost are promising for breaking the energy limits of current rechargeable batteries. Nevertheless, they suffer from large volume changes during cycling processes, posing a great challenge in maintaining a thin, dense, and intact solid electrolyte interphase (SEI) layer. Recent progress suggests that the problematic SEI layer can be turned to advantage in maintaining the integrity of microparticle anodes if well designed, which is expected to significantly boost the cyclic stability without resorting to complex electrode architectures. Advances in this attractive direction are reviewed to shed light on future development. First, the key issues of high‐capacity microsized alloy anodes and the fundamentals of the SEI layer are discussed. Thereafter, progress on the regulation strategies of SEI layers in high‐capacity microsized alloy anodes for advanced rechar geable batteries, including electrolyte engineering, electrode surface modification, cycle protocols, and electrode architecture design, are outlined. Finally, potential challenges and perspectives on developing high‐quality SEI layers for microsized alloy anodes are proposed.

Water‐Soluble Inorganic Binders for Lithium‐Ion and Sodium‐Ion Batteries - Shivam Trivedi, Venkat Pamidi, Sebastián Pinto Bautista, Farra Nur Aliah Shamsudin, Marcel Weil, Prabeer Barpanda, Dominic Bresser, Maximilian Fichtner (Advanced Energy Materials, 2023)
Abstract Inorganic materials form an emerging class of water‐soluble binders for battery applications. Their favourable physicochemical properties, such as intrinsic ionic conductivity, high thermal stability (>1000 °C), and compatibility to coat a diverse range of electrode materials make them useful binders for lithium‐ion and sodium‐ion batteries. Li and Na containing phosphates and silicates are attractive choices as multifunctional inorganic aqueous binders (IABs). This review discusses these binders' structural, thermal, and ionic properties, followed by exploiting their ionically conducting nature for all‐solid‐state batteries. Subsequently, the application of these compounds as binders and surface coating agents for different anodes and cathodes in lithium‐ion and sodium‐ion batteries is discussed. Eventually, a first evaluation of their environmental impacts and economic aspects is presented as well.

Striking a Balance: Exploring Optimal Functionalities and Composition of Highly Adhesive and Dispersing Binders for High‐Nickel Cathodes in Lithium‐Ion Batteries - Daun Jeong, Da‐Sol Kwon, Hee Joong Kim, Jimin Shim (Advanced Energy Materials, 2023)
Abstract Nickel‐rich layered oxide, LiNi x Co y Mn z O 2 (NCM, x > 0.8), has emerged as a promising cathode material for lithium‐ion batteries due to its high specific capacity and energy density. However, there remains a challenge regarding NCM degradation during cycling, associated with interfacial side reactions and microcrack formation. Herein, a functional poly(norbornene‐ co ‐norbornene dicarboxylic acid‐ co ‐heptafluorobutyl norbornene imide) (PNCI)‐based binder system is introduced, with controlled functionalities and monomer compositions, to preserve the structural integrity of NCM. The PNCI binder system incorporates three different norbornene‐derived monomers with distinct functionalities, allowing for multifunctionality, including electro‐chemo‐mechanical stability, strong adhesion, and dispersibility. By systematically adjusting the molar composition of the PNCI binders, the overall binder characteristics are fine‐tuned, optimizing the adhesion and dispersion of electro de components. The optimized PNCI binder, with desired adhesion strength, surface energy, and polarity, plays a crucial role in facilitating the formation of a uniform electrode structure with a high areal mass loading of NCM, ensuring long‐term cycling stability. This study highlights the significance of striking a balance between functionalities and composition in binder systems to achieve high‐performance NCM cathodes.

Design of multifunctional polymeric binders in silicon anodes for lithium‐ion batteries - Masytha Nuzula Ramdhiny, Ju‐Won Jeon (Carbon Energy, 2023)
Abstract Silicon (Si) is a promising anode material for lithium‐ion batteries (LIBs) owing to its tremendously high theoretical storage capacity (4200 mAh g −1 ), which has the potential to elevate the energy of LIBs. However, Si anodes exhibit severe volume change during lithiation/delithiation processes, resulting in anode pulverization and delamination with detrimental growth of solid electrolyte interface layers. As a result, the cycling stability of Si anodes is insufficient for commercialization in LIBs. Polymeric binders can play critical roles in Si anodes by affecting their cycling stability, although they occupy a small portion of the electrodes. This review introduces crucial factors influencing polymeric binders' properties and the electrochemical performance of Si anodes. In particular, we emphasize the structure–property relationships of binders in the context of molecular design strategy, functional groups, types of interactions, and functionalities of binders. Furthermo re, binders with additional functionalities, such as electrical conductivity and self‐healability, are extensively discussed, with an emphasis on the binder design principle.

Practical evaluation of prelithiation strategies for next‐generation lithium‐ion batteries - Shiming Chen, Zhen Wang, Meng Zhang, Xiaoze Shi, Lu Wang, Weifeng An, Zikun Li, Feng Pan, Luyi Yang (Carbon Energy, 2023)
Abstract With the increasing market demand for high‐performance lithium‐ion batteries with high‐capacity electrode materials, reducing the irreversible capacity loss in the initial cycle and compensating for the active lithium loss during the cycling process are critical challenges. In recent years, various prelithiation strategies have been developed to overcome these issues. Since these approaches are carried out under a wide range of conditions, it is essential to evaluate their suitability for large‐scale commercial applications. In this review, these strategies are categorized based on different battery assembling stages that they are implemented in, including active material synthesis, the slurry mixing process, electrode pretreatment, and battery fabrication. Furthermore, their advantages and disadvantages in commercial production are discussed from the perspective of thermodynamics and kinetics. This review aims to provide guidance for the future development of prelithiation st rategies toward commercialization, which will potentially promote the practical application of next‐generation high‐energy‐density lithium‐ion batteries.

Composition and Structure Design of Poly(vinylidene fluoride)‐Based Solid Polymer Electrolytes for Lithium Batteries - Shengyu Zhou, Shijie Zhong, Yunfa Dong, Zhezhi Liu, Liwei Dong, Botao Yuan, Haodong Xie, Yuanpeng Liu, Liang Qiao, Jiecai Han, Weidong He (Advanced Functional Materials, 2023)
Abstract Solid‐state lithium batteries have become the focus of the next‐generation high‐safety lithium batteries due to their dimensional, thermal, and electrochemical stability. Thus, the progress of solid electrolytes with satisfactory comprehensive performances has become the key to promoting the development of solid batteries. Herein, poly(vinylidene fluoride) (PVDF) solid polymer electrolytes (SPEs) possess excellent flexibility, mechanical property, and high electrochemical and thermal stability, which show huge application potentiality in solid‐state lithium batteries and obtain extensive research. But the PVDF SPEs have been suffering from low ionic conductivity, high crystallinity, and low reactive sites. The development of PVDF‐based composite solid polymer electrolytes (CSPEs) has been confirmed to be a forceful strategy to optimize the performance of electrolytes. In this review, based on different design strategies, the recent progress of PVDF‐based SPEs is introduced in detail, especially in the mechanism of ionic conductivity enhancement and interface regulation by modified fillers. Besides, the applications of PVDF‐based SPEs in Li‐S and Li‐O 2 battery systems are also introduced. Finally, this review presents some insights for promoting the development of high‐performance PVDF‐based SPEs.

High Ionic Conductivity Motivated by Multiple Ion‐Transport Channels in 2D MOF‐Based Lithium Solid State Battery - Huimin Lian, Roya Momen, Yudong Xiao, Bai Song, Xinyu Hu, Fangjun Zhu, Huaxin Liu, Laiqiang Xu, Wentao Deng, Hongshuai Hou, Guoqiang Zou, Xiaobo Ji (Advanced Functional Materials, 2023)
Abstract Metal‐organic frameworks (MOFs) have been proposed as novel fillers for constructing polymer solid electrolytes based composite electrolytes. However, MOFs are generally used as passive fillers, in‐depth revealing the binding mode between MOFs and polyethylene oxide (PEO), the critical role of MOFs in facilitating Li + transport in solid electrolytes is full of challenges. Herein, inspired by density functional theory (DFT) the 2D‐MOF with rich unsaturated metal coordination sites that can bind the O atom in PEO through the metal–oxygen bond, anchor TFSI − to release Li + , resulting in a remarkable Li + transference number of 0.58, is reported according well with the experimental results and molecular dynamics (MD) simulation. Impressively, after the introduction of the 2D‐MOF, the Li + can rapidly hop along the benzene ring center within the 2D‐MOF plane, and the interface between the benzene ring and PEO can also serve as a fast Li + migration pathway, delivering multiple i on‐transport channels, which present a high ion conductivity of 4.6 × 10 −5 S cm −1 (25 °C). The lithium symmetric battery is stable for 1300 h at 60 °C, 0.1 mA cm −2 . The assembled lithium metal solid state battery maintains high capacity of 162.8 mAh g −1 after 500 cycles at 60 °C and 0.5 C. This multiple ion‐transport channels approach brings new ideas for designing advanced solid electrolytes.

Largely Promoted Mechano‐Electrochemical Coupling Properties of Solid Polymer Electrolytes by Introducing Hydrogen Bonds‐Rich Network - Y.W. Ye, Xiaogang Zhu, Nan Meng, Fang Lian (Advanced Functional Materials, 2023)
Abstract Solid polymer electrolytes (SPEs) and their composites are the most promising spices to access the commercial application in all‐solid‐state lithium batteries, where definite requirements for SPEs should be satisfied including moderate mechanical strength, high Li‐ion conductivity, and stable electrode/electrolyte interface. Herein, polyurethane‐based polymer (PNPU) is designed to further construct the hybrid solid polymer electrolyte (named as PNPU‐PVDF‐HFP) with poly(vinylidene fluoride‐ co ‐hexafluoropropylene) (PVDF‐HFP) for high energy density solid‐state lithium metal batteries. The theoretical calculation and characterization demonstrate that PNPU‐PVDF‐HFP SPEs still maintain the multiple hydrogen bonding modes of PNPU, which contributes a significantly improved mechanical properties of the polymer membrane with compact structure. Moreover, it is corroborated that PNPU is involved to form the double Li + transport paths in the hybrid electrolyte, accelerating the migrat ion of lithium ions. Therefore, PNPU‐PVDF‐HFP SPEs are achieved with suitable tensile strength of 5.16 MPa and high elongation of 140.8%, high ambient ionic conductivity of 4.13 × 10 −4 S cm −1 , excellent ductile, and stability on the interface of lithium metal anode. The Li/ LiFePO 4 and Li/Li[Ni 0.8 Co 0.1 Mn 0.1 ]O 2 solid‐state batteries using PNPU‐PVDF‐HFP SPEs present a stable cycling performance at 30 °C. This study provides a feasible strategy to achieve mechano‐electrochemical coupling stable SPEs for solid‐state batteries.

Surface Li2CO3 Mediated Phosphorization Enables Compatible Interfaces of Composite Polymer Electrolyte for Solid‐State Lithium Batteries - Xuerui Yi, Yong Guo, Sijia Chi, Siyuan Pan, Chuannan Geng, Mengyao Li, Zhenshen Li, Wei Lv, Shichao Wu, Quan‐Hong Yang (Advanced Functional Materials, 2023)
Abstract Composite polymer electrolytes (CPEs) are subject to interface incompatibilities due to the space charge layer of ceramic and polymer phases. The intensive dehydrofluorination of poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) incorporating Li 7 La 3 Zr 2 O 12 (LLZO) significantly compromises electro‐chemo‐mechanical properties and compatibilities with electrodes. Herein, this study addresses the challenges by precisely phosphatizing LLZO surfaces through a surface Li 2 CO 3 mediated chemical reaction. The designed neutral chemical environment of LLZO surfaces ensures high air stability and effective suppression of PVDF‐HFP dehydrofluorination. This greatly facilitates the uniform distribution of ceramic and polymer phases, and fast interfacial Li + exchange, establishing high‐throughput ion percolation pathways and distinctly enhancing ionic conductivity and transference number. Moreover, the dramatically reduced formation of dehydrofluorination products and an in situ formed interphase layer between phosphatized surface and a Li metal anode stabilize the Li/CPE and cathode/CPE interfaces, which provide a symmetric Li/Li cell and solid‐state Li/LiFePO 4 and Li/LiNi 0.8 Co 0.1 Mn 0.1 O 2 cells an exceptional cycling performance at room temperature. This study emphasizes the vital importance of achieving electro‐chemo‐mechanical compatibilities for CPEs and provides a new waste to wealth route.

The Influences of DMF Content in Composite Polymer Electrolytes on Li+‐Conductivity and Interfacial Stability with Li‐Metal - Jianxun Zhu, Shuang He, Huayang Tian, Yiming Hu, Chen Xin, Xiaoxin Xie, Lipeng Zhang, Lipeng Zhang, Jian Gao, Shu‐Meng Hao, Weidong Zhou, Liqun Zhang, Liqun Zhang (Advanced Functional Materials, 2023)
Abstract Trace N, N‐dimethylformamide(DMF) containing composite polymer electrolytes (CPEs) has attracted much attention owing to the dramatically increased Li + ‐conductivity. But the amount of DMF is critical and needs to be clarified for the interfacial stability, since DMF is easily reduced by Li‐metal. Herein, the influences of DMF in poly(ethylene oxide) (PEO) and poly(vinylidene fluoride) (PVDF) based CPEs are studied on the Li + ‐conductivity and interfacial stability. In PEO‐based CPEs, owing to a stronger interaction of lithium bis(trifluoromethanesulfon)imide (LiTFSI) with PEO than DMF, DMF can not be confined and be easily evaporated off. Only ≈0.25wt.% DMF is absorbed on ceramic electrolyte fillers, giving two times increased Li + ‐conductivity compared with the DMF‐free counterparts and generating stable interface with Li‐metal; but over much DMF (≥2.2 wt.%) leads to serious interfacial reactions with Li‐metal. While in PVDF‐based CPEs, ≈8wt.% DMF is confined by LiTFSI ow ing to a stronger interaction of LiTFSI with DMF than with PVDF. Short‐term stable interface with Li‐metal can be obtained, but longer‐term cycling or higher current density leads to the gradually aggravated reactions with Li‐metal. Thanks to the high‐voltage stability of PVDF based CPEs, better cycling performance is obtained when they are used as catholytes to match high‐voltage cathodes.

A Safe Separator with Heat‐Dispersing Channels for High‐Rate Lithium‐Ion Batteries - Botao Yuan, Yuhan Feng, Xinghan Qiu, Yuhui He, Liwei Dong, Shijie Zhong, Jipeng Liu, Yifang Liang, Yuanpeng Liu, Haodong Xie, Zhezhi Liu, Jiecai Han, Weidong He (Advanced Functional Materials, 2023)
Abstract Separators are becoming increasingly important in both academic research and industrial production as a means of enhancing the performance of lithium‐ion batteries (LIBs), particularly at a high rate. However, fast charge–discharge processes will produce local heat accumulation, which accelerates the local reaction rate of Li + to form lithium dendrites. Commercial polyolefin separators fail to tackle the above issue due to inferior thermal stability. Herein, a core–shell structure is proposed to reinforce the polyvinylidene fluoride‐hexafluoropropylene (PVDF‐HFP) matrix through encircling carbon nanotube (CNT) by adherent polydopamine (PDA). The core–shell 3D structure with PDA avoids the short circuits caused by the electrically conductive CNT, and meantime, the CNT serves as an effective radiator for dispersing local heat sources verified through finite element analysis. The composite separator allows LIBs to achieve high Li + conductivity (0.49 × 10 −3 S cm −1 ) and Li + t ransfer number (0.74), resulting in a high capacity retention of 87.35% after 800 cycles at 5C. In particular, the safety is confirmed that the composite separator avoids violent growth of lithium dendrites caused by local heat accumulation through phase‐field simulations. This work suggests a promising approach for the fabrication of core–shell nanotube composite separators for high‐rate and safe LIBs.

A Coacervate-Based Mixed-Conducting Binder for High-Power, High-Energy Batteries - Gordon Pace, My Linh Le, Raphaële J. Clément, Rachel A. Segalman (ACS Energy Letters, 2023)
Polymer binders add crucial structural integrity to lithium ion battery composite cathodes, but industry standard binders, such as polyvinylidene fluoride (PVDF), are insulating to ions and electrons, detrimentally adding resistance to the overall system. In this work, we use electrostatics to stabilize a blend of a charged conjugated polymer with an oppositely charged polyelectrolyte, providing a processable, stable binder with high ionic and electronic conduction. Using LiFePO 4 cathodes as a model system, we show significant improvement in rate capability and stability, with the conducting binder enabling a 39% utilization at 6C compared to 1.6% when PVDF is the binder. Additionally, the conducting binder affords a 63% capacity retention over 400 C/2 cycles, compared to only a 6% retention over 400 cycles when PVDF is the binder. These results show that electrostatically stabilized complexation is a promising strategy to integrate both electronic and ionic conductivity into a binder , while simultaneously maintaining stability and processability.

Achieving high-energy and high-safety lithium metal batteries with high-voltage-stable solid electrolytes - Zi-You Wang, Chen‐Zi Zhao, Shuo Sun, Yukun Liu, Zixuan Wang, Shuai Li, Rui Zhang, Hong Yuan, Jia‐Qi Huang (Matter, 2023)

High Dielectric Poly(vinylidene fluoride)‐Based Polymer Enables Uniform Lithium‐Ion Transport in Solid‐State Ionogel Electrolytes - Jun‐Feng Liu, Zhanyu Wu, Florian J. Stadler, Yanfei Huang (Angewandte Chemie International Edition, 2023)
Abstract Ionic liquids (ILs)‐incorporated solid‐state polymer electrolytes (iono‐SPEs) have high ionic conductivities but show non‐uniform Li + transport in different phases. This work greatly promotes Li + transport in polymer phases by employing a poly (vinylidene fluoride‐trifluoroethylene‐chlorotrifluoroethylene) [P(VDF‐TrFE‐CTFE), PTC] as the framework of ILs to prepare iono‐SPEs. Unlike PVDF, PTC with suitable polarity shows weaker adsorption energy on IL cations, reducing their possibility of occupying Li + ‐hopping sites. The significantly higher dielectric constant of PTC than PVDF facilitates the dissociation of Li‐anions clusters. These two factors motivate Li + transport along PTC chains, narrowing the difference in Li + transport among varied phases. The LiFePO 4 /PTC iono‐SPE/Li cells cycle steadily with capacity retention of 91.5 % after 1000 cycles at 1 C and 25 °C. This work paves a new way to induce uniform Li + flux in iono‐SPEs through polarity and dielectric design of polymer matrix.

Ultrafast high-temperature sintering of high-entropy oxides with refined microstructure and superior lithium-ion storage performance - Yuhang Bai, Jingrui Li, Haiming Lu, Jia Liu, Cuiying Ma, Bin Wang, Xing Zhao, Jun Deng (Journal of Advanced Ceramics, 2023)
High-entropy oxides (HEOs) have received significant attention because of their tunable mechanical properties and wide-range of functional applications. However, the conventional method used for sintering HEOs requires a prolonged processing time, which results in excessive grain growth, thereby compromising their performance. Here, an ultrafast high-temperature sintering (UHS) strategy was adopted and the rock-salt composite (Mg0.2Co0.2Ni0.2Cu0.2Zn0.2)O was selected as a model material. The experimental parameters were tuned to illustrate the influence of the applied current and soaking time on the densification process and resulting grain size. Additionally, the electrochemical performance of UHS-synthesized microparticles as the anode material in lithium-ion batteries was investigated. The results show that the ultrafast heating rate results in fine grains with a diameter of ~6–8 μm and a density of 95%, which are, respectively, much smaller and similar to those obtained using the conventional sintering method (25 μm and 96%). Moreover, the high surface area and reactivity of the microparticles, as well as their sluggish diffusion effect and structural stability, contribute to an outstanding performance with high capacity (336 mAh/g at 1 A/g) and ultralong cyclability (1000 cycles). This novel technique offers valuable insights into the densification process of HEOs and other materials and can thus broaden their application range.

Advances in inorganic, polymer and composite electrolytes: Mechanisms of Lithium-ion transport and pathways to enhanced performance - Kato Daems, Poonam Yadav, Kamil Burak Dermenci, Joeri Van Mierlo, Maitane Berecibar (Renewable and Sustainable Energy Reviews, 2023)
The growing demand for enhanced batteries with higher energy density and safety is pushing lithium-ion battery technology towards solid-state batteries. Replacing the liquid with a solid electrolyte significantly improves safety by removing the possibility of leaking flammable organic solvents. Solid electrolytes also enable the use of lithium metal as anode material to obtain battery cells with higher energy density. This review summarizes the classification of all three state-of-the-art solid electrolyte types (inorganic, polymer and composite solid electrolytes) and their governing lithium ion transport mechanisms. Nevertheless, to make solid-state batteries applicable, improvements in ionic conductivity of the solid electrolyte, low electrode-electrolyte interfacial resistance and high compatibility of the solid electrolyte with the electrodes are required. This review paper discusses improvement strategies for solid electrolytes to achieve high ionic conductivity, good flexibility , and high electrode compatibility. Enhanced ionic conductivity can be obtained by suppressing the polymer phase's crystallization (e.g., copolymerization, inorganic fillers, adjusting polymer matrix) and optimizing the physicochemical parameters and the surface of the inorganic phase. Interfacial stability can be improved by using multilayered electrolytes or applying coatings and passivation layers on electrolyte or electrode particles.

Uniform Lithium Plating for Dendrite-Free Lithium Metal Batteries: Role of Dipolar Channels in Poly(vinylidene fluoride) and PbZrxTi1–xO3 Interface - Ben-hao Kang, Shuang-Feng Li, Jinlong Yang, Zhong‐Ming Li, Yanfei Huang (ACS Nano, 2023)
Conventional polymer/ceramic composite solid-state electrolytes (CPEs) have limitations in inhibiting lithium dendrite growth and fail to meet the contradictory requirements of anodes and cathodes. Herein, an asymmetrical poly(vinylidene fluoride) (PVDF)–PbZr x Ti 1– x O 3 (PZT) CPE was prepared. The CPE incorporates high dielectric PZT nanoparticles, which enrich a dense thin layer on the anode side, making their dipole ends strongly electronegative. This attracts lithium ions (Li + ) at the PVDF–PZT interface to transport through dipolar channels and promotes the dissociation of lithium salts into free Li + . Consequently, the CPE enables homogeneous lithium plating and suppresses dendrite growth. Meanwhile, the PVDF-enriched region at the cathode side ensures intermediate contact with positive active materials. Therefore, Li/PVDF-PZT CPE/Li symmetrical cells exhibit a stable cycling performance exceeding 1900 h at 0.1 mA cm –2 at 25 °C, outperforming Li/PVDF solid-state electrolyte/ Li cells that fail after 120 h. The LiNi 0.8 Co 0.1 Mo 0.1 O 2 /PVDF–PZT CPE/Li cells show low interfacial impedances and maintain stable cycling performance for 500 cycles with a capacity retention of 86.2% at 0.5 C and 25 °C. This study introduces a strategy utilizing dielectric ceramics to construct dipolar channels, providing a uniform Li + transport mechanism and inhibiting dendrite growth.

Ultrahigh loading dry-process for solvent-free lithium-ion battery electrode fabrication - Minje Ryu, Young‐Kuk Hong, Sang‐Young Lee, Jong Hyeok Park (Nature Communications, 2023)
Abstract The current lithium-ion battery (LIB) electrode fabrication process relies heavily on the wet coating process, which uses the environmentally harmful and toxic N-methyl-2-pyrrolidone (NMP) solvent. In addition to being unsustainable, the use of this expensive organic solvent substantially increases the cost of battery production, as it needs to be dried and recycled throughout the manufacturing process. Herein, we report an industrially viable and sustainable dry press-coating process that uses the combination of multiwalled carbon nanotubes (MWNTs) and polyvinylidene fluoride (PVDF) as a dry powder composite and etched Al foil as a current collector. Notably, the mechanical strength and performance of the fabricated LiNi 0.7 Co 0.1 Mn 0.2 O 2 (NCM712) dry press-coated electrodes (DPCEs) far exceed those of conventional slurry-coated electrodes (SCEs) and give rise to high loading (100 mg cm −2 , 17.6 mAh cm −2 ) with impressive specific energy and volumetric energy density of 360 Wh kg −1 and 701 Wh L −1 , respectively.

Dynamic gel as artificial interphase layer for ultrahigh-rate and large-capacity lithium metal anode - Chao Chen, Jiaming Zhang, Benrui Hu, Qianwen Liang, Xunhui Xiong (Nature Communications, 2023)
Abstract Constructing a stable artificial solid-electrolyte interphase has become one of the most effective strategies to overcome the poor reversibility of lithium metal anode, yet the protection role is still insufficient at elevated current densities over 10 mA cm −2 and large areal capacities over 10 mAh cm −2 . Herein, we propose a dynamic gel with reversible imine groups, which is prepared via a cross linking reaction between flexible dibenzaldehyde-terminated telechelic poly(ethylene glycol) and rigid chitosan, to fabricate a protective layer for Li metal anode. The as-prepared artificial film shows combined merits of high Young’s modulus, strong ductility and high ionic conductivity. When the artificial film is fabricated on a lithium metal anode, the thin protective layer shows a dense and uniform surface owing to the interactions between the abundant polar groups and lithium metal. Besides, the polar groups in the artificial film can homogenize the distribution of Li + at the electrode/electrolyte interface. As a result, cycle stability over 3200 h under an areal capacity of 10 mAh cm −2 and a current density of 10 mA cm −2 has been obtained for the protected lithium metal anodes. Moreover, cycling stability and rate capability has been also improved in the full cells.

Tailoring chemical composition of solid electrolyte interphase by selective dissolution for long-life micron-sized silicon anode - Yi-Fan Tian, Shuang‐Jie Tan, Chunpeng Yang, Yuming Zhao, Di‐Xin Xu, Zhuo‐Ya Lu, Ge Li, Jinyi Li, Xusheng Zhang, Chaohui Zhang, Jilin Tang, Yao Zhao, Fuyi Wang, Rui Wen, Quan Xu, Yu‐Guo Guo (Nature Communications, 2023)
Abstract Micron-sized Si anode promises a much higher theoretical capacity than the traditional graphite anode and more attractive application prospect compared to its nanoscale counterpart. However, its severe volume expansion during lithiation requires solid electrolyte interphase (SEI) with reinforced mechanical stability. Here, we propose a solvent-induced selective dissolution strategy to in situ regulate the mechanical properties of SEI. By introducing a high-donor-number solvent, gamma-butyrolactone, into conventional electrolytes, low-modulus components of the SEI, such as Li alkyl carbonates, can be selectively dissolved upon cycling, leaving a robust SEI mainly consisting of lithium fluoride and polycarbonates. With this strategy, raw micron-sized Si anode retains 87.5% capacity after 100 cycles at 0.5 C (1500 mA g −1 , 25°C), which can be improved to >300 cycles with carbon-coated micron-sized Si anode. Furthermore, the Si||LiNi 0.8 Co 0.1 Mn 0.1 O 2 battery using the raw micron-sized Si anode with the selectively dissolved SEI retains 83.7% capacity after 150 cycles at 0.5 C (90 mA g −1 ). The selective dissolution effect for tailoring the SEI, as well as the corresponding cycling life of the Si anodes, is positively related to the donor number of the solvents, which highlights designing high-donor-number electrolytes as a guideline to tailor the SEI for stabilizing volume-changing alloying-type anodes in high-energy rechargeable batteries.

A corrosion inhibiting layer to tackle the irreversible lithium loss in lithium metal batteries - Chengbin Jin, Yiyu Huang, L. P. Li, Guoying Wei, Hongyan Li, Qiyao Shang, Zhijin Ju, Gongxun Lu, Jiale Zheng, Ouwei Sheng, Xinyong Tao (Nature Communications, 2023)
Abstract Reactive negative electrodes like lithium (Li) suffer serious chemical and electrochemical corrosion by electrolytes during battery storage and operation, resulting in rapidly deteriorated cyclability and short lifespans of batteries. Li corrosion supposedly relates to the features of solid-electrolyte-interphase (SEI). Herein, we quantitatively monitor the Li corrosion and SEI progression (e.g., dissolution, reformation) in typical electrolytes through devised electrochemical tools and cryo-electron microscopy. The continuous Li corrosion is validated to be positively correlated with SEI dissolution. More importantly, an anti-corrosion and interface-stabilizing artificial passivation layer comprising low-solubility polymer and metal fluoride is designed. Prolonged operations of Li symmetric cells and Li | |LiFePO 4 cells with reduced Li corrosion by ~74% are achieved (0.66 versus 2.5 μAh h −1 ). The success can further be extended to ampere-hour-scale pouch cells. This work u ncovers the SEI dissolution and its correlation with Li corrosion, enabling the durable operation of Li metal batteries by reducing the Li loss.

Naked metallic skin for homo-epitaxial deposition in lithium metal batteries - Minsung Baek, Jin Young Kim, Kwanghoon Jeong, Seonmo Yang, Heejin Kim, Jimin Lee, Minkwan Kim, Ki Jae Kim, Jang Wook Choi (Nature Communications, 2023)
Abstract Regulating the morphology of lithium plating is the key to extending the cycle life of lithium metal batteries. Fatal dendritic growth is closely related to out-of-plane nucleation on the lithium metal surface. Herein, we report a nearly perfect lattice match between the lithium metal foil and lithium deposits by removing the native oxide layer using simple bromine-based acid-base chemistry. The naked lithium surface induces homo-epitaxial lithium plating with columnar morphologies and lower overpotentials. Using the naked lithium foil, the lithium-lithium symmetric cell maintains stable cycling at 10 mA cm −2 for more than 10,000 cycles, and the full-cell paired with LiFePO 4 with high areal capacity of 3.3 mAh cm −2 and practical N/P ratio of 2.5 exhibits 86% capacity retention after 300 cycles. This study elucidates the usefulness of controlling the initial surface state to facilitate homo-epitaxial lithium plating for sustainable cycling of lithium metal batteries.

Intercalation-type catalyst for non-aqueous room temperature sodium-sulfur batteries - Jiarui He, Amruth Bhargav, Laisuo Su, Harry Charalambous, Arumugam Manthiram (Nature Communications, 2023)
Abstract Ambient-temperature sodium-sulfur (Na-S) batteries are potential attractive alternatives to lithium-ion batteries owing to their high theoretical specific energy of 1,274 Wh kg −1 based on the mass of Na 2 S and abundant sulfur resources. However, their practical viability is impeded by sodium polysulfide shuttling. Here, we report an intercalation-conversion hybrid positive electrode material by coupling the intercalation-type catalyst, MoTe 2 , with the conversion-type active material, sulfur. In addition, MoTe 2 nanosheets vertically grown on graphene flakes offer abundant active catalytic sites, further boosting the catalytic activity for sulfur redox. When used as a composite positive electrode and assembled in a coin cell with excess Na, a discharge capacity of 1,081 mA h g s −1 based on the mass of S with a capacity fade rate of 0.05% per cycle over 350 cycles at 0.1 C rate in a voltage range of 0.8 to 2.8 V is realized under a high sulfur loading of 3.5 mg cm −2 and a lean electrolyte condition with an electrolyte-to-sulfur ratio of 7 μL mg −1 . A fundamental understanding of the electrocatalysis of MoTe 2 is further revealed by in-situ synchrotron-based operando X-ray diffraction and ex-situ time-of-flight secondary ion mass spectrometry.

Precise solid-phase synthesis of CoFe@FeOx nanoparticles for efficient polysulfide regulation in lithium/sodium-sulfur batteries - Yanping Chen, Yu Yao, Wantong Zhao, Lifeng Wang, Haitao Li, Jiangwei Zhang, Baojun Wang, Yi Jia, Riguang Zhang, Yan Yu, Jian Liu (Nature Communications, 2023)
Abstract Complex metal nanoparticles distributed uniformly on supports demonstrate distinctive physicochemical properties and thus attract a wide attention for applications. The commonly used wet chemistry methods display limitations to achieve the nanoparticle structure design and uniform dispersion simultaneously. Solid-phase synthesis serves as an interesting strategy which can achieve the fabrication of complex metal nanoparticles on supports. Herein, the solid-phase synthesis strategy is developed to precisely synthesize uniformly distributed CoFe@FeO x core@shell nanoparticles. Fe atoms are preferentially exsolved from CoFe alloy bulk to the surface and then be carburized into a Fe x C shell under thermal syngas atmosphere, subsequently the formed Fe x C shell is passivated by air, obtaining CoFe@FeO x with a CoFe alloy core and a FeO x shell. This strategy is universal for the synthesis of MFe@FeO x (M = Co, Ni, Mn). The CoFe@FeO x exhibits bifunctional effect on regulating poly sulfides as the separator coating layer for Li-S and Na-S batteries. This method could be developed into solid-phase synthetic systems to construct well distributed complex metal nanoparticles.

Atomic-scale origin of the low grain-boundary resistance in perovskite solid electrolyte Li0.375Sr0.4375Ta0.75Zr0.25O3 - Tom Lee, Ji Qi, Chaitanya Gadre, Huaixun Huyan, Shu‐Ting Ko, Yunxing Zuo, Chaojie Du, Jie Li, Toshihiro Aoki, Ruqian Wu, Jian Luo, Shyue Ping Ong, Xiaoqing Pan (Nature Communications, 2023)
Abstract Oxide solid electrolytes (OSEs) have the potential to achieve improved safety and energy density for lithium-ion batteries, but their high grain-boundary (GB) resistance generally is a bottleneck. In the well-studied perovskite oxide solid electrolyte, Li 3 x La 2/3x TiO 3 (LLTO), the ionic conductivity of grain boundaries is about three orders of magnitude lower than that of the bulk. In contrast, the related Li 0.375 Sr 0.4375 Ta 0.75 Zr 0.25 O 3 (LSTZ0.75) perovskite exhibits low grain boundary resistance for reasons yet unknown. Here, we use aberration-corrected scanning transmission electron microscopy and spectroscopy, along with an active learning moment tensor potential, to reveal the atomic scale structure and composition of LSTZ0.75 grain boundaries. Vibrational electron energy loss spectroscopy is applied for the first time to reveal atomically resolved vibrations at grain boundaries of LSTZ0.75 and to characterize the otherwise unmeasurable Li distribution therein. We find that Li depletion, which is a major reason for the low grain boundary ionic conductivity of LLTO, is absent for the grain boundaries of LSTZ0.75. Instead, the low grain boundary resistivity of LSTZ0.75 is attributed to the formation of a nanoscale defective cubic perovskite interfacial structure that contained abundant vacancies. Our study provides new insights into the atomic scale mechanisms of low grain boundary resistivity.

A non-Newtonian fluid quasi-solid electrolyte designed for long life and high safety Li-O2 batteries - Guangli Zheng, Tong Yan, Yifeng Hong, Xiaona Zhang, Jian‐Ying Wu, Zhenxing Liang, Zhiming Cui, Li Du, Huiyu Song (Nature Communications, 2023)
Abstract The Li dendrite growth and the liquid electrolyte volatilization under semi-open architecture are intrinsic issues for Li-O 2 battery. In this work, we propose a non-Newtonian fluid quasi-solid electrolyte (NNFQSE) SiO 2 -SO 3 Li/PVDF-HFP, which has both shear-thinning and shear-thickening properties. The component interactions among the sulfonated silica nanoparticles, liquid electrolyte, and polymer network are beneficial for decent Li + conductivity and high liquid electrolyte retention without volatilization. Furthermore, NNFQSE exhibits shear-thinning property to eliminate the stress of dendrite growth during repeated cycling. Meanwhile, when the force suddenly increases, such as a high current rate, the NNFQSE may dynamically turn shear-thickening to respond and mechanically stiffen to inhibit the lithium dendrite penetration. By coupling with the NNFQSE, the lithium symmetrical battery can run over 2000 h under 1 mA cm −2 at room temperature, and the quasi-solid Li-O 2 battery actualizes long life above 5000 h at 100 mA g −1 .

Weakly coordinated Li ion in single-ion-conductor-based composite enabling low electrolyte content Li-metal batteries - Hyeokjin Kwon, Hyun-Ji Choi, Jung-Kyu Jang, Jin Hong Lee, Jinkwan Jung, Wonjun Lee, Youngil Roh, Jaewon Baek, Dong Jae Shin, Ju‐Hyuk Lee, Nam‐Soon Choi, Ying Shirley Meng, Hee‐Tak Kim (Nature Communications, 2023)
Abstract The pulverization of lithium metal electrodes during cycling recently has been suppressed through various techniques, but the issue of irreversible consumption of the electrolyte remains a critical challenge, hindering the progress of energy-dense lithium metal batteries. Here, we design a single-ion-conductor-based composite layer on the lithium metal electrode, which significantly reduces the liquid electrolyte loss via adjusting the solvation environment of moving Li + in the layer. A Li||Ni 0.5 Mn 0.3 Co 0.2 O 2 pouch cell with a thin lithium metal (N/P of 2.15), high loading cathode (21.5 mg cm −2 ), and carbonate electrolyte achieves 400 cycles at the electrolyte to capacity ratio of 2.15 g Ah −1 (2.44 g Ah −1 including mass of composite layer) or 100 cycles at 1.28 g Ah −1 (1.57 g Ah −1 including mass of composite layer) under a stack pressure of 280 kPa (0.2 C charge with a constant voltage charge at 4.3 V to 0.05 C and 1.0 C discharge within a voltage window of 4.3 V to 3.0 V). The rational design of the single-ion-conductor-based composite layer demonstrated in this work provides a way forward for constructing energy-dense rechargeable lithium metal batteries with minimal electrolyte content.

Ion–Dipole-Interaction-Induced Encapsulation of Free Residual Solvent for Long-Cycle Solid-State Lithium Metal Batteries - Menglu Li, Hanwen An, Yajie Song, Qingsong Liu, Jian Wang, Jian Wang, Hua Huo, Shuaifeng Lou, Jiajun Wang, Jiajun Wang (Journal of the American Chemical Society, 2023)
Owing to high ionic conductivity and mechanical strength, poly(vinylidene fluoride) (PVDF) electrolytes have attracted increasing attention for solid-state lithium batteries, but highly reactive residual solvents severely plague cycling stability. Herein, we report a free-solvent-capturing strategy triggered by reinforced ion–dipole interactions between Li + and residual solvent molecules. Lithium difluoro(oxalato)borate (LiDFOB) salt additive with electron-withdrawing capability serves as a redistributor of the Li + electropositive state, which offers more binding sites for residual solvents. Benefiting from the modified coordination environment, the kinetically stable anion-derived interphases are preferentially formed, effectively mitigating the interfacial side reactions between the electrodes and electrolytes. As a result, the assembled solid-state battery shows a lifetime of over 2000 cycles with an average Coulombic efficiency of 99.9% and capacity retention of 80%. Our discover y sheds fresh light on the targeted regulation of the reactive residual solvent to extend the cycle life of solid-state batteries.

Suppressing Local Dendrite Hotspots via Current Density Redistribution Using a Superlithiophilic Membrane for Stable Lithium Metal Anode - Yifan Hu, Zichuang Li, Zongpeng Wang, Xunlu Wang, Wei Chen, Jiacheng Wang, Wenwu Zhong, Ruguang Ma (Advanced Science, 2023)
Abstract Li metal anode is considered as one of the most desirable candidates for next‐generation battery due to its lowest electrochemical potential and high theoretical capacity. However, undesirable dendrite growth severely exacerbates the interfacial stability, thus damaging battery performance and bringing safety concerns. Here, an efficient strategy is proposed to stabilize Li metal anode by digesting dendrites sprout using a 3D flexible superlithiophilic membrane consisting of poly(vinylidene fluoride) (PVDF) and ZnCl 2 composite nanofibers (PZEM) as a protective layer. Both the experimental studies and theoretical calculations show the origin of superlithiophilicity ascribed to a strong interaction between ZnCl 2 and PVDF to form the ZnF bonds. The multifield physics calculation implies effective removal of local dendrite hotspots by PZEM via a more homogeneous Li + flux. The PZEM‐covered Li anode (PZEM@Li) exhibits superior Li deposition/stripping performance in a symmetric c ell over 1100 cycles at a high current density of 5 mA cm −2 . When paired with LiFePO 4 (LFP), PZEM@Li|LFP full cell remains stable over 1000 cycles at 2 C with a degradation rate of 0.0083% per cycle. This work offers a new route for efficient protection of Li metal anode for practical applications.

Preparation of Tough, Binder‐Free, and Self‐Supporting LiFePO4 Cathode by Using Mono‐Dispersed Ultra‐Long Single‐Walled Carbon Nanotubes for High‐Rate Performance Li‐Ion Battery - Mingyi Guo, Zengqiang Cao, Yukang Liu, Yuxiang Ni, Xianchun Chen, Mauricio Terrones, Yanqing Wang (Advanced Science, 2023)
Abstract Low‐contents/absence of non‐electrochemical activity binders, conductive additives, and current collectors are a concern for improving lithium‐ion batteries' fast charging/discharging performance and developing free‐standing electrodes in the aspects of flexible/wearable electronic devices. Herein, a simple yet powerful fabricating method for the massive production of mono‐dispersed ultra‐long single‐walled carbon nanotubes (SWCNTs) in N ‐methyl‐2‐pyrrolidone solution, benefiting from the electrostatic dipole interaction and steric hindrance of dispersant molecules, is reported. These SWCNTs form a highly efficient conductive network to firmly fix LiFePO 4 (LFP) particles in the electrode at low contents of 0.5 wt% as conductive additives. The binder‐free LFP/SWCNT cathode delivers a superior rate capacity of 161.5 mAh g −1 at 0.5 C and 130.2 mAh g −1 at 5 C, with a high‐rate capacity retention of 87.4% after 200 cycles at 2 C. The self‐supporting LFP/SWCNT cathode shows excel lent mechanical properties, which can withstand at least 7.2 MPa stress and 5% strain, allowing the fabrication of high mass loading electrodes with thicknesses up to 39.1 mg cm −2 . Such self‐supporting electrodes display conductivities up to 1197 S m −1 and low charge‐transfer resistance of 40.53 Ω, allowing fast charge delivery and enabling near‐theoretical specific capacities.

In Situ Polymerization on a 3D Ceramic Framework of Composite Solid Electrolytes for Room‐Temperature Solid‐State Batteries - An‐Giang Nguyen, Rakesh Verma, Geon‐Chang Song, Jaekook Kim, Chan‐Jin Park (Advanced Science, 2023)
Abstract Solid‐state batteries (SSBs) are ideal candidates for next‐generation high‐energy‐density batteries in the Battery of Things era. Unfortunately, SSB application is limited by their poor ionic conductivity and electrode‐electrolyte interfacial compatibility. Herein, in situ composite solid electrolytes (CSEs) are fabricated by infusing vinyl ethylene carbonate monomer into a 3D ceramic framework to address these challenges. The unique and integrated structure of CSEs generates inorganic, polymer, and continuous inorganic–polymer interphase pathways that accelerate ion transportation, as revealed by solid‐state nuclear magnetic resonance (SSNMR) analysis. In addition, the mechanism and activation energy of Li + transportation are studied and visualized by performing density functional theory calculations. Furthermore, the monomer solution can penetrate and polymerize in situ to form an excellent ionic conductor network inside the cathode structure. This concept is successfully a pplied to both solid‐state lithium and sodium batteries. The Li|CSE|LiNi 0.8 Co 0.1 Mn 0.1 O 2 cell fabricated herein delivers a specific discharge capacity of 118.8 mAh g −1 after 230 cycles at 0.5 C and 30 °C. Meanwhile, the Na|CSE|Na 3 Mg 0.05 V 1.95 (PO 4 ) 3 @C cell fabricated herein maintains its cycling stability over 3000 cycles at 2 C and 30 °C with zero‐fading. The proposed integrated strategy provides a new perspective for designing fast ionic conductor electrolytes to boost high‐energy solid‐state batteries.

Exceptional n-type thermoelectric ionogels enabled by metal coordination and ion-selective association - Wei Zhao, Yiwei Zheng, Meng Jiang, Tingting Sun, Aibin Huang, Lianjun Wang, Wan Jiang, Qihao Zhang (Science Advances, 2023)
Ionic liquid-based ionogels emerge as promising candidates for efficient ionic thermoelectric conversion due to their quasi-solid state, giant thermopower, high flexibility, and good stability. P-type ionogels have shown impressive performance; however, the development of n-type ionogels lags behind. Here, an n-type ionogel consisting of polyethylene oxide (PEO), lithium salt, and ionic liquid is developed. Strong coordination of lithium ion with ether oxygen and the anion-rich clusters generated by ion-preferential association promote rapid transport of the anions and boost Eastman entropy change, resulting in a huge negative ionic Seebeck coefficient (-15 millivolts per kelvin) and a high electrical conductivity (1.86 millisiemens per centimeter) at 50% relative humidity. Moreover, dynamic and reversible interactions among the ternary mixtures endow the ionogel with fast autonomous self-healing capability and green recyclability. All PEO-based ionic thermoelectric modules are fabrica ted, which exhibits outstanding thermal responses (-80 millivolts per kelvin for three p-n pairs), demonstrating great potential for low-grade energy harvesting and ultrasensitive thermal sensing.

Boosting Thermal and Mechanical Properties: Achieving High‐Safety Separator Chemically Bonded with Nano TiN Particles for High Performance Lithium‐Ion Batteries - Qian Zhao, Xiulong Wu, Shenghu Li, Qiaotian Zheng, Shuai Jiang, Ye Xu, Bin He, Ling Ma, Yangtong Luo, Yujue Wang, Wanglai Cen, Yan Meng, Dan Xiao (Small, 2023)
Abstract Currently, the commercial separator (Celgard2500) of lithium‐ion batteries (LIBs) suffers from poor electrolyte affinity, mechanical property and thermal stability, which seriously affect the electrochemical performances and safety of LIBs. Here, the composite separators named PVDF‐HFP/TiN for high‐safety LIBs are synthesized. The integration of PVDF‐HFP and TiN forms porous structure with a uniform and rich organic framework. TiN significantly improves the adsorption between PVDF‐HFP and electrolyte, causing a higher electrolyte absorption rate (192%). Meanwhile, XPS results further demonstrate the tight link between PVDF‐HFP and TiN due to the existence of TiF bond in PVDF‐HFP/TiN, resulting in a strong impediment for the puncture of lithium dendrites as a result of the improved mechanical strengths. And PVDF‐HFP/TiN can effectively suppress the growth of lithium dendrites by means of uniform lithium flux. In addition, the excellent heat resistance of TiN improves the therm al stability of PVDF‐HFP/TiN. As a result, the LiFePO 4 ||Li cells assembled PVDF‐HFP/TiN‐12 exhibit excellent specific capacity, rate performance, and capacity retention rate. Even the high specific capacity of 153 mAh g −1 can be obtained at the high temperature of 80 °C. Meaningfully, a reliable modification strategy for the preparation of separators with high safety and electrochemical performance in LIBs is provided.

Recent progress and challenges in silicon-based anode materials for lithium-ion batteries - Gazi Farhan Ishraque Toki, M. Khalid Hossain, Waheed Ur Rehman, Rana Zafar Abbas Manj, Li Wang, Jianping Yang (Industrial Chemistry and Materials, 2023)
This review highlights the importance of silicon-based anodes in lithium-ion batteries, emphasizing their improved performance through modifications involving binders, coatings, composites, and electrolytes.

Design of functional binders for high-specific-energy lithium-ion batteries: from molecular structure to electrode properties - Qin Tian, Haoyi Yang, Quan Li, Xiqian Yu, Hong Li (Industrial Chemistry and Materials, 2023)
This review systematically summarizes the research progress of functional binders in lithium-ion batteries and elucidates the main functions of advanced binders to deal with the challenges of high-specific-energy electrodes.

Plasmonic semiconductors: materials, tunability and applications - Yüjie Guo, Zhenyu Xu, Alberto G. Curto, Y. J. Zeng, Dries Van Thourhout (Progress in Materials Science, 2023)

Artificial visual perception neural system using a solution-processable MoS2-based in-memory light sensor - Dayanand Kumar, Lana Joharji, Hanrui Li, Ayman Rezk, Ammar Nayfeh, Nazek El‐Atab (Light Science & Applications, 2023)
Abstract Optoelectronic devices are advantageous in in-memory light sensing for visual information processing, recognition, and storage in an energy-efficient manner. Recently, in-memory light sensors have been proposed to improve the energy, area, and time efficiencies of neuromorphic computing systems. This study is primarily focused on the development of a single sensing-storage-processing node based on a two-terminal solution-processable MoS 2 metal–oxide–semiconductor (MOS) charge-trapping memory structure—the basic structure for charge-coupled devices (CCD)—and showing its suitability for in-memory light sensing and artificial visual perception. The memory window of the device increased from 2.8 V to more than 6 V when the device was irradiated with optical lights of different wavelengths during the program operation. Furthermore, the charge retention capability of the device at a high temperature (100 °C) was enhanced from 36 to 64% when exposed to a light wavelength of 400 nm. The larger shift in the threshold voltage with an increasing operating voltage confirmed that more charges were trapped at the Al 2 O 3 /MoS 2 interface and in the MoS 2 layer. A small convolutional neural network was proposed to measure the optical sensing and electrical programming abilities of the device. The array simulation received optical images transmitted using a blue light wavelength and performed inference computation to process and recognize the images with 91% accuracy. This study is a significant step toward the development of optoelectronic MOS memory devices for neuromorphic visual perception, adaptive parallel processing networks for in-memory light sensing, and smart CCD cameras with artificial visual perception capabilities.

Microsphere femtosecond laser sub-50 nm structuring in far field via non-linear absorption - Zhenyuan Lin, Kuan Liu, Tun Cao, Minghui Hong (Opto-Electronic Advances, 2023)
Creation of arbitrary features with high resolution is critically important in the fabrication of nano-optoelectronic devices. Here, sub-50 nm surface structuring is achieved directly on Sb2S3 thin films via microsphere femtosecond laser irradiation in far field. By varying laser fluence and scanning speed, nano-feature sizes can be flexibly tuned. Such small patterns are attributed to the co-effect of microsphere focusing, two-photons absorption, top threshold effect, and high-repetition-rate femtosecond laser-induced incubation effect. The minimum feature size can be reduced down to ~30 nm (λ/26) by manipulating film thickness. The fitting analysis between the ablation width and depth predicts that the feature size can be down to ~15 nm at the film thickness of ~10 nm. A nano-grating is fabricated, which demonstrates desirable beam diffraction performance. This nano-scale resolution would be highly attractive for next-generation laser nano-litho graphy in far field and in ambient air.

Integrating 2D layered materials with 3D bulk materials as van der Waals heterostructures for photodetections: Current status and perspectives - Weijie Liu, Yiye Yu, Meng Peng, Zhihua Zheng, Pengcheng Jian, Yang Wang, Yuanchen Zou, Yongming Zhao, Fang Wang, Feng Wu, Changqing Chen, Jiangnan Dai, Peng Wang, Weida Hu (InfoMat, 2023)
Abstract In the last decade, two‐dimensional layered materials (2DLMs) have been drawing extensive attentions due to their unique properties, such as absence of surface dangling bonds, thickness‐dependent bandgap, high absorption coefficient, large specific surface area, and so on. But the high‐quality growth and transfer of wafer‐scale 2DLMs films is still a great challenge for the commercialization of pure 2DLMs‐based photodetectors. Conversely, the material growth and device fabrication technologies of three‐dimensional (3D) semiconductors photodetectors tend to be gradually matured. However, the further improvement of the photodetection performance is limited by the difficult heterogeneous integration or the inferior crystal quality via heteroepitaxy. Fortunately, 2D/3D van der Waals heterostructures (vdWH) combine the advantages of the two types of materials simultaneously, which may provide a new platform for developing high‐performance optoelectronic devices. Here, we first disc uss the unique advantages of 2D/3D vdWH for the future development of photodetection field and simply introduce the structure categories, working mechanisms, and the typical fabrication methods of 2D/3D vdWH photodetector. Then, we outline the recent progress on 2D/3D vdWH‐based photodetection devices integrating 2DLMs with the traditional 3D semiconductor materials, including Si, Ge, GaAs, AlGaN, SiC, and so on. Finally, we highlight the current challenges and prospects of heterointegrating 2DLMs with traditional 3D semiconductors toward photodetection applications. image

Progress and Insight of Van der Waals Heterostructures Containing Interlayer Transition for Near Infrared Photodetectors - Waqas Ahmad, Liang Pan, Karim Khan, Lingpu Jia, Qiandong Zhuang, Zhiming Wang (Advanced Functional Materials, 2023)
Abstract Van der Waals (vdWs) heterostructures enable bandgap engineering of different 2D materials to realize the interlayer transition via type‐II band alignment leading to broaden spectrum that is beyond the cut‐off wavelength of individual 2D materials. Interlayer transition has a significant effect on the optoelectronic performance of vdWs heterostructure devices, and strong interlayer transition in 2D vdWs heterojunction is always demandable for sufficient charge transfer and rapid speed response. Herein, a state‐of‐the‐art review is presented on recent progress on interlayer transition in vdWs heterostructures for near‐infrared (NIR) photodetectors. First, the general synthesis techniques for vdWs heterostructures, band alignments in the vdWs heterostructures are provided. Then, the mechanism of interlayer transition in vdWs heterostructure and recent progress on interlayer transition in vdWs heterostructures for NIR photodetectors are summarized. Afterward, some worthy applicat ions of NIR photodetectors are reviewed in related areas of this topic. At the last, an outlook, challenges, and future research directions of vdWs heterostructures for photodetectors at broaden response spectrum are presented.

The ferro-pyro-phototronic effect for high-performance self-powered photodetectors - Ampattu Ravikumar Jayakrishnan, José Silva, Katarzyna Gwóźdź, M. J. M. Gomes, Robert L. Z. Hoye, Judith L. MacManus‐Driscoll (Nano Energy, 2023)
Self-powered photodetectors are advantageous over conventional photodetectors because they can have outstanding performance in the absence of an external power source, which is important for a range of applications, including in the Internet of Things. Current research has demonstrated different types of self-powered photodetectors utilizing the photovoltaic effect, pyroelectric effect, piezoelectric effect, and synergic effects, such as the piezo-phototronic and pyro-phototronic effects. Such effects have been demonstrated in standard semiconductors, in hybrid inorganic-organic halide perovskites and in all inorganic perovskites. Very recently, a novel type of self-powered photodetector exploring the coupling between the photovoltaic, the pyroelectric and the ferroelectric effects (i.e., ferro-pyro-phototronic effect) has attracted great interest, owing to the excellent photo current response achieved with this triple coupling. The ferro-pyro-phototronic effect can therefore be an imp ortant route towards improving the performance of self-powered photodetectors. Since ferroelectricity has the potential to bring revolutionary changes in many contemporary technologies, including non-volatile memory, solar cells, field effect transistors, energy storage, and energy harvesters, it is worthwhile exploring in more detail how the ferroelectric effect enhances the triple coupling. Thus, this focus review covers the research conducted so far on the ferro-pyro-phototronic effect, discussing recent progress on the development of self-powered photodetectors based on this effect, and also highlighting current challenges and potential solutions for using these devices in real-world applications.

Paper-based ZnO self-powered sensors and nanogenerators by plasma technology - Xabier García‐Casas, Francisco J. Aparicio, J. A. Budagosky, Ali Ghaffarinejad, Noel Orozco-Corrales, Kostya Ostrikov, Juan R. Sánchez‐Valencia, Ángel Barranco, Ana Borrás (Nano Energy, 2023)
Nanogenerators and self-powered nanosensors have shown the potential to power low-consumption electronics and human-machine interfaces, but their practical implementation requires reliable, environmentally friendly and scalable, processes for manufacturing and processing. Furthermore, the emerging flexible and wearable electronics technology demands direct fabrication onto innovative substrates such as paper and plastics typically incompatible with high process temperatures. This article presents a plasma synthesis approach for the fabrication of piezoelectric nanogenerators (PENGs) and self-powered sensors on paper substrates. Polycrystalline ZnO nanocolumnar thin films are deposited by plasma-enhanced chemical vapour deposition on common paper supports using a microwave electron cyclotron resonance reactor working at room temperature yielding high growth rates and low structural and interfacial stresses. Applying Kinetic Monte Carlo simulation, we elucidate the basic shadowing mechan ism behind the characteristic microstructure and porosity of the ZnO thin films, relating them to an enhanced piezoelectric response to periodic and random inputs. The piezoelectric devices are assembled by embedding the ZnO films in polymethylmethacrylate (PMMA) and using Au thin layers as electrodes in two different configurations, namely laterally and vertically contacted devices. We present the response of the laterally connected devices as a force sensor for low-frequency events with different answers to the applied force depending on the impedance circuit, i.e. load values range, a behaviour that is theoretically analyzed. The characterization of the vertical devices in cantilever-like mode reaches instantaneous power densities of 80 nW/cm2 with a mean power output of 20 nW/cm2. Besides, we analyze their actual-scenario performance by activation with a fan and handwriting. Overall, this work demonstrates the advantages of implementing plasma deposition for piezoelectric films to develop robust, flexible, stretchable, and enhanced-performance nanogenerators and self-powered piezoelectric sensors compatible with inexpensive and recyclable supports.

General low-temperature growth of two-dimensional nanosheets from layered and nonlayered materials - Biao Qin, Muhammad Zeeshan Saeed, Qiuqiu Li, Manli Zhu, Ya Feng, Ziqi Zhou, Jingzhi Fang, Mongur Hossain, Zucheng Zhang, Yucheng Zhou, Ying Huangfu, Rong Song, Jingmei Tang, Bailing Li, Jialing Liu, Di Wang, Kun He, Hongmei Zhang, Ruixia Wu, Bei Zhao (Nature Communications, 2023)
Most of the current methods for the synthesis of two-dimensional materials (2DMs) require temperatures not compatible with traditional back-end-of-line (BEOL) processes in semiconductor industry (450 °C). Here, we report a general BiOCl-assisted chemical vapor deposition (CVD) approach for the low-temperature synthesis of 27 ultrathin 2DMs. In particular, by mixing BiOCl with selected metal powders to produce volatile intermediates, we show that ultrathin 2DMs can be produced at 280-500 °C, which are ~200-300 °C lower than the temperatures required for salt-assisted CVD processes. In-depth characterizations and theoretical calculations reveal the low-temperature processes promoting 2D growth and the oxygen-inhibited synthetic mechanism ensuring the formation of ultrathin nonlayered 2DMs. We demonstrate that the resulting 2DMs exhibit electrical, magnetic and optoelectronic properties comparable to those of 2DMs grown at much higher temperatures. The general low-temperature preparation of ultrathin 2DMs defines a rich material platform for exploring exotic physics and facile BEOL integration in semiconductor industry.

Enabling metallic behaviour in two-dimensional superlattice of semiconductor colloidal quantum dots - Ricky Dwi Septianto, Retno Miranti, Tomoka Kikitsu, Takaaki Hikima, Daisuke Hashizume, Nobuhiro Matsushita, Yoshihiro Iwasa, Satria Zulkarnaen Bisri (Nature Communications, 2023)
Abstract Semiconducting colloidal quantum dots and their assemblies exhibit superior optical properties owing to the quantum confinement effect. Thus, they are attracting tremendous interest from fundamental research to commercial applications. However, the electrical conducting properties remain detrimental predominantly due to the orientational disorder of quantum dots in the assembly. Here we report high conductivity and the consequent metallic behaviour of semiconducting colloidal quantum dots of lead sulphide. Precise facet orientation control to forming highly-ordered quasi-2-dimensional epitaxially-connected quantum dot superlattices is vital for high conductivity. The intrinsically high mobility over 10 cm 2 V −1 s −1 and temperature-independent behaviour proved the high potential of semiconductor quantum dots for electrical conducting properties. Furthermore, the continuously tunable subband filling will enable quantum dot superlattices to be a future platform for emerging phy sical properties investigations, such as strongly correlated and topological states, as demonstrated in the moiré superlattices of twisted bilayer graphene.

Integration of microbattery with thin-film electronics for constructing an integrated transparent microsystem based on InGaZnO - Bin Jia, Chao Zhang, Min Liu, Zhen Li, Jian Wang, Li Zhong, Chuanyu Han, Ming Qin, Xiaodong Huang (Nature Communications, 2023)
Abstract A full integration of miniaturized transparent energy device (lithium-ion battery), electronic device (thin-film transistor) and sensing device (photodetector) to form a monolithic integrated microsystem greatly enhances the functions of transparent electronics. Here, InGaZnO is explored to prepare the above devices and microsystem due to its multifunctional properties. A transparent lithium-ion battery with InGaZnO as anode (capacity~9.8 μAh cm −2 ) is proposed as the on-chip power source. Then, thin-film transistor with InGaZnO as channel (mobility~23.3 cm 2 V −1 s −1 ) and photodetector with InGaZnO as photosensitive layer (responsivity~0.35 A W −1 ) are also prepared on the substrate for constructing an fully integrated transparent microsystem. Each device displays acceptable performance. Moreover, alternating-current signals can be successfully charged into the lithium-ion battery by using the thin-film transistor as the on-chip rectifier and also the photodetector works well by using the charged battery as the on-chip power, demonstrating collaborative capabilities of each device to achieve systematic functions.

Chiroptical Synaptic Heterojunction Phototransistors Based on Self‐Assembled Nanohelix of π‐Conjugated Molecules for Direct Noise‐Reduced Detection of Circularly Polarized Light - Hanna Lee, Jun Ho Hwang, Seung Ho Song, Hyemi Han, Seo‐Jung Han, Bong Lim Suh, Kahyun Hur, Jihoon Kyhm, Jongtae Ahn, Jeong Ho Cho, Do Kyung Hwang, Eunji Lee, Changsoon Choi, Jung Ah Lim (Advanced Science, 2023)
Abstract High‐performance chiroptical synaptic phototransistors are successfully demonstrated using heterojunctions composed of a self‐assembled nanohelix of a π‐conjugated molecule and a metal oxide semiconductor. To impart strong chiroptical activity to the device, a diketopyrrolopyrrole‐based π‐conjugated molecule decorated with chiral glutamic acid is newly synthesized; this molecule is capable of supramolecular self‐assembly through noncovalent intermolecular interactions. In particular, nanohelix formed by intertwinded fibers with strong and stable chiroptical activity in a solid‐film state are obtained through hydrogen‐bonding‐driven, gelation‐assisted self‐assembly. Phototransistors based on interfacial charge transfer at the heterojunction from the chiroptical nanohelix to the metal oxide semiconductor show excellent chiroptical detection with a high photocurrent dissymmetry factor of 1.97 and a high photoresponsivity of 218 A W −1 . The chiroptical phototransistor demonstrate s photonic synapse‐like, time‐dependent photocurrent generation, along with persistent photoconductivity, which is attributed to the interfacial charge trapping. Through the advantage of synaptic functionality, a trained convolutional neural network successfully recognizes noise‐reduced circularly polarized images of handwritten alphabetic characters with better than 89.7% accuracy.

Field‐Induced Transparent Electrode‐Integrated Transparent Solar Cells and Heater for Active Energy Windows: Broadband Energy Harvester - Malkeshkumar Patel, Sangho Kim, Joondong Kim (Advanced Science, 2023)
Abstract Invisible power generation by natural and artificial light enables sustainability by onsite‐power deployment, lower cost, and minimal burden on the built environment. However, dark, opaque photovoltaics limit light utilization in a transparent way. Herein, it is proposed that the active energy window (AEW) invisibly features power production, providing higher freedom for onsite power generators in window objects without limiting human vision. The AEW has a transparent photovoltaic (TPV) for onsite power and a transparent heater (TH) to remove the effects of shadows from snow and recover the power lost. Moreover, a heating function is applied to remove the effects of weathering related to snow. The proposed prototype integrates a TPV‐TH, offering ultraviolet (UV)‐blocking, daylighting, thermal comfort, and onsite power with a power conversion efficiency of 3% (AM1.5G). Field‐induced transparent electrodes are applied to the TPV‐TH and designed considering the AEW. Owing to thes e electrodes, the AEW ensure a wide field‐of‐view without optical dead zones, ensuring see‐through vision. The first TPV‐TH integration is performed into a 2 cm 2 ‐window that generates onsite power of 6 mW and has an average visible transmittance of ≈39%. It is believed that light can be utilized with comfort through the AEW in self‐sustainable buildings and vehicles.

Functionalization of Indium Oxide for Empowered Detection of CO2 over an Extra-Wide Range of Concentrations - Arianna Rossi, Barbara Fabbri, Elena Spagnoli, Andrea Gaiardo, Matteo Valt, Matteo Ferroni, Matteo Ardit, Soufiane Krik, Andrea Pedrielli, L. Vanzetti, V. Guidi (ACS Applied Materials & Interfaces, 2023)
High Resolution Image Download MS PowerPoint Slide Carbon capture, storage, and utilization have become familiar terms when discussing climate change mitigation actions. Such endeavors demand the availability of smart and inexpensive devices for CO 2 monitoring. To date, CO 2 detection relies on optical properties and there is a lack of devices based on solid-state gas sensors, which can be miniaturized and easily made compatible with Internet of Things platforms. With this purpose, we present an innovative semiconductor as a functional material for CO 2 detection. A nanostructured In 2 O 3 film, functionalized by Na, proves to enhance the surface reactivity of pristine oxide and promote the chemisorption of even rather an inert molecule as CO 2 . An advanced operando equipment based on surface-sensitive diffuse infrared Fourier transform is used to investigate its improved surface reactivity. The role of sodium is to increase the concentration of active sites such as oxygen vacancies and, in turn, to strengthen CO 2 adsorption and reaction at the surface. It results in a change in film conductivity, i.e., in transduction of a concentration of CO 2 . The films exhibit excellent sensitivity and selectivity to CO 2 over an extra-wide range of concentrations (250–5000 ppm), which covers most indoor and outdoor applications due to the marginal influence by environmental humidity.

Unleashing the Power of Quantum Dots: Emerging Applications from Deep‐Ultraviolet Photodetectors for Brighter Futures - Taehyun Park, Dong Hyun Lee, Jaehyun Hur, Hocheon Yoo (Advanced Optical Materials, 2023)
Abstract Since their discovery in 1981, quantum dots (QDs) have been the center of attention in optoelectronic fields owing to their excellent properties such as clearly discrete band structure, high luminous efficiency, and tunable energy bandgap via dot size control. Among them, the bandgap increase characteristic based on the quantum confinement effect opens a new horizon in the field of deep ultraviolet photodetectors (DUV PDs). Emerging applications such as risk monitoring, wireless optical communication, and chemical sensing with extremely low environmental interference raise the significance of DUV PDs. Nonetheless, the limited material selection for DUV absorption has been the main obstacle for further applications. Along this line, this review systematically revisits the recent advances in QD‐based DUV PDs, using bandgap‐widened QDs, with a focus on the synthetic method, device architecture, and interactions among constituent components. Various QDs categorized into carbon, ox ide, sulfide, and nitride are reviewed with the specific characteristics of each substance. The future prospects of QD‐based DUV PDs in terms of practical applications and the current challenges are discussed.

Review on III–V Semiconductor Nanowire Array Infrared Photodetectors - Ziyuan Li, Zeyu He, Chenyang Xi, Fanlu Zhang, Longsibo Huang, Yang Yu, Hark Hoe Tan, C. Jagadish, Lan Fu (Advanced Materials Technologies, 2023)
Abstract In recent years, III–V semiconductor nanowires have been widely investigated for infrared photodetector applications due to their direct and suitable bandgap, unique optical and electrical properties, flexibility in device design and to create heterostructures, and/or grow on a foreign substrate such as Si with more effective strain relaxation compared with planar structures. In particular, vertically aligned and ordered nanowire arrays have emerged as a promising photodetector platform, since their geometry‐related light absorption and carrier transport properties can be tailored to achieve high photodetector performance and new functionalities. In this article, the state‐of‐the‐art progress in the development of various types of infrared photodetectors based on III–V semiconductor nanowire arrays is reviewed. The nanowire synthesis/fabrication methods are introduced briefly at first, followed by discussions on the working principle and device performance of various types of nanowire array‐based photodetectors and their emerging applications. Finally, we analyze the challenges and present the perspectives for the development of future low‐cost, large‐scale, high‐performance nanowire array infrared photodetectors for practical applications.

AgSbTe2 semi-nanocrystalline thin films as a multifunctional platform for optoelectronic and diode applications - Ruhani Ibrahim, Talaat A. Hameed, Sylvain Vedraine (Ceramics International, 2023)

Recent Advances in Materials, Structures, and Applications of Flexible Photodetectors - Genjie Yang, Jiyu Li, Mengge Wu, Xinge Yu, Junsheng Yu (Advanced Electronic Materials, 2023)
Abstract Flexible photodetectors (FPDs), which provide excellent advantages such as great wearability, portability, even implantability, have attracted tremendous interest in wearable healthcare monitoring, bendable imaging sensors, portable optical communication, etc. Recently, organic and perovskite‐based photoactive materials have been considered promising candidates for FPDs due to their superior optoelectronic performance, appealing mechanical flexibility, low‐temperature solution processability, and cost‐effectiveness. In this review, the milestone progress of organic, perovskite, and organic‐perovskite hybrid‐based FPDs and their applications in artificial intelligence are summarized. First, a brief introduction of device configurations, working principles, and key parameters for FPDs are presented. Subsequently, functional materials in FPDs, especially flexible photoactive materials of organic, perovskite, and organic‐perovskite hybrids, are summarized and analyzed. More import antly, representative applications of FPDs are summarized, including wearable healthcare monitoring, imaging sensors, and optical communication. The outlook and challenges for the field are proposed at the end. The purpose of this review is to not only elaborate on the fundamental design principles of FPDs, but also serve as a roadmap for next‐generation artificial intelligence sensing technologies.

A dual-mode image sensor using an all-inorganic perovskite nanowire array for standard and neuromorphic imaging - Zhenghao Long, Yucheng Ding, Xiao Qiu, Yu Zhou, Shivam Kumar, Zhiyong Fan (Journal of Semiconductors, 2023)
Abstract The high-density, vertically aligned retinal neuron array provides effective vision, a feature we aim to replicate with electronic devices. However, the conventional complementary metal-oxide-semiconductor (CMOS) image sensor, based on separate designs for sensing, memory, and processing units, limits its integration density. Moreover, redundant signal communication significantly increases energy consumption. Current neuromorphic devices integrating sensing and signal processing show promise in various computer vision applications, but there is still a need for frame-based imaging with good compatibility. In this study, we developed a dual-mode image sensor based on a high-density all-inorganic perovskite nanowire array. The device can switch between frame-based standard imaging mode and neuromorphic imaging mode by applying different biases. This unique bias-dependent photo response is based on a well-designed energy band diagram. The biomimetic alignment of nanowires ensures the potential for high-resolution imaging. To further demonstrate the imaging ability, we conducted pattern reconstruction in both modes with a 10 × 10 crossbar device. This study introduces a novel image sensor with high compatibility and efficiency, suitable for various applications including computer vision, surveillance, and robotics.

Recent advances in single crystal narrow band-gap semiconductor nanomembranes and their flexible optoelectronic device applications: Ge, GeSn, InGaAs, and 2D materials - Shu An, Hyun Jung Park, Munho Kim (Journal of Materials Chemistry C, 2023)
Flexible optoelectronics have attracted much attention in recent years for their potential applications in healthcare and wearable devices.

Nanogenerators and piezotronics: From scientific discoveries to technology breakthroughs - Zhong Lin Wang (MRS Bulletin, 2023)
Abstract Nanogenerators is a field that uses the piezoelectric and/or triboelectric effect for converting low-grade mechanical energy (termed as high-entropy energy) into electric power, with a great potential for applications in the Internet of Things, self-powered sensors, robotics, medical science, and even artificial intelligence. Piezotronics is a field that utilizes the piezoelectric polarization in third-generation semiconductors for controlling the charge-carrier transport in semiconductor devices. These two fields were first coined by Wang’s group in 2006 and 2007, respectively. This article reviews the background and initial ideas based on which we introduced the following original discoveries and effects: piezoelectric nanogenerators; triboelectric nanogenerators; self-powered sensor; hybrid cell; nano energy; high-entropy energy; piezotronics; and piezo-phototronics. As inspired by these original discoveries, the current technologies developed based on the scientific discov eries of nanogenerators and piezotronics are also reviewed. Graphical abstract

Binary solvent engineering for small-molecular organic semiconductor crystallization - Zhengran He, Ziyang Zhang, Kyeiwaa Asare‐Yeboah, Sheng Bi (Materials Advances, 2023)
This article reviews the synergistic effects of engineering binary solvents on the crystallization, morphology and charge transport of organic semiconductors.

The effect of annealing treatment on the structural and optical properties of nanostructured CuxO films obtained by 3D printing - Vladyslav Yevdokymenko, Oleksandr Dobrozhan, Roman Pshenychnyi, Anatoliy Opanasyuk, Yu. P. Gnatenko, А.P. Bukivskii, P.M. Bukivskij, R. Gamernyk, Oleksii Klymov, V. Muñoz‐Sanjosé, P. Ibañez-Romero, Ž. Gačević (Materials Science in Semiconductor Processing, 2023)
This work studies the effect of post-growth annealing on the structural and optical properties of copper oxide films. Thin films were obtained by 3D printing on glass substrates using ink based on a suspension of CuO nanoparticles. To optimize their structural characteristics and optical quality, the samples were subjected to thermal annealing for 30 min in an argon environment at different temperatures from 250 °C to 500 °C. The obtained samples were studied by scanning electron microscopy, X-ray diffraction, energy dispersive X-Ray, Raman, optical and photoelectric spectroscopy. Based on the obtained results, the main structural and substructural characteristics of the films were established, such as lattice parameters, unit cell volume, texture, sizes of coherent scattering regions, and the level of microdeformation, as well as their dependence on the annealing temperature. In addition, the nature of optical absorption, band gap energies for various types of electronic transitions, and the optical quality of the studied nanostructured copper oxide films were determined. It was shown that CuO films annealed at 350 °C have the best crystalline and optical quality. It was established that at an annealing temperature above 400 °C, a phase transition from the tenorite phase to the cuprite phase is observed. At the same time, a change in the films' substructural characteristics is already observed at Ta = 400 °C. Optimal thermal annealing conditions of CuxO films for effective control of their phase composition have been established.

Sweat permeable and ultrahigh strength 3D PVDF piezoelectric nanoyarn fabric strain sensor - Fan W, Lei R, Dou H, Wu Z, Lu L, Wang S, Liu X, Chen W, Rezakazemi M, Aminabhavi TM, Li Y, Ge S. (Nature Communications, 2024)
Commercial wearable piezoelectric sensors possess excellent antiinterference stability due to their electronic packaging. However, this packaging renders them barely breathable and compromises human comfort. To address this issue, we develop a PVDF piezoelectric nanoyarns with an ultrahigh strength of 313.3 MPa, weaving them with different yarns to form threedimensional piezoelectric fabric (3DPF) sensor using the advanced 3D textile technology. The tensile strength (46.0 MPa) of 3DPF exhibits the highest among the reported ﬂexible piezoelectric sensors. The 3DPF features antigravity unidirectional liquid transport that allows sweat to move from the inner layer near to the skin to the outer layer in 4 s, resulting in a comfortable and dry environment for the user. It should be noted that sweating does not

MWCNTs/C60 “Grape-like” Nanostructures for Enhancing Piezoelectric Performance in PVDF Nanofibers through Constructing Localized Conductive Domains (ACS Applied Electronic Materials, 2024)
Polyvinylidene fluoride (PVDF) piezoelectric nanofibers gain significant attention for flexible electronic devices, yet their low piezoelectric conversion efficiency remains a critical barrier to broader application. In this study, multiwalled carbon nanotubes (MWCNTs) are combined with fullerene (C60) to form a distinctive “grape-like” nanostructure (MC), which is then embedded into the PVDF matrix via electrospinning to produce PVDF/MC composite nanofibers. The incorporation of MC increases the β-phase content of the PVDF nanofibers by 11.07%, enhancing their piezoelectric properties, and also acts as localized conductive domains and stress concentration centers, synergistically boosting the output performance of the piezoelectric devices. Consequently, piezoelectric devices based on PVDF/MC-3 wt % composite nanofibers exhibit voltage and current outputs 559.1% and 1382.8% higher than those of pure PVDF, respectively. This innovative strategy of leveraging “grape-like” nanostructures to enhance PVDF’s piezoelectric performance represents a promising pathway toward achieving efficient energy conversion in piezoelectric materials.

Unleashing the Potential: Strategies for Enhancing Performance of Electrospun PVDF-Based Piezoelectric Nanofibrous Membranes (Fibers and Polymers, 2024)
In recent years, driven by the pressing demand for sustainable energy solutions, polyvinylidene fluoride (PVDF), a promising piezoelectric material, has garnered considerable attention for its application in energy-harvesting devices. PVDF stands out as the material of choice in piezoelectric generator technology owing to its remarkable flexibility, superior processability, long-term stability, and biocompatibility. Nevertheless, PVDF-based generators exhibit inferior piezoelectric responses compared to traditional piezoelectric ceramic materials, thereby constraining their performance in large-scale deployments. To address this limitation, researchers have been exploring innovative strategies to enhance the piezoelectric properties of PVDF. Among these, electrospinning technology emerges as a pivotal approach due to its ability to impart mechanical stretching and in situ polarization to the polymer during fabrication. This paper comprehensively reviews recent advancements in optimizin g the output performance of PVDF-based piezoelectric nanofiber membranes through the integration of filler doping technology with electrospinning. We delve into the effects of various filler types on the properties of electrospun PVDF-based piezoelectric nanofiber membranes and explore their underlying mechanisms. These fillers significantly bolster the output performance of PVDF-based piezoelectric devices by augmenting PVDF's piezoelectric activity, fostering dipole orientation, and elevating the dielectric constant. Notably, the incorporation of fillers not only elevates the piezoelectric coefficient but also optimizes the microstructure, facilitating an efficient conversion between mechanical and electrical energy. Furthermore, we envision the promising application prospects of PVDF piezoelectric nanofibers in cutting-edge fields, such as health monitoring, environmental monitoring, and energy-harvesting systems. These domains urgently require piezoelectric materials that combine h igh sensitivity, stability, and cost-effectiveness, where PVDF-based piezoelectric nanofibers, with their distinctive advantages, are poised to demonstrate significant application potential and societal value.

Electrospinning of porous polyvinylidene fluoride microspheres alloyed fibrous membrane with enlarged strain for efficient piezoelectric energy harvesting (Journal of Polymer Science, 2024)
Abstract Piezoelectric energy harvesters (PEHs) developed from electrospun polyvinylidene fluoride (PVDF) fibers offer flexibility and superior piezoelectric output, making them promising for self‐powered systems and sensors. Nonetheless, the electromechanical conversion efficiency of conventional electrospun PVDF fibers is impeded by their limited pressure‐strain range. Herein, elastic porous PVDF microspheres are introduced in‐situ via electrospinning to craft a piezoelectric membrane with higher compressive strain. The PVDF microspheres are uniformly embedded between the fibers in a sandwich fashion, and their dimension is easily tunable by varying spinning solution's concentration. Moreover, the micropores on the PVDF microspheres created by removing pre‐mixed SiO 2 template not only elevates the β crystal content of PVDF to 82.19%, but also improves the compressibility, significantly boosting the piezoelectric output. The microsphere alloyed PVDF PEH delivers a piezoelectric outpu t of 33.0 V and a power density of 8 μW/cm 2 , over 5.8 times that of conventional electrospun PVDF membrane, and can consistently charge lithium‐ion batteries. Our research unveils a novel strategic path to modify fiber structured PEHs, advancing their applications in self‐powered systems.

Fully Transparent Flexible Piezoelectric Sensing Materials Based on Electrospun PVDF and Their Device Applications (Advanced Materials Technologies, 2024)
Abstract Advanced transducer materials have become increasingly important with the rapid development of the internet of things and flexible electronics. Herein, fully transparent flexible polyvinylidene fluoride/polydimethylsiloxane (PVDF/PDMS) composite piezoelectric films are fabricated using scrape coating techniques based on electrospun PVDF nanofiber films. Compared to the electrospun PVDF, the PVDF/PDMS not only owns high transparency and a more uniform and stable structure but also has superior piezoelectric properties. Based on the electrospun PVDF and the PVDF/PDMS films, flexible piezoelectric sensors are developed, which can effectively detect weak mechanical signals including finger tapping and bending signals, radial artery pulses, and environmental sound signals. The PVDF/PDMS sensor performs better than the electrospun PVDF sensor and presents great potential for applications in flexible sensors and transducers. Especially, thanks to their high transparency, the PVDF/PDM S composite piezoelectric films lend themselves easily to application fields requiring transparent sensors such as imperceptible sensors and human‐machine interfaces, display devices, electronic skins, intelligent windows, etc.

Re-usable Cd0.9Zn0.1S-ZnO@C/PVDF piezo-photocatalytic film with exceptional hydrogen evolution capability triggered by the synergetic advantages of piezoelectricity and S-Scheme heterojunction - Ping Su, Dong Zhang, Minghui Zhu, Tengteng Liang, Nan Yang, Huaihao Zhao, Dafeng Zhang, Junchang Liu, Peiqing Cai, Xipeng Pu (Journal of Energy Chemistry, 2024)
Piezoelectric materials have advantages of fine-tuning photocatalytic performance through harvesting mechanical energy and open a new avenue in facilitating green catalytic reaction. Herein, polyvinylidene fluoride (PVDF), a flexible piezoelectric material, was introduced to synthesize a novel Cd 0.9 Zn 0.1 S- ZnO@C/PVDF (CZS-ZO@C/PVDF) piezo-photocatalytic film by spin coating and immersion phase conversion method. Benefiting from the piezoelectricity of PVDF and the internal electric field (IEF) of CZS-ZO@C Step-scheme (S-Scheme) heterojunction, CZS-ZO@C/PVDF was able to induce a hydrogen generation rate of 34.9 mmol g _1 h _1 activated by ultrasound and visible light (U -L), which is -17.5 times of Cd 0.9 Zn 0.1 S/ PVDF (CZS/PVDF) and -7.4 times of the photocatalysis rate activated by visible light only (L). Piezoelectric measurements and COMSOL simulation illustrated the excellent piezoelectricity of CZSZO@C/PVDF film, which exhibits a piezoelectric coefficient ( d 33 ) of 9.9 pm V _ 1 and a piezoelectric potential of 874 mV (under 0.5 MPa). The reaction mechanism for the exceptional piezo-photocatalytic performance was finally disclosed through density functional theory (DFT) calculation and electrochemical tests. This study enriches the application scope of piezoelectric materials in sustainable energy catalysis and provides a new direction to develop efficient piezoelectric photocatalysts. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

All‐organic shell–core PVDF/PMMA composite fiber films with enhanced piezoelectric performance for flexible sensing and energy harvesting (Journal of Applied Polymer Science, 2024)
Abstract The demand for self‐powered sensing technology and energy harvesting system necessitates high‐performance and flexible piezoelectric materials. This paper presents a novel approach utilizing coaxial electrospinning to fabricate all‐organic PVDF/PMMA piezoelectric fiber films with a shell–core structure. The resulting fiber films, cut into 2 × 2 cm 2 square pieces and hot‐pressed every three pieces, demonstrate enhanced piezoelectric properties while retaining high flexibility. The interaction between the CO bonds in the PMMA polymer and the CH 2 in PVDF promotes the arrangement of F atoms in PVDF, enhancing the content of the piezoelectric active phase. Additionally, the coaxial electrospinning process fosters vertically oriented hydrogen bonds between PVDF and PMMA, augmenting cross‐linking and improving mechanical properties. Notably, when the PVDF to PMMA layer volume ratio is 5:1, the piezoelectric coefficient (| d 33 |) of the composite fiber film exhibits a significan t 60% increase from 10 pC N −1 in neat PVDF to 16 pC N −1 . This research holds substantial promise for applications in self‐powered sensing and energy harvesting piezoelectric materials.

Enhancing the efficiency of PVDF-based piezoelectric catalysis through water-induced polarization and a micro-nano-composite strategy (Nanoscale, 2024)
, which is ∼9-fold and ∼134-fold higher than those of untreated PVDF and previously reported PVDF-based piezoelectric catalysts, respectively. This work paves the way for the development of highly efficient PVDF-based piezoelectric catalysts, thereby offering valuable insights for the advancement of mechanically driven catalysis in the environmental, energy, and chemical sectors.

Polyvinylidene Fluoride Nanocomposites as Piezoelectric Nanogenerator: Properties, Fabrication and Market Applications (Advanced Engineering Materials, 2024)
Depletion of fossil fuels and increase in pollution through chemical batteries trigger the development of self‐powered devices based on flexible piezoelectric nanogenerators (PNG). Biocompatible piezoelectric polyvinylidene fluoride (PVDF) nanocomposites merged with piezoelectric fillers like ZnO, KNN, and BaTiO 3 reproduce amended piezoelectric current, contributing to the safe application as biosensors and flexible industrial devices. Optimized loading, precise selection, and variating the surface chemistry of piezoelectric filler, along with fabrication schemes comprising different structural configurations of composites, considerably influence its potential for application as an energy harvester. Also, optimized processing condition upgrades dielectric constant and energy storage density, and reduces dielectric loss, thereby plummeting energy dissipation even after prolonged usage. Consequently, this article reviews the principles, properties, fabrication techniques, and market app lication of PVDF composites. A detailed relationship of significant electrical properties of PVDF composites with its fabrication methods and (piezoelectric parameters of fabricated PVDF composites with reported real‐life wearable, implantable, and industrial‐based portable piezoelectric devices are discussed in detail along with tabulated data for a clear understanding of structure–property relationship. Again, the market strategy for establishing flexible PVDF composite as a PNG has been discussed. A piece of in‐depth knowledge is provided for procuring affordable futuristic large‐scale PVDF‐based nanogenerators exhibiting affordable market worth.

Enhance the piezoelectricity of poly(vinylidene fluoride) through co-crystal with polycaprolactone (Composites Science and Technology, 2024)
The strategies of solid solution and doping have been well-established obtaining high piezoelectric ceramics, achieving a significant increase in the piezoelectric coefficient. Nevertheless, there is a paucity of research investigating this strategy in polymer piezoelectric materials. In this work, we present a novel approach to co- crystal formation between polycaprolactone (PCL) and poly(vinylidene fluoride) (PVDF), which markedly enhances the piezoelectricity of PVDF. The formation of a co-crystal results in a notable reduction in the crystal size of PVDF, an increase in the interface between the crystalline and amorphous regions, and the directional arrangement of dipoles under an electric field. The piezoelectric coefficient of the 3 % PCL/PVDF film is approximately twice that of the commercial PVDF film (22.0 pC/N), and the sensor device exhibits favorable linear sensing characteristics. The present study proposes a novel strategy for the development of films with exceptional pie zoelectric properties.

Ionic Surfactant-Assisted PVDF Nanofabrics with High Dielectric and Excellent Piezoelectric Performance - Khalifa, Mohammed; Lammer, Herfried; Anandhan, S. (FIBERS AND POLYMERS, 2024)
Flexible dielectrics and piezoelectric sensors have attracted a number of applications in advanced electronic systems. In this regard, poly(vinylidene fluoride) (PVDF) is considered as a promising option due to its flexibility and ferroelectric properties. In this study, a highly flexible non-woven fabric was developed from electrospun PVDF nanofibers containing cationic and anionic surfactants. Cetrimonium bromide (CTAB) was used as a cationic surfactant, while sodium lauryl sulfate (SLS) was used as an anionic surfactant. The presence of cationic and anionic surfactants played a pivotal role in the production of finer fibers. PVDF-SLS nano-fabric exhibited oriented fibers, while PVDF-CTAB nano-fabric displayed randomly arranged fibers. PVDF-SLS-based nano-fabric displayed the highest beta-phase content of 98.2%, while PVDF-CTAB non-woven showed a beta-phase content of 91.6%. A significant improvement in the dielectric properties of PVDF nano-fabric was observed upon the addition of c ationic and anionic surfactants. Furthermore, PVDF-SLS nano-fabric demonstrated exceptional dielectric and piezoelectric properties, generating a piezoelectric voltage of similar to 19 V. In comparison, PVDF-CTAB nano-fabric exhibited a piezoelectric voltage of 12.5 V. The power density of PVDF improved significantly upon the addition of SLS surfactant. Such attributes position PVDF-SLS nanofabrics as valuable candidates for diverse applications, particularly in the field of piezoelectric sensors and energy storage devices. The research not only advances the understanding of optimizing PVDF nanofabrics, but also establishes a foundation for future exploration in the realm of flexible electronics.

Flexible electrospun PVDF/WO3 nanocomposite fibers for piezoelectric energy harvesting applications - Arul, N.; Suresh, M.; Satthiyaraju, M.; Babu, N. B. Karthik (POLYMER COMPOSITES, 2024)
The emerging field of energy harvesting depends on the electrically conductive materials that are highly flexible and deformable. The morphological, structural, thermal, mechanical, and piezoelectric output studies of electrospun polyvinylidene fluoride (PVDF) and PVDF/WO3 nanorods composite nanofibers were investigated for the piezoelectric energy harvesting applications. There is a significant enhancement in the piezoelectric beta phase after the addition of the WO3 nanorods into the PVDF. The elemental composition of the PVDF/WO(3 )nanorods composite nanofibers is confirmed by the W, O, F, and C elements. The thermal stability of the WO3 nanorods added composite nanofibers was increased up to 30(degrees)C in reference to TGA responses. Based on the mechanical test, the maximum tensile strength and modulus of elasticity were enhanced around by 220 and 246% for the WO3-integrated PVDF nanofibers. Furthermore, the piezoelectric coefficient of 18.98 pC/N is achieved for the composite PV DF nanofibers which are mainly due to the improvement of the electroactive beta phase. The piezoelectric energy harvesting responses were found an output voltage of 2.1 V based on the microstrain set-up. Thus, these WO3 nanorods incorporated PVDF nanofibers keep the great potential for the piezoelectric energy harvesting, wearable electronics and biomedical applications.PVDF/WO3 nanofibres for energy harvesting. image

A Facile Strategy to Achieve High Piezoelectric Performance in Electrospun Poly(Vinylidene Fluoride) Non-woven Nanofabrics - Khalifa, Mohammed; Kumar, Manish; Subramanian, Gokul; Anandhan, S. (Transactions on Electrical and Electronic Materials, 2024)
Poly(vinylidene fluoride) (PVDF) with its piezoelectric characteristics holds the potential to be the promising candidate in microdevices, sensors and actuators. In this study, a facile strategy was adopted to augment the electroactive β-phase of electrospun PVDF non-woven nanofabric. Electrospun PVDF non-woven fabric was mechanically stretched at different strain rates. SEM images revealed that upon stretching the non-woven fabric, the fibers tend to orient along the stretching direction. The fibers from the necked region were characterized to understand effect of stretching on the polymorphism, crystallinity and piezoelectric performance. The β-phase content of PVDF increased upon increasing the strain rate, while the degree of crystallinity decreased slightly. The highest β-phase content of 79% was achieved for electrospun PVDF nonwoven fabric stretched at 10 mm/min. Further, the piezoelectric performance of the stretched nanofabric was evaluated to assess its electroactive characte ristics. The piezoelectric performance of electrospun PVDF fabric was studied by imparting the pressure/load by one-finger tapping, hand pressure and dropping weight. The highest output voltage and current of 8.4 V and 249 nA, respectively were obtained from the electrospun PVDF non-woven stretched at 10 mm/min, which is almost 8 times higher than that of the unstretched PVDF non-woven. Given the flexibility, lightweight with good piezoelectric performance these electrospun PVDF non-woven fabrics could be a potential material for energy harvesting and self-powered nano-electronic devices.

High Performance Piezoelectric Nanogenerators Based on Polyvinylidene Fluoride-Graphene Nanoribbon Composite Thin Films - Adiguzel, Secil Peker; Ercan, Nevra (MACROMOLECULAR RAPID COMMUNICATIONS, 2024)
In this study, a highly efficient, sensitive, and lightweight piezoelectric nanogenerator (PENG) is developed using graphene nanoribbons (GNRs) incorporated into the polyvinylidene fluoride (PVDF) matrix. Unzipping multi-walled carbon nanotubes is an effective and scalable strategy for synthesizing graphene nanoribbons. The synthesized GNRs are employed to prepare nanometer-scale piezoelectric polymer composite films showing higher piezoelectric performance than neat PVDF. The impact of GNR concentration in the PVDF matrix on the electroactive phase content and piezoelectric properties of the composites is systematically investigated. X-ray diffraction (XRD) and Fourier-transformed infrared spectroscopy (FT-IR) analysis demonstrate an increase in the electroactive beta and gamma phases of PVDF by incorporating GNRs in the composites. With the optimized concentration of GNRs (1 wt%), the fabricated piezoelectric device can generate open-circuit voltage and an output power density of 26 V and 16.52 mu Wcm2, respectively. It is also found that the PVDF-GNR 1 nanogenerator can be used to generate electrical power by converting mechanical energy from different human activities such as wrist bending, palm tapping, and toe tapping. The findings indicate that (PVDF-GNR 1) PENG can be applied in self-powered portable and wearable electronic devices.Unzipping multi-walled carbon nanotube (MWCNT) is a highly efficient method to obtain graphene nanoribbon (GNR). Incorporation of GNR into polyvinylidene fluoride (PVDF) is found to be an effective approach to enhance the content of electroactive beta phase. PVDF-GNR 1 wt% nanogenerator can be used to generate electrical power by converting mechanical energy from different human activities such as wrist bending and toe-tapping. image

β-Phase Crystallinity, Printability, and Piezoelectric Characteristics of Polyvinylidene Fluoride (PVDF)/Poly(methyl methacrylate) (PMMA)/Cyclopentyl-Polyhedral Oligomeric Silsesquioxane (Cp-POSS) Melt-Compounded Blends - Edwards TR, Shankar R, Smith PGH, Cross JA, Lequeux ZAB, Kemp LK, Qiang Z, Iacano ST, Morgan SE. (ACS Applied Polymer Materials, 2024)
Poly(vinylidene fluoride) (PVDF) is a semicrystalline polymer that exhibits unique piezoelectric characteristics along with good chemical resistance and high thermal stability. Layerbased material extrusion (MEX) 3D printing of PVDF is desired to create complex structures with piezoelectric properties; however, the melt processing of PVDF typically directs the formation of the α crystalline allomorph, which does not contribute to the piezoelectric response. In this work, PVDF was compounded with poly(methyl methacrylate) (PMMA) and cyclopentylpolyhedral oligomeric silsesquioxane (Cp-POSS) nanostructured additives in binary and ternary blends to improve MEX printability while maintaining piezoelectric performance. Overall crystallinity and β phase content were evaluated and quantified using a combination of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and differential scanning calorimetry (DSC). Enhancement of MEX printability was measured by quantifyi ng the interlayer adhesion and warpage of printed parts. All blends studied contained a significant percentage of β allomorph, but it could be detected by ATR-FTIR only after the removal of a thin surface layer. Inclusion of 1% Cp-POSS and up to 10% PMMA in blends with PVDF improved interlayer adhesion (2.3−3.6x) and lowered warpage of MEX printed parts compared to neat PVDF. The blend of 1% Cp-POSS/1% PMMA/PVDF was demonstrated to significantly improve the quality of MEX printed parts while showing similar piezoelectric performance to that of neat PVDF (average piezoelectric coefficient 24 pC/N). MEX printing of PVDF blends directly into usable parts with significant piezoelectric performance while reducing the challenges of printing the semicrystalline polymer opens the potential for application in a number of high value sectors.

Effective-performance of inorganic and organic (barium zirconium titanate/polyvinylidene fluoride) piezoelectric composite for energy harvesting and self-powered smart IoT-based electronics - Fahad, Mohd; Waqar, Arbaz; Kim, Byungki (JOURNAL OF ALLOYS AND COMPOUNDS, 2024)
In the context of the rapidly advancing fields of energy harvesting and the Internet of Things (IoT), flexible piezoelectric materials have received significant attention for powering and providing sensing signals to electronic devices. In this study, piezoelectric barium zirconium titanate (BZT) material was synthesized via a solidstate reaction method at high temperatures. The synthesized BZT was incorporated as a filler in the PVDF polymer matrix to design a flexible piezoelectric device using a solvent-casting method. Structural analyses verified the formation of the tetragonal structure (P4mm) of BZT and the successful composite with PVDF. Piezoelectric properties of PVDF and BZT/PVDF were tested under mechanical force, revealing that the BZT/ PVDF composite exhibited higher voltage output compared to PVDF under applied load. Furthermore, the BZT/ PVDF composite demonstrated excellent stress tolerance and enhanced piezoelectric performance under varying loads. Notably, the BZT/PVD F composite showed impressive energy harvesting capabilities during finger tapping, storing electrical energy in capacitors, to power electronic watch, calculator, mini-speaker, and illuminating LEDs. The composite also exhibited potential for monitoring and harvesting energy from human motion. Additionally, BZT/PVDF was utilized as a smart lab alarm (SLA) system for the safety of human beings, enhancing safety in laboratories by signaling potential contact between BZT/PVDF and human beings in hazardous areas. These findings indicate the flexible BZT/PVDF composite as a promising solution for lead-free energy harvesting and self-powered smart IoT-based electronics.

Lead-Free Compositional Engineering to Induce Polar Phase in Polymeric Piezoelectric Host for Energy Harvesting Devices - Sharma, Vijay Bhan; Prajesh, Neetu; Sharma, Vaishnavi; Bhardwaj, Bhupesh; Singh, Mohit Kumar; Banappanavar, Gangadhar; Kadam, Ankur; Boomishankar, Ramamoorthy; Subramaniam, Chandramouli; Kabra, Dinesh (ACS APPLIED ELECTRONIC MATERIALS, 2024)
With the growing demand and environmental concerns regarding applied electronic materials, a shift toward lead-free piezoelectric materials has been seen since the past decade. Polyvinylene difluoride (PVDF) serves as a lead-free and ultralight-weight piezoelectric polymer for flexible self-powered sensors and actuators; however, it suffers from low energy harvesting efficiency (10-12 V maximum output at a typical pressure in the range of 10-20 N/cm(2) for pure PVDF) due to the dominance of the nonpolar alpha (alpha) phase. In this work, we developed a method of using the nonpolar alpha phase to show the performance of piezoelectric response surpassing the reported PVDF-TrFe (trifluoroethylene-grafted PVDF) by compositional engineering with the help of inorganic fillers. The energy harvesting capability of pure PVDF was increased by almost 180% with the help of filler materials such as barium titanate (BaTiO3 or BTO) at PVDF:BTO = 95:5 wt %. The local piezoelectric coefficient (d(33)) of these films was increased from 12 to 26 pm/V, which correlates well with structural and energy harvesting device (widely known as a piezoelectric nanogenerator, PENG) studies. Our investigations enable pure PVDF to be used in place of PVDF-TrFe, which is a cost-effective solution for energy harvesting devices.

Flexible PVDF/SiC/FeCl3 nanofiber membrane generators with synergistically enhanced piezoelectricity - Gong, Zhuowei; Qin, Jie; Liu, Ding; Lv, Shasha; Du, Yong; Zhang, Ting; Ke, Qinfei (NANO ENERGY, 2024)
Poly(vinylidene fluoride) (PVDF) is a renowned piezoelectric polymer, but its widespread application is hindered by its low fi phase content. This research presents the fabrication of PVDF/SiC, PVDF/FeCl3, and PVDF/SiC/FeCl3 composite nanofiber membranes via an electrospinning technique. Among these, the PVDF/SiC/FeCl3 composite nanofiber-based piezoelectric nanogenerator (PENG) exhibited the best output performance. This enhancement is primarily due to the synergistic effect of incorporating SiC and FeCl3 into the PVDF matrix, which significantly increases the fi phase content of PVDF, thereby enhancing the piezoelectric properties of the PENG. The flexible PENG arrays composed of PVDF/SiC/FeCl3 composite membranes hold great promise for use in smart socks for gait monitoring, particularly for early corrective measures in preschool children. This innovation is expected to have a significant impact on the fields of sports, medical monitoring, and other related areas.

Volumetric 3D-Printed Piezoelectric Polymer Films - Frick, Achidi; van Vliet, Wesley Alexander; Zukauskaite, Agne; Zywitzki, Olaf; Modes, Thomas; Kostenko, Alexander; von Hauff, Elizabeth (ADVANCED MATERIALS TECHNOLOGIES, 2024)
A novel additive manufacturing route using a tailored resin containing Poly(vinylidene fluoride) Trifluoroethylene (PVDF-TrFE) to 3D print piezoelectric films is demonstrated. Piezoelectric films are printed within 2 seconds in a single step by simultaneously focusing initiating and inhibiting excitations within the liquid resin to locally confine the photochemical reaction. The printed films are patterned with an array of holes with a diameter of 30 mu m and a pitch of 55 mu m. The piezoelectric response is homogeneous across the film, indicating that the print pattern does not impact the PVDF-TrFE microstructure. Although the printed films contain only a small volume fraction of PVDF-TrFE (3 wt.%), their piezoelectric response (d33 = 20.3 pC/N) is comparable to the highest literature values reported for PVDF-TrFE films. The printed PVDF-TrFE films are predominantly beta-phase, and no electrical poling, post-processing, piezoelectric or inorganic additives are used in the fabrication. Analysis using piezoresponse force microscopy (PFM) and scanning electron microscopy (SEM) reveals that the enhanced piezoelectric response is due to the preferential formation of oriented PVDF-TrFE phases during printing. These results demonstrate how the dedicated design of photoactive resins in combination with volumetric additive manufacturing can be applied to rapidly fabricate functional 3D structures.3D printing of piezoelectric PVDF-TrFE films from a photochemical reaction. The microstructure films are printed in 2s by exciting the photo-active resin with an initiating (go) and inhibiting (stop) excitation wavelength, respectively.image

The Micro-Capacitance Enhancement of Polyionic Liquids Grafted Onto Carbon Nanotubes on the Piezoelectric Properties of Poly(Vinylidene Fluoride) Films and Their Sensor Applications - Li, Suyue; Wang, Shiting; Ma, Wenzhong; Yang, Haicun; Cao, Zheng; Liu, Chunlin; Ye, Haimu (JOURNAL OF MACROMOLECULAR SCIENCE PART B-PHYSICS, 2024)
The increased micro-capacitance of a poly (vinylidene fluoride) (PVDF) matrix can effectively improve the piezoelectric properties of the composite material. This work used chemically modified carbon nanotubes (CNTs) as the main reinforcement material. Atom transfer radical polymerization (ATRP) was used to graft polyionic liquids (PILs) with different hydrophilic anions to the CNTs' surfaces. Solution casting and compressive melt molding were used to prepare the PVDF-composite piezoelectric films. Micro-capacitance formed by the PIL grafted CNTs dispersed well in the PVDF matrix, and their effects on the crystalline form and piezoelectric properties were studied. The hydrophobic hexafluorophosphate anion (-PF6-) can significantly improve the CNTs dispersion and enhance the micro-capacitance formation in the PVDF matrix. During solution crystallization, the synergistic effect of CNTs and PIL on the PVDF and the solvent effect made the content of beta phase of PVDF/CNTs@PIL-PF6 film rea ch 80.2%, resulting in a high dielectric constant of 188 and a piezoelectric coefficient of 36. In the process of melt crystallization, due to shear stretching and extrusion, the CNTs@PIL-PF6 had an obvious nucleation effect on the polar crystalline phase of PVDF, with a beta phase content up to 99.3%, leading to the higher dielectric constant of 530 and the piezoelectric coefficient of 31. The current discovery provides a development direction for smart piezoelectric polymer matrix composites, which have great potential in preparing piezoelectric energy storage materials.

All-polymer piezo-ionic-electric electronics - Tianpei Xu, Long Jin, Yong Ao, Jieling Zhang, Yue Sun, Shenglong Wang, Yuanxiao Qu, Longchao Huang (Nature Communications, 2024)
Abstract Piezoelectric electronics possess great potential in flexible sensing and energy harvesting applications. However, they suffer from low electromechanical performance in all-organic piezoelectric systems due to the disordered and weakly-polarized interfaces. Here, we demonstrated an all-polymer piezo-ionic-electric electronics with PVDF/Nafion/PVDF (polyvinylidene difluoride) sandwich structure and regularized ion-electron interfaces. The piezoelectric effect and piezoionic effect mutually couple based on such ion-electron interfaces, endowing this electronics with the unique piezo-ionic-electric working mechanism. Further, owing to the massive interfacial accumulation of ion and electron charges, the electronics obtains a remarkable force-electric coupling enhancement. Experiments show that the electronics presents a high d 33 of ~80.70 pC N −1 , a pressure sensitivity of 51.50 mV kPa −1 and a maximum peak power of 34.66 mW m −2 . It is applicable to be a transducer to light L EDs, and a sensor to detect weak physiological signals or mechanical vibration. This work shows the piezo-ionic-electric electronics as a paradigm of highly-optimized all-polymer piezo-generators.

High piezoelectric property with exceptional stability in self-poled ferroelectric films - Lisha Liu, Jiaojiao Yi, Kun Xu, Zhen Liu, Mingmeng Tang, Le Dai, Xuan Gao, Yang Liu (Nature Communications, 2024)
Ferroelectric films are highly sought-after in micro-electro-mechanical systems, particularly with the trend towards miniaturization. However, their tendency to depolarize and degradation in piezoelectric properties when exposed to packaging procedures at temperatures exceeding 260 °C remains a significant challenge. Here, we reveal the prerequisites for self-poling and leverage these insights to achieve unprecedented macroscopic performance through a two-step approach involving texture construction and hierarchical heterogeneity engineering. The significant [001] texture and fine Zr/Ti heterogeneity, facilitated by a PbO-TiO2 buffer, enable a piezoelectric charge coefficient of 550 pC/N in self-poled Pb(Zr0.52Ti0.48)O3 film. This material demonstrates impressive resilience to elevated temperatures up to 300 °C, experiencing less than a 16% degradation in performance. Our approach can be extended to other ferroelectric systems, offering an innovative solution for high-temperature packa ging and harsh environments in practical electro-mechanical applications. The authors realize a high piezoelectric charge coefficient in a self-poled ferroelectric film, addressing the persistent challenge of piezoelectric property degradation during industrial packaging and shaping the landscape of commercial ferroelectrics for micro-electro-mechanical systems.

High‐Performance Bimodal Temperature/Pressure Tactile Sensor Based on Lamellar CNT/MXene/Cellulose Nanofibers Aerogel with Enhanced Multifunctionality - Lin Tian, Fu‐Lin Gao, Yu‐Xiao Li, Zhi‐Yue Yang, Xinghe Xu, Zhong‐Zhen Yu, Jie Shang, Run‐Wei Li (Advanced Functional Materials, 2024)
Abstract The rapid development of thermoelectric‐piezoresistive dual‐mode sensors has opened new avenues for enhancing the functionality, miniaturization, and integration of flexible tactile sensors. However, existing research primarily focuses on decoupling temperature and pressure responses, which leaves a significant gap in optimizing sensor performance and exploring multifunctional applications. To address this limitation, a composite aerogel with a layered porous structure is developed, integrating carbon nanotubes and MXene as conductive materials and reinforced with cellulose nanofibers. The innovative design, characterized by ultra‐low thermal conductivity along with superior electrical and thermoelectric properties, allows the resulting sensor to monitor temperature and pressure stimuli without interference through thermoelectric and piezoresistive mechanisms. Demonstrated results reveal exceptional sensing capabilities, including a minimum detectable temperature variation of 0.03 K and a pressure detection limit of 0.3 Pa. The sensor exhibits high sensitivities of 33.5 µV K −1 and −45.2% kPa −1 , along with stability across both temperature and pressure stimuli. Furthermore, the unique multi‐modal sensing mechanism supports various applications, such as thermoelectric energy harvesting, material recognition, complex information transmission, smart wearable devices, electronic skin, and human‐computer interaction interfaces. This research presents a robust solution for designing high‐performance dual‐modal tactile sensors and significantly advances their practical applications across multiple domains.

Skin‐Inspired, Multifunctional, and 3D‐Printable Flexible Sensor Based on Triple‐Responsive Hydrogel for Signal Conversion in Skin Interface Electronics Health Management - Shuhuai Zheng, Lingyang Ruan, Fanmao Meng, Zhihong Wu, Yiyao Qi, Yukui Gao, Weizhong Yuan (Small, 2024)
Abstract Hydrogel‐based flexible electronic components have become the optimal solution to address the rigidity problem of traditional electronics in health management. In this study, a multipurpose hydrogel is introduced, which is formed by combining a dual‐network consisting of physical (chitosan, polyvinyl alcohol (PVA)) and chemical (poly(isopropyl acrylamide (NIPAM)‐ co ‐acrylamide (AM))) cross‐linking, along with signal conversion fillers (eutectic gallium indium (EGaIn), Ti 3 C 2 MXene, polyaniline (PANI)) for responding to external stimuli. Multiple sensing of dynamic and static signals is permissible for it. The strain sensor based on the hydrogel exhibits up to a 1000% resistance change within a 400% stretch range, and significant capacitance variations are observed upon touch. The temperature sensor yields a sensitivity of ≈−2.9% °C −1 at 20–40 °C and ≈65% °C −1 at 0–20 °C. The pH sensor responds with a sensitivity of near −13.68 mV pH −1 . A paper‐based triboelectric nanoge nerator can be assembled to collect action energy at 83 mW m −2 . The skin contact interface is kept in good condition owing to its 3D‐printability, controllable antibacterial properties, along high cell survival rate. This multifunctional hydrogel holds promise in facilitating the integration of diagnosis and maintenance.

Chemical‐Strain‐Engineered Adaptive Interfaces in Nanocomposite Films for Robust Ferroelectricity - Jiaqi Ding, Jie Tu, Hangren Li, Guoqiang Xi, Dongxing Zheng, Qingxiao Wang, Xixiang Zhang, Yuanyuan Hu (Advanced Functional Materials, 2024)
Abstract Strain is an effective means of tuning the crystal structure to obtain a variety of fascinating properties, but how to apply flexible strain to meet the different needs of the film at each location has rarely been reported. In this study, a novel approach for designing strain‐damping structures that facilitate the imposition of flexible strain is introduced. A wide range of strain modulation is demonstrated in SmCoO 3 films ( a ‐axis:+4.5%–+1.7%, b ‐axis: +3.2%–+0.4%, c ‐axis:+2.2%–+1.4%) under positive pressure by introducing Sm 2 O 3 as a dopant. When SmCoO 3 films are subjected to triaxial tensile strain, they exhibit a ferroelectric polarization of 7.12 µC cm −2 . Through positive pressure modulation, resulting in a further increase in the ferroelectric polarization (up to 11.62 µC cm −2 , which represents the maximum performance of the orthogonal rare earth transition metal oxide family). Moreover, the electron spin order can be effectively controlled, and the film's satu ration magnetization increases to 14.83 emu cm −3 (+94.1%). This damping structure allows for flexible modulation of chemical strain in epitaxial film, achieving a delicate balance between film strain and structure, which provides valuable insights for all ferroelectrics based on structural distortion.

High Tribo‐Charge Density Composite Nanofiber Membrane for Motion Sensing and Water Wave Energy Harvesting - Xue Zhao, Zhi Hao Zhao, Zhong Lin Wang, Guang Zhu, Jie Wang (Small, 2024)
Abstract Triboelectric nanogenerators (TENGs), among the most simple and efficient means to harvest mechanical energy, have great potential in renewable energy utilization. While the output performance of TENGs is still not high enough, which limits its practical application. Here, a poly(vinylidene fluoride) (PVDF)/fluorinated ethylene propylene nanoparticles (FEP NPs) porous nanofiber (PFPN) membrane with waterproof, breathable, surface superhydrophobic and high tribo‐negative properties is proposed for achieving high‐performance of TENGs. The PFPN‐based solid–solid contact PFPN‐TENG achieved an optimal electric output with a net tribo‐charge density of 294 µC m −2 , which is 42.2% more than that of polytetrafluoroethylene (PTFE) film. The PFNP membrane can maintain the best performance with almost no attenuation after 142680 working cycles. Based on its excellent triboelectric characteristics, the PFPN membrane shows its excellent performance for self‐powered body motion sensing and mechanical energy harvesting. A flexible solid–liquid contact PFPN‐TENG can achieve high electrical output with an average volume power density of ≈544.1 W m −3 by harvesting water wave energy. Such excellent performance of the PFPN membrane makes it a potential candidate to promote the power density of TENGs in harvesting blue water wave energy.

Ferroelectric elastomers of functionalized polar fillers in polydimethylsiloxane with improved dielectric and ferroelectric properties - Thulasinath Raman Venkatesan, Alessandra Hausmann, Jose Enrico Q. Quinsaat, A. Neels, Dorina M. Opris (Composites Part B Engineering, 2024)
Stretchable ferroelectric nanocomposites were prepared by combining the ferroelectric properties of vinylidene fluoride-based homopolymer (PVDF) and its copolymer based on trifluoroethylene (P(VDF-TrFE)) with the elasticity of polydimethylsiloxane (PDMS). To overcome the incompatibility of the polar filler with the non-polar matrix, functionalization of the filler nanoparticles was carried out. A detailed study of the composite films using optical, thermal, mechanical, and dielectric methods was made to find the impact of functionalization and to study the structure-property relationships in the 0-3 composites. Functionalization improved the mechanical properties as inferred from the reduced Mullins effect. It also increased the dielectric breakdown strength, which can allow higher poling fields ( E p ). From the scanning electron microscope images and mechanical tests on the composites with 20, 40, and 60 wt % of fillers, 40 wt % was found to be the optimum concentration and was chose n for further measurements. While a 40 wt % PVDF/PDMS composite at room temperature and E p = 5 V/μm showed a pyroelectric ( p ) coefficient of 0.06 μC/m 2 K, its 40 wt % copolymer counterpart for similar conditions showed a higher p (0.4 μC/m 2 K). However, the corresponding PVDF and P(VDF-TrFE) composites showed similar piezoelectric d 31 coefficients. This improved piezoelectric response of the PVDF composite is explained in terms of the additional contribution from Maxwell-Wagner interfacial polarization. A maximum d 31 co-efficient of 8.6 pC/N and 10.1 pC/N was measured for the 40 wt % homoand co-polymer polar composites, respectively, poled with E p = 20 V/μm and strained at 50% with a frequency of 0.1 Hz.

Piezoelectric‐Augmented Thermoelectric Ionogels for Self‐Powered Multimodal Medical Sensors - Ya‐Hsin Pai, Xu Chen, Run Zhu, Xinyi Ding, Shengqiang Bai, Ziqi Liang, Lidong Chen (Advanced Materials, 2024)
Abstract A paradigm ionogel consisting of ionic liquid (IL) and PVDF−HFP composites is made, which inherently possesses dual‐function ionic thermoelectric (iTE) and piezoelectric (PE) attributes. This study investigates an innovative “PE‐enhanced iTEs” effect, wherein the ionic thermopower exhibits a 58% enhancement while the ionic conductivity arises more than 2× within a PE‐induced internal electric field. By harnessing these multifaceted features, fully self‐powered, multimodal sensors demonstrate their superior energy conversion capabilities, which possessed minimum sensitivities of 0.13 mV kPa −1 and 0.96 mV K −1 in pressure and temperature alterations, respectively. The PE augmentation of iTEs is maximized by ≈3× under rising water pressure. Their swift and sophisticated responses to various in vivo vital signs simultaneously in a hemorrhagic shock scenario, indicative of good prospects in the clinical medicine field are showcased.

Bonding Optimization Strategies for Flexibly Preparing Multi‐Component Piezoelectric Crystals - Yuan Bai, Gang Tang, Lei Xie, He Lian, Shihao Wang, Chaopeng Liu, Qiao Yu, Jianying Ji (Advanced Materials, 2024)
Abstract Flexible films with optimal piezoelectric performance and water‐triggered dissolution behavior are fabricated using the co‐dissolution–evaporation method by mixing trimethylchloromethyl ammonium chloride (TMCM‐Cl), CdCl 2 , and polyethylene oxide (PEO, a water‐soluble polymer). The resultant TMCM trichlorocadmium (TMCM‐CdCl 3 ) crystal/PEO film exhibited the highest piezoelectric coefficient (d 33 ) compared to the films employing other polymers because PEO lacks electrophilic or nucleophilic side‐chain groups and therefore exhibits relatively weaker and fewer bonding interactions with the crystal components. Furthermore, upon slightly increasing the amount of one precursor of TMCM‐CdCl 3 during co‐dissolution, this component gained an advantage in the competition against PEO for bonding with the other precursor. This in turn improved the co‐crystallization yield of TMCM‐CdCl 3 and further enhanced d 33 to ≈71 pC/N, exceeding that of polyvinylidene fluoride (a commercial flexi ble piezoelectric) and most other molecular ferroelectric crystal‐based flexible films. This study presents an important innovation and progress in the methodology and theory for maintaining a high piezoelectric performance during the preparation of flexible multi‐component piezoelectric crystal films.

Flexible mechano-optical dual-responsive perovskite molecular ferroelectric composites for advanced anticounterfeiting and encryption - Shengshun Duan, Pinzhen Chen, Yu‐An Xiong, Fangzhi Zhao, Zheng‐Yin Jing, Guo‐Wei Du, Xiao Wei, Shengxin Xiang (Science Advances, 2024)
Hybrid organic-inorganic molecular ferroelectrics have emerged as promising materials for multifunctional piezoelectric devices. However, they present challenges in practical applications because of their inherent brittleness and poor ductility. Herein, we present a flexible mechano-optical dual-responsive molecular ferroelectric composite by incorporating trimethylchloromethyl ammonium (TMCM)–MnCl 3 into styrene ethylene butylene styrene (SEBS) matrix. The SEBS/TMCM-MnCl 3 exhibits excellent stretchable mechanical properties (tensile strain >1300%, thickness of 30 μm), piezoelectricity, and photoluminescence, enabling advanced visual-tactile–fused anticounterfeiting and encryption applications. Anticounterfeiting and antitampering tags are developed to judge whether the valued items are true or tampered with based on pattern recognition and piezoelectric response, respectively. Additionally, high-security password keyboards featuring triple-layer encryption are designed, offering m ore password combinations (524,288 times greater than those of traditional password devices relying solely on digital encryption) and enhanced security reliability against cracking attempts. This work can inspire designs of multifunctional optoelectronic materials and enable visual-tactile–fused intelligent applications in human-machine interfaces, information security, and advanced robotics.

Optimizing the Electrical Microenvironment Provided by 3D Micropillar Topography on a Piezoelectric BaTiO3 Substrate to Enhance Osseointegration - Xiaowen Sun, Yaru Guo, Xiaona Zheng, Yunyang Bai, Yi-Xuan Lü, Yang Xue, Ziming Cai, Erxiang Xu (Advanced Materials, 2024)
Abstract The electrical properties of bone implant scaffolds are a pivotal factor in regulating cellular behavior and promoting osteogenesis. The previous study shows that built‐in electric fields established between electropositive nanofilms and electronegative bone defect walls are beneficial for promoting bone defect healing. Considering that the physiological electrical microenvironment is spatially distributed in 3D, it is imperative to establish a 3D spatial charged microenvironment on bone scaffolds to optimize the efficacy of osseointegration. Nevertheless, this still poses a formidable challenge. Here, a bone repair strategy that utilizes micro‐scale 3D topography is developed on a piezoelectric BaTiO 3 (BTO) substrate to provide 3D spatial electrical stimulation. The BTO micropillar arrays, especially with a height of 50 µm and positive‐charge distribution (50 µm positive), promote the spreading, cytoskeletal reorganization, focal adhesion maturation, and osteogenic different iation of bone marrow mesenchymal stem cells (BMSCs). They enhanced the clustering of mechanosensing integrin α5 in BMSCs. The biomimetic 3D spatial electrical microenvironment accelerated bone repair and osseointegration in a rat femoral diaphysis defect repair model. The study thus reveals that implants with a 3D spatial electrical microenvironment can significantly enhance osseointegration, thereby providing a new strategy to optimize the performance of electroactive biomaterials for tissue regenerative therapies.

A Fully Integrated Orthodontic Aligner With Force Sensing Ability for Machine Learning‐Assisted Diagnosis - Hao Feng, Wenhao Song, Ruyi Li, Linxin Yang, Xiaoxuan Chen, Jiajun Guo, Xuan Liao, Lei Ni (Advanced Science, 2024)
Currently, the diagnosis of malocclusion is a highly demanding process involving complicated examinations of the dental occlusion, which increases the demand for innovative tools for occlusal data monitoring. Nevertheless, continuous wireless monitoring within the oral cavity is challenging due to limitations in sampling and device size. In this study, by embedding high-performance piezoelectric sensors into the occlusal surfaces using flexible printed circuits, a fully integrated, flexible, and self-contained transparent aligner is developed. This aligner exhibits excellent sensitivity for occlusal force detection, with a broad detection threshold and continuous pressure monitoring ability at eight distinct sites. Integrated with machine learning algorithm, this fully integrated aligner can also identify and track adverse oral habits that can cause/exacerbate malocclusion, such as lip biting, thumb sucking, and teeth grinding. This system achieved 95% accuracy in determining malocclus ion types by analyzing occlusal data from over 1400 malocclusion models. This fully-integrated sensing system, with wireless monitoring and machine learning processing, marks a significant advancement in the development of intraoral wearable sensors. Moreover, it can also facilitate remote orthodontic monitoring and evaluation, offering a new avenue for effective orthodontic care.

Biodegradable and Implantable Triboelectric Nanogenerator Improved by β‐Lactoglobulin Fibrils‐Assisted Flexible PVA Porous Film - Yichang Quan, Engui Wang, Han Ouyang, Lingling Xu, Lu Jiang, Lijing Teng, Jiaxuan Li, Lin Luo (Advanced Science, 2024)
Triboelectric nanogenerators (TENGs) are highly promising as implantable, degradable energy sources and self-powered sensors. However, the degradable triboelectric materials are often limited in terms of contact electrification and mechanical properties. Here, a bio-macromolecule-assisted toughening strategy for PVA aerogel-based triboelectric materials is proposed. By introducing β-lactoglobulin fibrils (BF) into the PVA aerogel network, the material's mechanical properties while preserving its swelling resistance is significantly enhanced. Compared to pure PVA porous film, the BF-PVA porous film exhibits an eightfold increase in fracture strength (from 1.92 to 15.48 J) and a fourfold increase in flexibility (from 10.956 to 39.36 MPa). Additionally, the electrical output of BF-PVA in triboelectric performance tests increased nearly fivefold (from 45 to 203 V). Leveraging these enhanced properties, a biodegradable TENG (bi-TENG) for implantable muscle activity sensing is developed, ach ieving real-time monitoring of neuromuscular processes. This innovation holds significant potential for advancing implantable medical devices and promoting new applications in bio-integrated electronics.

Flexible Piezoelectric Energy Harvesters with Mechanoluminescence for Mechanical Energy Harvesting and Stress Visualization Sensing - Xueting Fu, Yongquan Cao, Xinyue Song, Renbing Sun, Hai Jiang, Peng Du, Dengfeng Peng, Laihui Luo (Advanced Functional Materials, 2024)
Abstract Flexible piezoelectric energy harvesters (FPEHs) have wide applications in mechanical energy harvesting, portable device driving, and piezoelectric sensors. However, the poor output performance of piezoelectric energy harvesters and the intrinsic shortcoming of piezoelectric sensors that can only detect dynamic pressure limit their further applications. BaTiO 3 (BT) and PVDF are deposited on the glass fiber electronic cloth (GFEC) by impregnation and spin‐coating methods, respectively, to form BT‐GFEC/PVDF piezoelectric composite films. A mixed solution of mechanoluminescence (ML) particles ZnS:Cu and PDMS are used as the encapsulation layer to construct a high‐performance ML‐FPEH with self‐powered electrical and optical dual‐mode response characteristics. Due to the interconnection structure of the piezoelectric films, the prepared ML‐FPEH illustrates a high effective energy harvesting performance (≈58 V, ≈43.56 µW cm −2 ). It can also effectively harvest mechanical energy fr om human activities. More importantly, ML‐FPEH can sense stress distribution of hand‐writing via ML to achieve stress visualization, making up for the shortcomings of piezoelectric sensors. This work provides a new strategy for endowing FPEH with dual‐mode sensing and energy harvesting.

Breaking dielectric dilemma via polymer functionalized perovskite piezocomposite with large current density output - Asif Abdullah Khan, Avi Mathur, Lu Yin, Mahmoud N. Almadhoun, Jian Yin, Majid Haji Bagheri, Md Fahim Al Fattah, Araz Rajabi‐Abhari (Nature Communications, 2024)
Organometal halide perovskite (OHP) composites are flexible and easy to synthesize, making them ideal for ambient mechanical energy harvesting. Yet, the output current density from the piezoelectric nanogenerators (PENGs) remains orders of magnitude lower than their ceramic counterparts. In prior composites, high permittivity nanoparticles enhance the dielectric constant (ϵr) but reduce the dielectric strength (Eb). This guides our design: increase the dielectric constant by the high ϵr nanoparticle while enhancing the Eb by optimizing the perovskite structure. Therefore, we chemically functionalize the nanoparticles to suppress their electrically triggered ion migration for an improved piezoelectric response. The polystyrene functionalizes with FAPbBr2I enlarges the grains, homogenizes the halide ions, and maintains their structural integrity inside a polymer. Consequently, the PENG produces a current density of 2.6 µAcm−2N−1. The intercalated electrodes boost the current density to 2 5 µAcm−2N−1, an order of magnitude enhancement for OHP composites, and higher than ceramic composites. By functionalizing polystyrene with perovskite FAPbBr2I, both the dielectric constant and dielectric strength are controlled, leading to energy-dense composite films for piezoelectric nanogenerators with normalized current density of 25 µA.cm−2 N−1

Innovative Wearable Electronics: Next‐Generation Nitrogen‐Doped Lutetium‐Carbon Microspheres Composites for Robust Energy Harvesting - Nargish Parvin, Vineet Kumar, Sang‐Shin Park, Tapas Kumar Mandal, Sang Woo Joo (Small, 2024)
Abstract In the quest to advance wearable electronics, this study presents a novel method using nitrogen‐doped lutetium‐carbon microspheres (N, Lu‐CMS) for high‐performance piezoelectric energy harvesting. The synthesis of N, Lu‐CMS begins with the polymerization of sucrose, followed by the preparation of N, Lu‐CMS metal complexes through the incorporation of lutetium (III) nitrate hydrate and thiourea, yielding a black powder product. The wearable electronic device is designed with a silicon rubber (SR) matrix, reinforced with 0D fillers such as N, Lu‐CMS, or molybdenum disulfide (MoS₂). Mechanical testing revealed a significant improvement in compressive modulus, reaching 3.7 MPa (N, Lu‐CMS) at a concentration of 3 parts per hundred rubber (phr). Electromechanical assessments demonstrated efficient energy conversion, while biomechanical analysis, including thumb pressing tests, showed a notable increase in output voltage, peaking at ≈285 mV (N, Lu‐CMS) at 3 phr. This research provide s a foundation for future engineering applications, particularly in electronic packaging for wearable electronics and smart devices, underscoring the significant impact of N, Lu‐CMS in this emerging field. The surface power density achieved is 0.026 nW cm − 2 (N, Lu‐CMS) and 0.0056 nW cm − 2 (Hybrid). Lastly, the conversion efficiency is 6.26% for N, Lu‐CMS, and 1.05% for the hybrid system.

One-step high-speed thermal-electric aerosol printing of piezoelectric bio-organic films for wirelessly powering bioelectronics - Xuemu Li, Zhuomin Zhang, Yi Zheng, Junchen Liao, Zehua Peng, Pengyu Li, Xiaodan Yang, Xiaodong Yan (Science Advances, 2024)
Piezoelectric biomaterials hold a pivotal role in the progression of bioelectronics and biomedicine, owing to their remarkable electromechanical properties, biocompatibility, and bioresorbability. However, their technological potential is restrained by certain challenges, including precise manipulation of nanobiomolecules, controlling their growth across nano-to-macro hierarchy, and tuning desirable mechanical properties. We report a high-speed thermal-electric driven aerosol (TEA) printing method capable of fabricating piezoelectric biofilms in a singular step. Electrohydrodynamic aerosolizing and in situ electrical poling allow instantaneous tuning of the spatial organization of biomolecular inks. We demonstrate TEA printing of β-glycine/polyvinylpyrrolidone films, and such films exhibit the piezoelectric voltage coefficient of 190 × 10 −3 volt-meters per newton, surpassing that of industry-standard lead zirconate titanate by approximately 10-fold. Furthermore, these films demonstrat e nearly two orders of magnitude improvement in mechanical flexibility compared to glycine crystals. We also demonstrate the ultrasonic energy harvesters based on the biofilms, providing the possibility of wirelessly powering bioelectronics.

3D‐Printing of Highly Piezoelectric Barium Titanate Polymer Nanocomposites with Surface‐Modified Nanoparticles at Low Loadings - Mirko Maturi, Lorenzo Migliorini, Sara Villa, Tommaso Santaniello, Natalia Fernández‐Delgado, Sergio I. Molina, Paolo Milani, Alberto Sanz de León (Advanced Functional Materials, 2024)
Abstract This work describes the development and characterization of tetragonal barium titanate nanoparticles (BTO NPs) and their surface functionalization with dopamine dodecylamine (DDA), a lipophilic organic ligand. The so‐obtained lipophilic NPs (BTO‐DDA) are then formulated at low loadings (< 5 wt.%) into liquid photocurable resins for vat photopolymerization (VP) and 3D printed into solid objects. The printed composites are mechanically characterized in order to assess the effect of the nanomaterial on the mechanical properties of the 3D printed polymer, revealing no significant variations in the mechanical properties (tensile or flexural) of the nanocomposites compared to the original polymer matrix. In light of these results, the printed nanocomposites are studied in terms of their capacity to generate a separation of charge by the piezoelectric effect, typical of the BTO crystal structure. This study reveals that BTO‐loaded nanocomposites display outstanding piezoelectric c oefficients as high as 50 pC/N when BTO‐DDA is formulated at 3.0 wt.%, only slightly less than one‐third of the piezoelectric coefficient previously reported for bulk BTO, while preserving the mechanical properties of the polymer matrix.

Macroscopic Room-Temperature Magnetoelectricity in Piezoelectric (Core)–Ferrimagnetic (Shell) Nanocomposites - Junsok Choi, Ki Tae Nam, Eun‐Ho Sohn, Yongsok Seo (ACS Nano, 2024)
The magnetoelectric (ME) effect, which involves the interaction of magnetic and electric fields within a material, has a significant potential for various applications. Our study addresses the limitations of conventional magnetostriction-based ME materials by demonstrating an alternative approach that achieves substantial ME effects in core–shell-type nanocomposites at room temperature. By synthesizing ferrimagnetic Fe 3 O 4 nanoparticles onto piezoelectric poly(vinylidene fluoride) (PVDF) particles, we identified a distinct ME mechanism. In magnetorheological (MR) fluids, the magnetic-field-induced aggregation of Fe 3 O 4 nanoparticles, combined with the piezoelectricity of PVDF, leads to a pronounced ME effect, significantly enhancing the performance and stability of MR fluids. This research highlights a crucial observation of distinct ME effects, which could suggest potential pathways for advancements in practical applications including microfluidics, vibration dampers, tactile tech nologies, and biomedical and bioengineering fields.

Avian-inspired embodied perception in biohybrid flapping-wing robotics - Qian Li, Ting Tan, Benlong Wang, Zhimiao Yan (Nature Communications, 2024)
Avian feather intricate adaptable architecture to wing deformations has catalyzed interest in feathered flapping-wing aircraft with high maneuverability, agility, and stealth. Yet, to mimic avian integrated somatic sensation within stringent weight constraints, remains challenging. Here, we propose an avian-inspired embodied perception approach for biohybrid flapping-wing robots. Our feather-piezoelectric mechanoreceptor leverages feather-based vibration structures and flexible piezoelectric materials to refine and augment mechanoreception via coupled oscillator interactions and robust microstructure adhesion. Utilizing convolutional neural networks with the grey wolf optimizer, we develop tactile perception of airflow velocity and wing flapping frequency proprioception. This method also senses pitch angle via airflow direction and detects wing morphology through feather collisions. Our low-weight, accurate perception of flapping-wing robot flight states is validated by motion capture. This investigation constructs a biomechanically integrated embodied perception system in flapping-wing robots, which holds significant promise in reflex-based control of complex flight maneuvers and natural bird flight surveillance.

Ultrahigh thermal stability and piezoelectricity of lead-free KNN-based texture piezoceramics - Lihui Xu, Jinfeng Lin, Yuxuan Yang, Zhihao Zhao, Xiaoming Shi, Guanglong Ge, Jin Qian, Cheng Shi (Nature Communications, 2024)
The contradiction between high piezoelectricity and uniquely poor temperature stability generated by polymorphic phase boundary is a huge obstacle to high-performance (K, Na)NbO3 -based ceramics entering the application market as Pb-based substitutes. We possess the phase boundary by mimicking Pb(Zr, Ti)O3’s morphotropic phase boundary structure via the synergistic optimization of diffusion phase boundary and crystal orientation in 0.94(Na0.56K0.44)NbO3−0.03Bi0.5Na0.5ZrO3−0.03(Bi0.5K0.5)HfO3 textured ceramics. As a result, a prominent comprehensive performance is obtained, including giant d33 of 550 ± 30 pC/N and ultrahigh temperature stability (d33 change rate less than 1.2% within 25-150 °C), representing a significant breakthrough in lead-free piezoceramics, even surpassing the Pb-based piezoelectric ceramics. Within the same temperature range, the d33 change rate of the commercial Pb(Zr, Ti)O3−5 ceramics is only about 10%, and more importantly, its d33 (~ 350 pC/N) is much lower th an that of the (K, Na)NbO3-based ceramics in this work. This study demonstrates a strategy for constructing the phase boundary with MPB feature, settling the problem of temperature instability in (K, Na)NbO3-based ceramics. The authors induce a phase boundary similar to Pb(Zr, Ti)O3’s morphotropic phase boundary structure in (K, Na)NbO3-based ceramics, which exhibit high residual polarization as well as a significantly improved piezoelectric constant d33.

An elastic piezoelectric nanomembrane with double noise reduction for high-quality bandpass acoustics - Jialin Zhang, Yanjun Liu, Peiyi Wu (Nature Communications, 2024)
Polymer piezoelectrics with high electromechanical energy conversion (HEEC) are very promising for flexible acoustoelectric devices. However, reducing thickness and improving ordered polarization and ferroelectricity while maintaining high mechanical strength pose enormous fabrication challenges for polymer piezoelectric membranes—additionally, noise management in the acoustoelectric conversion remains an open issue. Here, we present a hydro-levitation superspreading approach for fabricating polymer nanomembranes with ordered crystalline phases and sub-nanostructures on the water surface. The elastic piezoelectric nanomembrane (EPN) is only 335 nanometers thick and consists of a conductance-stable piezoelectric layer sandwiched between two elastic damping layers. Such an all-in-one EPN can reduce background noise with low autocorrelation in the environment, suppress spurious noise caused by poor circuit contact, and achieve bandpass filtering of acoustic signals at human voice frequenc ies. This nanomembrane holds promise in repairing the auditory system of patients with tympanic membrane perforation and in a wide range of other acoustoelectric conversion fields. Creating flexible acoustoelectric devices with ultrathin thickness, high elasticity, stable conductivity, and high electromechanical energy conversion capability poses a challenge. Zhang et al. present a liquid crystal mediated technique that creates an elastic piezoelectric nanomembrane with double noise reduction, offering promise for auditory system reconstruction and other acoustoelectric conversion applications.

Self-healable and stretchable perovskite-elastomer gas-solid triboelectric nanogenerator for gesture recognition and gripper sensing - Feng Jiang, Gurunathan Thangavel, Jin Pyo Lee, A. Gupta, Yufei Zhang, Jian Yu, Tomoyuki Yokota, Kento Yamagishi (Science Advances, 2024)
Gas-solid triboelectric nanogenerators (GS-TENGs) based on porous elastomers provide a promising avenue for the design of self-powered sensors. However, the intrinsic limitation of low electric output in GS-TENGs could affect the accuracy and sensitivity of sensing systems. Here, we develop a porous composite by integrating an adhesive poly(siloxane-diphenylglyoxime-urethane) (PSDU) elastomer with ferroelectric (3,3-difluorocyclobutylammonium) 2 CuCl 4 [(DF-CBA) 2 CuCl 4 ] fillers. PSDU, an intrinsically triboelectric negative material with alternating hard-soft segments and supramolecular bonds, imparts excellent compressibility, adhesion, and self-healing properties to the composite. Simultaneously, the incorporation of (DF-CBA) 2 CuCl 4 as functional fillers leverages the formation of a hydrogen bonding network to enhance charge transfer processes. These fillers facilitate charge accumulation through an electric poling process, resulting in a power output improvement that surpasses 1400 times higher than that of a dense PSDU-based GS-TENG. Tapping onto the versatile properties of porous poly(siloxane-diphenylglyoxime-urethane)-perovskite (PSDU-PK) GS-TENGs, applications such as hand gesture/food recognition and dual-mode sensing system have been demonstrated, suggesting their promising potential in wearable electronics and smart agriculture.

Ultrahigh Capacitive Energy Storage in a Heterogeneous Nanolayered Composite - Xinhui Li, Xiaoxiao Chen, Jian Wang, Zhen Xin, Chun‐Yu Lei, Zhonghui Shen, Xin Zhang, Ce‐Wen Nan (Advanced Functional Materials, 2024)
Abstract Ferroelectric polymers with robust electrical polarization have been extensively investigated for capacitive energy storage. However, their inherent ferroelectric hysteresis loss limits the discharged energy density and compromises energy efficiency. Here, a heterogeneous nanolayered composite of ferroelectric polymer poly(vinylidene fluoride‐trifluoroethylene) (P(VDF‐TrFE)) and Al 2 O 3 is presented, which effectively mitigates ferroelectric hysteresis loss while maintaining high polarization and enhanced breakdown strength. Phase‐field simulations indicate that the polarization behaviors of the heterogeneous layered structure are jointly influenced by the thickness and dielectric constant of each component, which balances the electrical energy and Landau energy within the heterogeneous system. Guided by the theoretical simulations, optimized polarization behaviors are achieved with a significant reduction in remnant polarization and ferroelectric loss in the P(VDF‐TrFE)/Al 2 O 3 composites through careful control of P(VDF‐TrFE) thickness at nanometer scale. Moreover, the presence of multiple interfaces in the layered composites leads to a remarkable enhancement in polarization and breakdown strength. Consequently, an ultrahigh energy density of about 108 J cm −3 is achieved with a high charge–discharge efficiency of exceeding 80%. This work not only presents a straightforward approach to modify the polarization behaviors of ferroelectric polymers but also demonstrates a promising strategy for developing high‐energy‐density polymer nanocomposites.

Active-type piezoelectric smart textiles with antifouling performance for pathogenic control - Su Eon Lee, Hanna Lee, Jang Hwan Kim, Jae Chul Park, Sooah Kyung, Hayoung Choi, Su Hyun Baek, Jun Hyun Park (npj Flexible Electronics, 2024)
Abstract Recently, an investigation into preventive measures for coronavirus disease 2019 (COVID-19) has garnered considerable attention. Consequently, strategies for the proactive prevention of viral pathogens have also attracted significant interest in the field of wearable devices and electronic textiles research, particularly due to their potential applications in personal protective equipment. In this study, we introduce smart textiles designed with optimized piezoelectric devices that exhibit antifouling performance against microorganisms and actively inactivate viruses. These active-type smart textiles, which incorporate advanced lead zirconate titanate (PZT) ceramics, a stretchable interconnector array, and polymeric fabric, demonstrate effective antifouling capabilities, detaching approximately 90% of Escherichia coli and 75% of SARS-CoV-2. Furthermore, they inactivate viruses, releasing ~26.8 ng of N protein from ruptured SARS-CoV-2, using ultrasonic waves within the wearable platform. Experimental results show that piezoelectric smart textiles significantly reduce the spread of COVID-19 by leveraging the electrical and acoustic properties of PZT ceramics.

Porous flexible molecular-based piezoelectric composite achieves milliwatt output power density - Jia‐Qi Luo, Hai‐Feng Lu, Yijing Nie, Yuhang Zhou, Chang‐Feng Wang, Zhi‐Xu Zhang, Da‐Wei Fu, Yi Zhang (Nature Communications, 2024)
Molecular ferroelectrics have made breakthrough progress in intrinsic piezoelectric response that can be on par with advanced inorganic piezoelectric ceramics. However, their successful applications in high-density energy harvesting and self-powered flexible devices have been great challenge, owing to the low elastic moduli, intrinsically brittle, and fracture proneness of such material systems under mechanical loading. Here, we have developed a flexible porous composite piezoelectric material by using soft thermoplastic polyurethane (TPU) and molecular ferroelectric materials. Benefiting from the porous structure of TPU, the flexible piezoelectric composites enable effectively large doping ratio (50%) of [Me3NCH2Cl]CdCl3 (TMCM-CdCl3) and highly efficient stress absorption, coupled with the excellent piezoelectric properties of TMCM-CdCl3, to realize a superior power density (636.9 µW cm−2 or 1273.9 µW cm−3). This output is 2000 times higher than that of flexible piezoelectric material s represented by poly(vinylidene fluoride) (PVDF). We believe that the outstanding performance of the porous composite piezoelectric material would pave a feasible way for real industrial applications of molecular ferroelectrics. This work presents a flexible porous composite piezoelectric material combining thermoplastic polyurethane and TMCM-CdCl3, achieving near milliwatt power density, with promising industrial application prospects.

A Self‐Powered, Highly Sensitive, and Frequency‐Tunable Triboelectric Acoustic Sensor Inspired by the Human Cochlea - Donghee Kang, Hyejin Lee, Minseop Song, Yun Goo Ro, Min Sub Kwak, Jin‐Young Kim, Jinyoung Kim, Geonyoung Jung (Advanced Functional Materials, 2024)
Abstract Conventional acoustic sensors used in human–machine interfaces often face challenges such as power supply requirements, limited sensitivity, and inability to tune their frequency response. A self‐powered, highly sensitive, and frequency‐tunable triboelectric acoustic sensor inspired by the human cochlea is introduced. By mimicking hair cells in the organ of Corti, a tapered microhair‐structured ferroelectric poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) and barium titanate nanoparticle (BTNP) composite film is proposed, which demonstrates a 16‐fold increase in triboelectric output voltage (1.3 V) compared to a planar one at 2.8 Pa. Furthermore, inspired by the frequency selectivity of the basilar membrane with gradient structural variations, integrating a mass‐beam diaphragm is proposed with varying kirigami length and circular mass diameter that enables precise tuning of the resonance frequency of the sensor, resulting in a 32 times improvement in sensitivity (8 60 mV Pa −1 ) compared to a nonbiomimetic sensor (28 mV Pa −1 ) and an expanded dynamic range. The proposed sensor differentiates between human voices with different frequencies. A robotic hand integrated with the sensor responds to acoustic stimuli with programmed hand gestures, which highlights its potential in acoustic human–machine interfaces. The biomimetic approach to developing a self‐powered, highly sensitive, and frequency‐tunable acoustic sensor offers new possibilities for intuitive and immersive human–machine interfaces.

Triboelectric Nanogenerators Based on Transition Metal Carbo‐Chalcogenide (Nb2S2C and Ta2S2C) for Energy Harvesting and Self‐Powered Sensing - Yana Xiao, Zihua Li, Di Tan, Gachot Carsten, Bingang Xu (Advanced Science, 2024)
Abstract With burgeoning considerations over energy issues and carbon emissions, energy harvesting devices such as triboelectric nanogenerators (TENGs) are developed to provide renewable and sustainable power. Enhancing electric output and other properties of TENGs during operation is the focus of research. Herein, two species (Nb 2 S 2 C and Ta 2 S 2 C) of a new family of 2D materials, Transition Metal Carbo‐Chalcogenides (TMCCs), are first employed to develop TENGs with doping into Polydimethylsiloxane (PDMS). Compared with control samples, these two TMCC‐based TENGs exhibit higher electric properties owing to the enhanced permittivity of PDMS composite, and the best performance is achieved at a concentration of 3 wt. ‰ with open circuit voltage (Voc) of 112 V, short circuit current (Isc) of 8.6 µA and charge transfer (Qsc) of 175 nC for Nb 2 S 2 C based TENG, and Voc of 127 V, Isc of 9.6 µA, and Qsc of 230 nC for Ta 2 S 2 C based TENGs. These two TENGs show a maximum power density o f 1360 and 911 mW m −2 respectively. Moreover, the tribology performance is also evaluated with the same materials, revealing that the Ta 2 S 2 C/PDMS composite as the electronegative material presented a lower coefficient of friction (COF) than the Nb 2 S 2 C/PDMS composite. Their applications for energy harvesting and self‐powered sensing are also demonstrated.

Rational Modeling and Design of Piezoelectric Biomolecular Thin Films toward Enhanced Energy Harvesting and Sensing - Liwei Dong, Yun Ke, Yifan Liao, Jingyu Wang, Mingyuan Gao, Yaowen Yang, Jun Li, Fan Yang (Advanced Functional Materials, 2024)
Abstract The dynamic electromechanical coupling behavior of composite materials is highly dependent on external excitation frequency. While degradable biomolecular materials typically exhibit lower piezoelectric coefficients compared to ceramics, neglecting their frequency‐dependent performance in the design of piezoelectric devices further leads to less efficient utilization of their piezoelectric properties. This oversight greatly hinders the practical application of these materials. To address this, a novel fractional derivation (FD) theory‐assisted model is introduced to reversely design the glycine‐polyvinyl alcohol (PVA) thin films for versatile enhanced bio‐applications. An electromechanical coupling model incorporating FD theory is developed to learn the relationships between FD parameters, film dimensions, and dynamic electromechanical properties. This model accurately predicts the electromechanical performance of the films across a wide frequency range, validated by both fini te element simulations and experimental results. This therefore allows to establish key design principles for piezoelectric thin film in bioenergy harvesting and sensing, by tailoring thin film parameters to enhance the piezoelectric performance at specific stimuli frequencies. Demonstrations of glycine‐PVA film devices guided by this model reveal excellent performance in ultrasonic energy harvesting and carotid artery bio‐signal sensing. This study provides a robust theoretical framework for designing and optimizing biodegradable piezoelectric materials for various practical applications.

Room Temperature Single‐Component Organic Multiferroics with Large Magnetoelectric Coupling: Proficient Approach for Stray‐Magnetic Field Harvesting - Deepak Deepak, Dalip Saini, Sudip Kumar Naskar, Dipankar Mandal, Raj Kumar Roy (Small, 2024)
Abstract Magnetoelectric materials are highly desirable for technological applications due to their ability to produce electricity under a magnetic field. Among the various types of magnetoelectric materials studied, their organic counterparts provide an opportunity to develop solution‐processable, flexible, lightweight, and wearable electronic devices. However, there is a rare choice of solution‐processable, flexible, lightweight magnetoelectric materials which has tremendous technological interest. A supramolecular scaffold with precisely positioned structure‐forming and functional units (electrical dipoles and magnetic spins) is designed so that self‐assembly results in functional unit organization. Structure‐forming segments allow these scaffolds to self‐assemble into hierarchically ordered structures in nonpolar solvents, creating nanofibrous organogel networks. In particular, the xerogel derived from this organogel exhibits the highest magnetoelectric coupling coefficient (α ME ≈ 216 mV Oe −1 cm −1 ) reported to date for organic materials. This is even greater than commonly envisioned composite materials made of piezoelectric polymers and inorganic magnets. This single‐component organic multiferroic material displays ferroelectricity ( T c ≈ 46 °C) and paramagnetic behavior at room temperature. With this, it is demonstrated that the possibilities of effectively harvesting stray magnetic fields that are copiously available in the surroundings and wasted otherwise.

Recent Advances in Wearable Electromechanical Sensors Based on Auxetic Textiles - Milad Razbin, Roohollah Bagherzadeh, Mohsen Asadnia, Shuying Wu (Advanced Functional Materials, 2024)
Abstract Textile‐based electromechanical sensors are increasingly used as wearable sensors for various applications, such as health monitoring and human‐machine interfaces. These sensors are becoming increasingly popular as they offer a comfortable and conformable sensing platform and possess properties that can be tuned by selecting different fiber materials, yarn‐spinning techniques, or fabric fabrication methods. Although it is still in its early stages, recent attempts have been made to introduce auxeticity to textile sensors to enhance their sensitivity. Having a negative Poisson's ratio, i.e., undergoing expansion laterally when subjected to tensile forces and contraction laterally under compressive forces, makes them distinct from conventional sensors with positive Poisson's ratio. This unique feature has demonstrated great potential in enhancing the performance of electromechanical sensors. This review presents an overview of electromechanical sensors based on auxetic textiles (textiles made from auxetic materials and/or non‐auxetic materials but with auxetic structures), specifically focusing on how the unique auxetic deformation impacts sensing performance. Sensors based on different working mechanisms, including piezoelectric, triboelectric, piezoresistive, and piezocapacitive, are covered. It is envisioned that incorporating auxeticity and electromechanical sensing capabilities into textiles will significantly advance wearable technology, leading to new sensors for health monitoring, fitness tracking, and smart clothing.

Hydrogel‐Based Functional Materials for Thermoelectric Applications: Progress and Perspectives - Chenyang Zhang, Xiao‐Lei Shi, Qingyi Liu, Zhi‐Gang Chen (Advanced Functional Materials, 2024)
Abstract Hydrogels are renowned for their complex structures and unique physicochemical properties, establishing them as key materials in bioenergy harvesting applications. They are used in various applications, including triboelectric nanogenerators, piezoelectric, hydraulic, thermoelectric, and biofuel cells. Among these, hydrogels as key materials for thermoelectric applications represent a technology capable of continuously converting biological energy (thermal energy) into electrical energy. This technology shows great potential and commercial value in body monitoring, energy storage, and human‐machine interaction applications. Given its rapid development, a timely review focusing on the research progress of hydrogels and their composites in thermoelectric technology is presented. This review discusses various types of hydrogels used for thermoelectric power generation and refrigeration, their unique properties, strategies for enhancing their thermoelectric performance, and their applications in the field. Finally, the remaining challenges and feasible strategies are identified for improving the efficiency, stability, application range, and system‐level integration of next‐generation hydrogels for thermoelectric applications.

Efficient Permeable Monolithic Hybrid Tribo‐Piezo‐Electromagnetic Nanogenerator Based on Topological‐Insulator‐Composite - Beibei Shao, Tzu‐Ching Lu, Ming‐Han Lu, Yi‐Ting Chen, Tai‐Chen Wu, Wei‐Chen Peng, Tien‐Yu Ko, Jiann‐Yeu Chen (Advanced Materials, 2024)
Abstract Escalating energy demands of self‐independent on‐skin/wearable electronics impose challenges on corresponding power sources to offer greater power density, permeability, and stretchability. Here, a high‐efficient breathable and stretchable monolithic hybrid triboelectric‐piezoelectric‐electromagnetic nanogenerator‐based electronic skin (TPEG‐skin) is reported via sandwiching a liquid metal mesh with two‐layer topological insulator‐piezoelectric polymer composite nanofibers. TPEG‐skin concurrently extracts biomechanical energy (from body motions) and electromagnetic radiations (from adjacent appliances), operating as epidermal power sources and whole‐body self‐powered sensors. Topological insulators with conductive surface states supply notably enhanced triboelectric and piezoelectric effects, endowing TPEG‐skin with a 288 V output voltage (10 N, 4 Hz), ∼3 times that of state‐of‐the‐art devices. Liquid metal meshes serve as breathable electrodes and extract ambient electromagne tic pollution (±60 V, ±1.6 µA cm −2 ). TPEG‐skin implements self‐powered physiological and body motion monitoring and system‐level human‐machine interactions. This study provides compatible energy strategies for on‐skin/wearable electronics with high power density, monolithic device integration, and multifunctionality.

Multifunctional Thermochromic Dye‐Integrated Hybrid Nanogenerators for Mechanical Energy Harvesting and Real‐Time IoT Sensing - Sontyana Adonijah Graham, Punnarao Manchi, Mandar Vasant Paranjape, Anand Kurakula, Venkata Siva Kavarthapu, Jun Kyu Lee, Jae Su Yu (Advanced Functional Materials, 2024)
Abstract Hybrid nanogenerators are advanced mechanical energy harvesters capable of simultaneously scavenging multiple types of energy. Additionally, thermochromic materials provide a practical and visually assessable method for real‐time temperature monitoring. In this report, a novel energy harvester and sensing patch (EHSP) is introduced, that utilizes combined piezoelectric and triboelectric effects to harvest mechanical energy efficiently. To optimize the EHSP, various energy harvester configurations are fabricated and tested, and the dielectric properties of triboelectric films are systematically investigated. These improvements are implemented to augment the overall energy harvesting capability. The thermochromic properties of the EHSP are also explored to enhance both the electrical performance and thermal responsiveness. The EHSP demonstrates the ability to generate maximum voltage and current outputs of 350 V and 20.4 µA, respectively. Moreover, it can detect temperature chan ges within seconds, making it suitable for both energy harvesting and sensing applications. The EHSP is tested in practical scenarios, proving its efficiency as an energy harvester and sensor for everyday human activities. Furthermore, its integration with multiple hybrid nanogenerators showcases its potential for industrial and wearable sensing applications.

Integrated Piezoelectric/Pyroelectric Sensing from Organic–Inorganic Perovskite Nanocomposites - Bin Chai, Kunming Shi, Yalin Wang, Yijie Liu, Fei Liu, Lei Zhu, Xingyi Huang (ACS Nano, 2024)
Flexible ferroelectric materials are in high demand in emerging energy harvesting and self-powered sensing electronics. However, current flexible ferroelectric polymers, such as poly(vinylidene fluoride) (PVDF) and P(VDF-co-trifluoroethylene) [P(VDF-TrFE)], cannot fulfill the requirement of emerging applications because of their low piezoelectric/pyroelectric performance. In this work, using organic–inorganic hybrid perovskite [(4-aminotetrahydropyran)2PbBr2Cl2] ferroelectric nanorods as reinforcement and P(VDF-TrFE) as the matrix, we prepared flexible core–sheath piezoelectric nanofibers and pyroelectric nanocomposite films. The core–sheath nanofibers possess a record-high piezoelectric coefficient of 78.1 pC·N–1, and the output voltage reaches to 192 V, with the maximum power density of 1.04 W·m–2. On the other hand, the nanocomposite film exhibits a high pyroelectric coefficient of 58.2 μC·m–2·K–1 at 333 K, which yields a voltage of 6.1 V under 6.6 K temperature fluctuation. An inte grated flexible sensing device was prepared by combining piezoelectric nanofibers and pyroelectric films, which can wirelessly detect vibration and temperature fluctuation simultaneously. The integrated device is suitable for pipelines, power equipment, and other scenarios, where vibration and temperature need to be monitored at the same time.

Advancing Charge Density in Temperature‐Dependent Amphiphile Metal–Organic Polyhedra‐Based Triboelectric Nanogenerators - Swathi Ippili, Gobbilla Sai Kumar, Arti Sharma, Yoonah Ko, Seungbum Hong, Mahendra Goddati, Haneesh Saini, Jaebeom Lee (Advanced Energy Materials, 2024)
Abstract In this study, a mechanically flexible structure, a cuboctahedral metal‐organic polyhedra (MOP) Cu 24 [5‐(octyloxy) isophthalic acid] 24 Cu (II) paddlewheel clusters coordinated with (5‐(octyloxy) isophthalate), resulting in significantly enhanced hydrolytic stability are prepared. It should be noted that CuMOP‐1 exhibits evenly and symmetrically distributed non‐polar long alkyl chains and polar hydroxy groups, facilitating self‐assembly into higher‐order structures reminiscent of amphiphiles. Furthermore, the resultant CuMOP‐1 undergoes a phase change at 150–160 °C as confirmed temperature‐dependent Raman spectroscopy (RS), thermogravimetric analysis and Differential Scanning Calorimetry (TGA‐DSC). The possible use of Cu‐MOP‐1 for capturing mechanical energy is demonstrated by creating a flexible hybrid piezoelectric‐triboelectric nanogenerator (HP‐TENG). The resultant CuMOP‐1@ Polyvinylidene fluoride(PVDF) membrane‐based HP‐TENG demonstrates enhanced triboelectric output vol tage of 547.5 V, current density of 15.16 µAcm −2 , and power density of 2.8 mWcm −2 due to its increased surface charge density and a substantial rise in the dielectric constant. Furthermore, the amphiphiles and phase change in CuMOP‐1 lead to ∽73% increase in voltage and 60% in current density of HP‐TENG in high‐temperature (140 °C) environments. HP‐TENG also exhibits exceptional temperature‐ and pressure‐sensing abilities, with sensitivities of 1.81 V°C −1 and 7.12 V°kPa −1 , respectively, showcasing its feasibility over a wide range of temperatures and pressures.

Investigating superior performance by configuring bimetallic electrodes on fabric triboelectric nanogenerators (F-TENGs) for IoT enabled touch sensor applications - Akshaya Kumar Aliyana, Satyaranjan Bairagi, Charchit Kumar, Daniel M. Mulvihill, George K. Stylios (Nano Energy, 2024)
Fabric Triboelectric Nanogenerators (F-TENGs) are increasingly becoming more significant in wearable monitoring and beyond. These devices offer autonomous energy generation and sensing capabilities, by replacing conventional batteries in flexible wearables. Despite the substantial effort, however, achieving high output with optimal stability, durability, comfort, and washability poses substantial challenges, so we have yet to see any practical commercial uses of these materials. This study focuses on output and investigates the impacts of mono and bimetallic composite fabric electrode configurations on the output performance of F-TENGs.

Integration of ZnS: Mn2⁺ Microparticles into Electrospun PVDF‐Based Nanofibers for Enhanced Mechanoluminescence - Zhongxiang Wang, Youyi Tai, Zuyang Ye, Jin Nam, Yadong Yin (Advanced Functional Materials, 2024)
Abstract Incorporating mechanoluminescent (ML) materials into piezoelectric polymer nanofibers enables the development of advanced pressure sensors and human–machine interactive devices by providing mechanical flexibility and enhancing processibility. This study demonstrates that introducing water during the electrospinning process significantly improves the piezoelectric properties of polyvinylidene fluoride (PVDF)‐based polymers, attributed to the enhanced formation of piezoelectrically active β ‐phases. A biphasic relationship between piezoelectricity and water concentration is revealed, with an optimal water concentration of 4 wt.% for both polyvinylidene fluoride‐hexafluoropropylene (PVDF‐HFP) and polyvinylidene fluoride‐trifluoroethylene (PVDF‐TrFE). Furthermore, the inclusion of water in the electrospinning solution facilitates the integration of ZnS: Mn 2+ mechanoluminescent microparticles into the polymer fibers, resulting in fibrous composite membranes with significantly enha nced mechano‐optical responses. After thermal annealing, the fibrous membrane by electrospinning PVDF‐TrFE and ZnS: Mn 2+ microparticles with 8 wt.% water addition demonstrates the best ML performance with high light emission intensity and reduced pressure threshold down to 18 kPa. This exceptional performance can be attributed to the local electric field generated by the encapsulation of microparticles within the PVDF‐TrFE fibers, which facilitates electroluminescence and subsequently boosts the overall light emission.

Large Enhancement on Performance of Flexible Cellulose‐Based Piezoelectric Composite Film by Welding CNF and MXene via Growing ZnO to Construct a “Brick‐Rebar‐Mortar” Structure - Qingtao Zhu, Xianfen Chen, Duoduo Li, Lei Xiao, Junyan Chen, Li-Jun Zhou, Jiabin Chen, Quanping Yuan (Advanced Functional Materials, 2024)
Abstract Cellulose‐based piezoelectric composites have attracted extensive attention in recent years due to their low cost, easy molding, high flexibility, and biocompatibility in the manufacture of piezoelectric nanogenerators (PENG) and sensors. In this work, cellulose nanofibril (CNF)/MXene@ZnO (CM@ZnO) piezoelectric composite films with “brick‐rebar‐mortar” structure are prepared by growing ZnO on the mixed substrate via a high‐efficiency two‐step hydrothermal method. As a hard bridge, ZnO welds CNF and MXene together to construct the “brick‐rebar‐mortar” structure, which greatly improves the piezoelectric performance. Its tensile strength reaches 65.13 ± 3.61 MPa, as well as that the longitudinal piezoelectric constant ( d 33 ) attains 14.3 ± 1.3 pC N −1 . Under the force of 300 KPa, the open‐circuit voltage ( V OC ) and short‐circuit current ( I SC ) of CM@ZnO PENG are as high as 17.15 V and 997 nA, respectively. Under the force of 100 KPa, it can charge a 1.0 µF commercial capac itor to 6.07 V in 400 s. The assembled flexible piezoelectric sensor can accurately collect the pressure or vibration signal caused by bending the wrist (0.59 V) with excellent sensitivity. The performance demonstrates the feasibility of its application in wearable smart devices and provides a reference for new cellulose‐based PENGs.

Electronic cooling and energy harvesting using ferroelectric polymer composites - Kailun Zou, Peijia Bai, Kanghua Li, Fangyuan Luo, Jiajie Liang, Lei Lin, Rujun Ma, Qi Li (Nature Communications, 2024)
Thermal management emerges as a grand challenge of next-generation electronics. Efforts to develop compact, solid-state cooling devices have led to the exploration of the electrocaloric effect of ferroelectric polymers. Despite recent advances, the applications of electrocaloric polymers on electronics operating at elevated temperatures remain essentially unexplored. Here, we report that the ferroelectric polymer composite composed of highly-polarized barium strontium titanate nanofibers and electron-accepting [6,6] phenyl-C61-butyric acid methyl ester retains fast electrocaloric responses and stable cyclability at elevated temperatures. We demonstrate the effectiveness of electrocaloric cooling in a polymer composite for a pyroelectric energy harvesting device. The device utilizes a simulated central processing unit (CPU) as the heat source. Our results show that the device remains operational even when the CPU is overheated. Furthermore, we show that the composite functions simultane ously as a pyroelectric energy converter to harvest thermal energy from an overheated chip into electricity in the electrocaloric process. This work suggests a distinct approach for overheating protection and recycling waste heat of microelectronics. Application of elascocaloric materials for compact cooling devices at elevated temperature is challenging. This study introduces a ferroelectric polymer which shows rapid electrocaloric and pyroelectric responses under high temperature. An energy harvester is demonstrated to work normally even with an overheated CPU.

Engineering Heterostructured Piezoelectric Nanorods with Rich Oxygen Vacancy‐Mediated Piezoelectricity for Ultrasound‐Triggered Piezocatalytic Cancer Therapy - Wen‐Ying Chen, Qi Chen, Feifei Song, Mengying Hua, Meiqi Chang, Wei Feng, Li Ding, Bin Yang (Advanced Functional Materials, 2024)
Abstract Using piezoelectric bionanomaterials to promote the generation of reactive oxygen species (ROS) is being increasingly recognized in ultrasound (US)‐triggered tumor treatments. The mechanism underlying this innovative treatment involves US irradiation, which activates the built‐in electric field (BIEF) and induces energy‐band bending in piezoelectric materials (PEMs). In this study, Sr 0.5 Ba 0.5 Nb 2 O 6 (SBN) nanorods (NRs) are synthesized using a molten salt method. Subsequently, oxygen‐vacancy (OV)‐rich SBN/Sr 2 Nb 2 O 7 (SBN/SNO) heterojunction nanocomposites (NCs) are fabricated via H 2 annealing of the SBN NRs. The engineering strategy focused on enhancing ROS generation, thereby augmenting the piezoelectric catalytic activity of the NCs. This configuration ensures that the BIEF and heterojunction‐induced field act synergistically to provide a sustained driving force for the separation of electron‐hole (e − ‐h + ) pairs. Importantly, the OVs on the surfaces of the H 2 ‐a nnealed SBN NRs create electron‐rich sites, which substantially enhance their piezocatalytic capabilities. In vitro and in vivo analyses of hepatocellular carcinoma (HCC) models demonstrate the significant cytotoxic and tumor‐inhibitory capabilities of this rich OV‐mediated sonopiezoelectric therapy (SPT) and illustrate its potential as a promising therapeutic approach against cancer.

First principles insights into triboelectrification during solid-solid contact: The curious case of 2D MXenes and aluminum - Ghulam Abbas, Syed Muhammad Alay-e-Abbas, J. Andreas Larsson, Yijun Shi (Nano Energy, 2024)
Recently, triboelectric nanogenerators (TENGs) have been widely used for energy harvesting and self-powered sensing due to their significant and unique advantages. However, the intrinsic mechanisms that contribute to tribo-electricification (TE) between two materials remain as a subject of rigorous debate. In addition to predicting the qualitative charge transfer in solid-solid contacts based on the difference in the work functions of the two moieties constituting the interface, we argue that it is essential to obtain atomic-level, first principles, insights into the bonding properties, quantitative charge transfer, and the possible presence of a electrostatic potential barrier at the interface to fully understand the TE mechanism of a system. We have utilized dispersion-corrected density functional theory (DFT) calculations in this study to systematically investigate the TE potential of bare surface Ti3C2 and Ti3N2 2D MXene monolayers and their surface functionalized modifications Ti3 C2R2 and Ti3N2R2 (where R = -O, -OH, or -F) in contact with Al(111). For these heterostructures, we have analyzed the adhesive energy of the interfaces, the nature of interaction through the electron localization function (ELF), and the charge distribution, which have revealed distinct characteristics of MXene/Al contacts for these monolayer/metal interfaces at their equilibrium distance and the changes in their properties under uniaxial pressure. Among all the metallic 2D MXene variants investigated in this study, we have determined that Ti3C2F2/Al and Ti3N2F2/Al interfaces show exceptional potential for TE.

Stretching Aligned Hydrogen Bonding Network to Evoke Mechanically Robust and High‐Energy‐Density P(VDF‐HFP) Dielectric Film Capacitors - Qi Wu, Xingang Liu, Yuanbo Liu, Chuhong Zhang, Min Nie (Small, 2024)
Abstract Polymer‐based dielectric film capacitors are essential energy storage components in electronic and power systems due to their ultrahigh power density and ultra‐fast charge storage/release capability. Nonetheless, their relatively low energy density does not fully meet the requirements of power electronics and pulsed power systems. Herein, a scalable composite dielectric film based on a ferroelectric polymer with edge hydroxylated boron nitride nanosheets (BNNS‐OH) is fabricated via the construction of a hydrogen bonding network and stretching orientation strategy. The presence of hydroxyl groups on boron nitride aids in forming a robust hydrogen bonding network within the ferroelectric polymer, leading to a significant increase in Young's modulus and superior dielectric performance. Furthermore, the stretching process aligns the BNNS‐OH and the hydrogen bonding network along the drawing direction via covalent and hydrogen bonding interaction, resulting in a remarkable tensile strength (109 MPa), breakdown strength (688 MV m −1 ), and energy density (28.2 J cm −3 ), outperforming mostrepresentative polymer‐based dielectric films. In combining the advantages of a simple preparation process, extraordinary energy storage performance, and low‐cost raw materials, this strategy is viable for large‐scale production of polymer‐based dielectric films with high mechanical and dielectric performance and opens a new path for the development of next‐generation energy storage applications.

Ultrastable piezoelectric biomaterial nanofibers and fabrics as an implantable and conformal electromechanical sensor patch - Tong Li, Yongjiu Yuan, Long Gu, Jun Li, Yan Shao, Shancheng Yan, Yunhe Zhao, Corey Carlos (Science Advances, 2024)
Poly(l-lactic acid) (PLLA) is a widely used U.S. Food and Drug Administration-approved implantable biomaterial that also possesses strong piezoelectricity. However, the intrinsically low stability of its high-energy piezoelectric β phase and random domain orientations associated with current synthesis approaches remain a critical roadblock to practical applications. Here, we report an interfacial anchoring strategy for fabricating core/shell PLLA/glycine (Gly) nanofibers (NFs) by electrospinning, which show a high ratio of piezoelectric β phase and excellent orientation alignment. The self-assembled core/shell structure offers strong intermolecular interactions between the -OH groups on Gly and C=O groups on PLLA, which promotes the crystallization of oriented PLLA polymer chains and stabilizes the β phase structure. As-received core/shell NFs exhibit substantially enhanced piezoelectric performance and excellent stability. An all NF-based nonwoven fabric is fabricated and assembled as a flexible nanogenerator. The device offers excellent conformality to heavily wrinkled surfaces and thus can precisely detect complex physiological motions often found from biological organs.

All‐Organic Piezo‐Photocatalytic Film with Highly Efficient Catalysis, Weak‐Force Excitation, and Recyclability - Ya Liu, Wangshu Tong, Jialin Zhuang, Yihe Zhang (Small, 2024)
Polyaniline (PANI), a typical organic photocatalyst, has an adjustable structure and good stability, can be easily synthesized on a large scale, and is economical. PANI is doped with ions to regulate its internal structure and improve its photocatalytic performance. However, its photocatalytic performance is limited by the doping concentration and its intrinsic properties, hindering its further application. Herein, PANI films with a piezo-photocatalytic function are fabricated to improve photocatalytic performance and explore their self-powered environmental purification property. PANI/poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) sandwich films, with PVDF-HFP as the interlayer, are prepared by introducing a piezoelectric field into PANI photocatalysts, thereby achieving excellent piezo-photocatalytic performance. The as-fabricated piezo-photocatalyst degrades methyl orange at a rate of 91.2% after 60 min under magnetic stirring. Owing to the low Young's modulus of the al l-organic catalyst, self-powered purification is realized using the PANI/PVDF-HFP film. Leaf surfaces are functionalized by loading the film in them for removing pollutants under sunlight and water flow. Thus, this study proposes a common strategy, wherein a piezoelectric interlayer is introduced to load the organic photocatalyst for preparing an all-organic piezo-photocatalyst. This piezo-photocatalyst can be easily recycled and responds to weak forces, realizing its application for self-powered environmental purification.

Contact-electro-catalytic CO2 reduction from ambient air - Nannan Wang, Wenbin Jiang, Jing Yang, Haisong Feng, Youbin Zheng, Sheng Wang, Bofan Li, Jerry Zhi Xiong Heng (Nature Communications, 2024)
Abstract Traditional catalytic techniques often encounter obstacles in the search for sustainable solutions for converting CO 2 into value-added products because of their high energy consumption and expensive catalysts. Here, we introduce a contact-electro-catalysis approach for CO 2 reduction reaction, achieving a CO Faradaic efficiency of 96.24%. The contact-electro-catalysis is driven by a triboelectric nanogenerator consisting of electrospun polyvinylidene fluoride loaded with single Cu atoms-anchored polymeric carbon nitride (Cu-PCN) catalysts and quaternized cellulose nanofibers (CNF). Mechanistic investigation reveals that the single Cu atoms on Cu-PCN can effectively enrich electrons during contact electrification, facilitating electron transfer upon their contact with CO 2 adsorbed on quaternized CNF. Furthermore, the strong adsorption of CO 2 on quaternized CNF allows efficient CO 2 capture at low concentrations, thus enabling the CO 2 reduction reaction in the ambient air. C ompared to the state-of-the-art air-based CO 2 reduction technologies, contact-electro-catalysis achieves a superior CO yield of 33 μmol g −1 h −1 . This technique provides a solution for reducing airborne CO 2 emissions while advancing chemical sustainability strategy.

Wireless Alerts and Data Monitoring from BNNO‐MWCNTs/PDMS Composite Film‐Based TENG Integrated Inhaler for Smart Healthcare Application - Venkata Siva Kavarthapu, Mandar Vasant Paranjape, Punnarao Manchi, Anand Kurakula, Jun Kyu Lee, Sontyana Adonijah Graham, Jae Su Yu (Small, 2024)
Abstract In recent years, the implementation of energy‐harvesting technology in medical equipment has attracted significant interest owing to its potential for self‐powered and smart healthcare systems. Herein, the integration of a triboelectric nanogenerator (TENG) is proposed into an inhaler for energy‐harvesting and smart inhalation monitoring. For this initially, barium sodium niobium oxide (Ba 2 NaNb 5 O 15 ) microparticles (BNNO MPs) are synthesized via a facile solid‐state synthesis process. The BNNO MPs with ferroelectricity and high dielectric constant are incorporated into polydimethylsiloxane (PDMS) polymer to make BNNO/PDMS composite films (CFs) for TENG fabrication. The fabricated TENG is operated in a contact‐separation mode, and its electrical output performance is compared to establish the optimal BNNO MPs concentration. Furthermore, multi‐wall carbon nanotubes (MWCNTs), a conductive filler material, are used to enhance the electrical conductivity of the CFs, thereby im proving the electrical output performance of the TENG. The robustness/durability of the proposed BNNO‐MWCNTs/PDMS CF‐based TENG are investigated. The proposed TENG device is demonstrated to harvest electrical energy from mechanical motions via regular human activities and power portable electronics. The TENG is integrated into the inhaler casing to count the number of sprays remaining in the canister, send the notification to a smartphone via Bluetooth, and harvest energy.

A Polymer‐Sol Binder Realizes Single‐Particle Binding for Nacre‐Like Piezoelectric Nanocomposites and Component‐Integrated Batteries - Shan Wang, Jiarui Yang, Wenrui Cai, Guojiang Wen, Sifan Yang, Kai Ke, Bo Yin, Xuewei Fu (Advanced Energy Materials, 2024)
Abstract Achieving precisely defined and stable component binding is of great interest for composite materials and batteries, but very challenging owing to the lack of effective strategies to manipulate the binder itself. Here, a concept of single‐particle binding (SPB) strategy is proposed based on a polymer‐sol binder to conquer the above challenge. To do that, a polymer‐sol binder is first prepared by dispersing commercial poly(vinylidene fluoride) (PVDF) powder into a mixture of its solvent and non‐solvent with a rational weight ratio of 8:2. Then, by manipulating this PVDF‐sol microfluid, PVDF particles are uniformly and singly introduced onto the surface of other components, such as graphene oxide nanosheets and battery separators. Results further show that the temperature‐induced sol–gel transition of the microfluid finally generates single‐particle fusion and strong component binding with commercial separators (31.6 N m −1 ). Meanwhile, a surface‐swelling model is proposed to u nderstand its binding mechanism. Finally, this unique SPB strategy has been employed to fabricate nacre‐like nanocomposites with advanced self‐polarized piezoelectricity (23.0 mV N −1 ), and component‐integrated batteries with robust separator/electrode interphases. This SPB strategy with the PVDF‐sol binder may inspire significant studies on polymer sol, microfluidics, nanocomposites, battery interfaces and beyond.

Multi‐Objective Bayesian Optimization for Laminate‐Inspired Mechanically Reinforced Piezoelectric Self‐Powered Sensing Yarns - Ziyue Yang, Kundo Park, Jisoo Nam, Jaewon Cho, Yong Jun Choi, Yong‐Il Kim, Hyeon-Soo Kim, Seunghwa Ryu (Advanced Science, 2024)
Piezoelectric fiber yarns produced by electrospinning offer a versatile platform for intelligent devices, demonstrating mechanical durability and the ability to convert mechanical strain into electric signals. While conventional methods involve twisting a single poly(vinylidene fluoride-co-trifluoroethylene)(P(VDF-TrFE)) fiber mat to create yarns, by limiting control over the mechanical properties, an approach inspired by composite laminate design principles is proposed for strengthening. By stacking multiple electrospun mats in various sequences and twisting them into yarns, the mechanical properties of P(VDF-TrFE) yarn structures are efficiently optimized. By leveraging a multi-objective Bayesian optimization-based machine learning algorithm without imposing specific stacking restrictions, an optimal stacking sequence is determined that simultaneously enhances the ultimate tensile strength (UTS) and failure strain by considering the orientation angles of each aligned fiber mat as dis crete design variables. The conditions on the Pareto front that achieve a balanced improvement in both the UTS and failure strain are identified. Additionally, applying corona poling induces extra dipole polarization in the yarn state, successfully fabricating mechanically robust and high-performance piezoelectric P(VDF-TrFE) yarns. Ultimately, the mechanically strengthened piezoelectric yarns demonstrate superior capabilities in self-powered sensing applications, particularly in challenging environments and sports scenarios, substantiating their potential for real-time signal detection.

Bioinspired Multistimulus‐Responsive Piezoelectric Polymeric Nanoheterostructures via Interface‐Confined Configurations - Defeng Cui, Jie Wang, Mengxia Zhang, Tao Cheng, Nan Yue, Donghai Qiu, Bo Lü, Binbin Dong (Advanced Functional Materials, 2024)
Abstract Developing polymer‐based piezoelectric materials with multistimulus responsiveness is highly desirable for advancing multi‐source energy harvesting in wearable electronics. Inspired by the multifunctionality of muscle fibers, a nanostructure interface engineering strategy to create piezoelectric polymeric nanoheterostructures (PNHs) with remarkable responsiveness to both mechanical and nonmechanical contactless stimuli is introduced. Through precise interfacing of polymer nanofibers with nanoparticles via multiscale‐regulated interface electrostatic and chemical interactions, the study achieves a controlled assembly of stabilized and hierarchically organized nanoheterostructures featuring unique interface‐confined configurations. These configurations induce in situ stabilized dipole orientation and significant geometric stress nano‐confinement at interfaces, crucial for amplifying electricity generation. Compared to conventional polymer nanocomposites, engineered PNHs exhibit dramatically enhanced piezoelectricity, boasting a higher sensitivity of 1065 mV kPa −1 and piezoelectric coefficient of 76.2 pC N −1 . Furthermore, PNHs demonstrate superior thermo‐actuated electricity generation under temperature fluctuations through cooperative spontaneous polarizations of constituent nanostructures, yielding a higher pyroelectric coefficient of 3.13 µC m 2 K −1 . Additionally, the design enables photothermally‐activated switchable electricity generation and light‐energy harvesting, achieving a photo‐electric conversion efficiency tenfold higher than nanocomposites. This effective and versatile approach inspires the development of multi‐responsive nanogenerators for multi‐energy harvesting and self‐powered multistimulus‐sensing applications.

Mixed‐Dimensional All‐Organic Polymer Heterostructures with Enhanced Piezoelectricity - Wangwei Lian, Leiyang Wang, Jie Wang, Tao Cheng, Kun Dai, Bo Lü, Chuntai Liu, Caofeng Pan (Advanced Functional Materials, 2024)
Abstract Enhancing the piezoelectricity of polymers while maintaining all components organic is still challenging but significantly important for developing flexible wearable energy harvesters and self‐powered devices. Here, a novel and versatile strategy is introduced to construct mixed‐dimensional all‐organic polymer heterostructures (MPHs) for enhanced piezoelectricity. By combining all‐polymer 1D nanofibers (NFs) with 2D crystals through epitaxial crystallization‐driven assembly (ECA), MPHs are engineered to capitalize on the synergistic effects of both dimensional nanostructures. The intrinsic piezoelectric activity of 1D NFs is amplified by the growth of 2D crystals, enhancing force‐sensitivity and overall piezoelectricity. The mixed‐dimensional assembly not only enables controlled in‐situ growth of MPHs, but also simultaneously induces preferential formation of electroactive phases through solvent‐induced phase transition. By modulating the epitaxial growth of 2D crystals on 1D NFs, effective tuning of MPH growth amount and morphology is achieved, resulting in significant improvements in deformability, dipole polarization, and durability. MPHs exhibit remarkable piezoelectric improvements, achieving higher output under lower‐level forces with a record‐high sensitivity of ≈670 mV kPa −1 . Their superior responsivity enables the development of self‐powered wireless wearable motion‐monitoring systems for real‐time physiological movement detection and analysis. This work inspires the development of all‐organic piezoelectric devices for innovative flexible energy‐harvesting and sensing applications.

Programming Piezoelectric Phase of Poly(Vinylidene Fluoride) via Hybrid Metal Halide Perovskite for Enhanced Electromechanical Performance - Yong‐Ji Gong, Zhigang Li, Tian‐Meng Guo, Chen Zhao, Ying Zhang, Min He, Jie Yu, Wei Li (Advanced Energy Materials, 2024)
Abstract Fluoropolymers and metal halide perovskites (MHPs), as two classes of important piezoelectric materials, suffer from active phases through a facile process and brittleness led poor manufacturability, respectively. Here, TMCM‐CdCl 3 /PVDF nanocomposites (TMCM = trimethylchloromethyl ammonium, PVDF = polyvinylidene fluoride) are synthesized to overcome the above shortcomings. The abundant hydrogen (H) and chlorine (Cl) sites in TMCM‐CdCl 3 can interlock with H and fluorine (F) atoms within PVDF via C─H···Cl and C─H···F interactions. This programming effect augments the dipole alignment and consequently promotes the formation of polar phases within PVDF. The devices made by these nanocomposites exhibit high energy harvesting properties surpassing established MHP/PVDF analogues, and prominent performance in sensing delicate human motions. Moreover, the devices show exceptional capabilities for detecting underwater ultrasound waves. The signal intensity is ≈4 times that of commerci al PVDF film devices, and the frequency distortion is only a quarter of that observed in commercial ceramic transducers. This study opens up new possibilities for developing high‐performance piezoelectric nanocomposites and the creation of advanced electromechanical devices.

Electrospun Polyvinylidene Fluoride Nanogenerator with Hydrophobic Properties and Enhanced Energy Harvesting for Wearable and Wireless Sensing - Zhou, Jie; Xu, Liqiang; Zhang, Lun; Zhang, Jihai; Zhang, Aimin (ACS APPLIED ELECTRONIC MATERIALS, 2024)
Polyvinylidene fluoride (PVDF) has better compliance and mechanical processing performance than traditional piezoelectric ceramic materials and is easy to process and mold. However, this also sacrifices part of the piezoelectric properties of PVDF. Therefore, polymer-piezoelectric ceramic composites were developed to balance this problem. Herein, self-polarized PVDF piezoelectric fibers with stable hydrophobicity and improved piezoelectric characteristics were prepared by using a quick and efficient electrostatic spinning process, specifically, dimethoxymethylvinylsilane-modified BaTiO3 (M-BTO) as a piezoelectric enhancer, which improved the dispersion of the filler and the piezoelectricity of the composites. As a result, the output voltage and current of the M-BTO/PVDF composite piezoelectric fiber reached 17.2 V and 421.1 nA, respectively. Moreover, the hydrophobic surface of the composite gives it excellent self-cleaning properties. In view of the excellent electromechanical convers ion ability of the composites, the prepared piezoelectric nanogenerator can be used to detect different physiological signals in the human body. A simple wireless system is set up to enable the wireless transmission of piezoelectric signals. This study highlights an interfacial modification approach for the preparation of high-performance piezoelectric energy harvesters, providing a practical and potentially useful basis for human-machine interface applications.

Piezoelectric Outputs of Electrospun PVDF Web as Full-Textile Sensor at Different Mechanical Excitation Frequencies - Meng, Fenye; Hu, Jiyong (POLYMERS, 2024)
With the increasing application of electrospun PVDF webs in piezoelectric sensors and energy-harvesting devices, it is crucial to understand their responses under complex mechanical excitations. However, the dependence of the piezoelectric effect on mechanical excitation properties is not fully comprehended. This study aims to investigate the piezoelectric output of randomly oriented electrospun PVDF nanofiber webs fabricated through different electrospinning processes at various mechanical excitation frequencies. The electrospun PVDF web was sandwiched between two textile electrodes, and its piezoelectric output as a full-textile sensor was measured across a frequency range from 0.1 Hz to 10 Hz. The experimental results revealed that the piezoelectric output of the electrospun PVDF web exhibited a nearly linear increase at excitation frequencies below 1.0 Hz and then reached an almost constant value thereafter up to 10 Hz, which is different from the hybrid PVDF or its copolymer web. Furthermore, the dependency of the piezoelectric output on the excitation frequency was found to be influenced by the specific electrospinning process employed, which determined the crystalline structure of electrospun PVDF nanofibers. These findings suggest that determining an appropriate working frequency for randomly oriented electrospun PVDF nanofiber webs is essential before practical implementation, and the piezoelectric response mode in different mechanical activation frequency ranges can be used to detect different human physiological behaviors.

Self-powered piezoelectric sensor based on BaTiO3/MWCNTs/PVDF electrospun nanofibers for wireless alarm system - Liu, Lei; Li, Xueying; Gang, Yongfeng; Cui, Xin; Fan, Bo; Dan, Yuanyuan; Fang, Jiwen (JOURNAL OF PHYSICS D-APPLIED PHYSICS, 2024)
The piezoelectric constant of polyvinylidene fluoride (PVDF) is inferior to that of piezoelectric ceramics, which will impede the efficient application in smart systems. In this work, we modulated the content of BaTiO3/multi-wall carbon nanotubes (MWCNTs) in the BaTiO3/MWCNTs/PVDF electrospun nanofibers to facilitate the beta phase formation in the PVDF to enhance the piezoelectric properties of BaTiO3/MWCNTs/PVDF films. The BaTiO(3 )combined with MWCNTs through chemical bands can enhance the electrostatic interaction at the vicinity of BaTiO3-PVDF interface to induce augmentation of the local conformational disorder and result in the enhanced nucleation and stabilization of beta phase in the BaTiO3/MWCNTs/PVDF films. When the ratio between BaTiO3 and MWCNTs is about 3:1, the PVDF-BM-3 can deliver the output voltage of 39.5 V under 250 kPa with a frequency of 10 Hz. The PVDF-BM-3 electrospun nanofibers as triggers used in the wireless alarm system can achieve comparable sensitivity und er different external stresses. This work paves a new promising pathway for self-powered piezoelectric sensors in the Internet of Things.

Electrospun PVDF and composite nanofiber: Current status and future prescription towards hybrid Piezoelectric nanogenerators - Dani, Sanskruti Smaranika; Sundaray, Bibekananda; Nayak, Sanjay kumar; Mohanty, Smita (MATERIALS TODAY COMMUNICATIONS, 2024)
Piezoelectricity is extensively studied for the fabrication of portable, flexible, wearable, lightweight, eco-friendly energy harvesting systems, which can produce energy from waste. Nanostructured materials help to boost energy efficiency due to their large surface-to-volume ratio and provide necessary adaptability and user-friendliness in day-to-day life. So far, piezoelectric Polyvinylidene fluoride (PVDF) nanofiber materials have promising candidates in textile industries, health care systems, tissue engineering, drug delivery, pollution control, energy harvesting, and sensing applications. Electrospinning serves as a practical, affordable, and comparatively easy approach to producing highly crystalline-aligned PVDF nanofibers from nano to micro-orders. This review focuses on the key parameters such as piezoelectric responses in PVDF, electrospinning fabrication of PVDF nanofiber, computational modelling of PVDF system, ongoing advancements in PVDF and nanocomposite fibrous scaffol ds as well as the existing challenges in electrospinning technology. Additionally, recently reported PVDF based hybrid piezoelectric nanogenerators that combine triboelectric and pyroelectric mechanism and serve as high-performance self-powered sophisticated energy harvesting systems have also been reviewed. Moreover, the key aspect of this review is a comprehensive understanding of electrospun PVDF nanocomposite fiber to generate new perspectives toward the futuristic application of piezoelectric energy harvesting technology.

Designing PVdF-HFP/BTO Piezoelectric Sensor based Sensing System for Detecting Volume Expansion of Battery Cell (Ceramist, 2024)
Piezoelectric sensor can be used to inform the battery safety by detecting the battery swelling induced pressure. In this study, a piezoelectric sensing material, sensor unit, and sensing system were developed using piezoelectric polymer polyvinylidene fluoride-co-hexafluoropropylene(PVdF-HFP) and piezoelectric ceramic BaTiO3(BTO). Free-standing PVdF-HFP/BTO composite nanofiber web was retrieved as the sensing material due to the nanofiber web-based flexibility and the molecular arrangement driven piezoelectric performances. The PVdF-HFP/BTO composite nanofiber web-based sensor was employed in the automatic pressure sensing system, which provides the visual and audible signals once the pressure exceeds a certain limit. Our work demonstrates that the design of new piezoelectric sensing system is a fruitful pathway to sensing the battery malfunctions.

배터리 셀의 부피 팽창 감지용 PVdF-HFP/BTO 압전 센서 기반 압력 감지 시스템 설계 (세라미스트, 2024)
Piezoelectric sensor can be used to inform the battery safety by detecting the battery swelling induced pressure. In this study, a piezoelectric sensing material, sensor unit, and sensing system were developed using piezoelectric polymer polyvinylidene fluoride-co-hexafluoropropylene(PVdF-HFP) and piezoelectric ceramic BaTiO3(BTO). Free-standing PVdF-HFP/BTO composite nanofiber web was retrieved as the sensing material due to the nanofiber web-based flexibility and the molecular arrangement driven piezoelectric performances. The PVdF-HFP/BTO composite nanofiber web-based sensor was employed in the automatic pressure sensing system, which provides the visual and audible signals once the pressure exceeds a certain limit. Our work demonstrates that the design of new piezoelectric sensing system is a fruitful pathway to sensing the battery malfunctions.

Synthesis and characterization of barium titanate nanoplatelets/polyvinylidene fluoride nanocomposite for piezoelectric properties - Aldulaimi, Hussein; Pircheraghi, Gholamreza; Nemati, Ali (POLYMER COMPOSITES, 2024)
Barium titanate (BaTiO3) nanostructures with a tetragonal structure have unique mechanical and piezoelectric properties. BaTiO3 nanoplatelets (BTNPs) were synthesized via the precipitation of the hydroxide (Ba-Ti-OH) precursor, which was subsequently subjected to hydrothermal treatment. Polyvinylidene fluoride (PVDF) granules and BTNPs powder were compounded through melt-mixing within a laboratory internal mixer to PVDF/BTNP nanocomposite. The dispersion of BTNPs were analyzed using FE-SEM images. The examination of the polycrystalline structure of a PVDF/BTNP nanocomposite involved the utilization of FTIR, DSC, and XRD measurements. Further, the tensile test was carried out to study the mechanical properties of the nanocomposites. The piezoelectric tests showed that the PVDF nanocomposite with 10 wt.% of BTNP exhibited the highest output voltage and current due to its maximum crystallinity. The measured current increased from 0.03 mu A for PVDF to 0.22 mu A for PVDF/BTNP nanocomposite and further to 0.34 after polling. PVDF's piezoelectric properties experienced an 11-fold enhancement due to alterations in its crystalline structure. Power density improved by 644% (7.5 times), and piezoelectric sensitivity rose by 173%. Consequently, the PVDF/BTNP nanocomposite demonstrates significant potential for applications in electronics and energy harvesting.Highlights Unique Tetragonal nanoplatelets produced via controlled BTNP synthesis. 10% BTNP enhances nanocomposite crystallinity by 22.7% PVDF-10 displays increase in both voltage and current, enhancing piezoelectricity. Nanocomposites show promise for energy and electronics.Preparation of Barium titanate nanoplatelets/PVDF nanocomposites for piezoelectric properties. image

Construction of PVDF-HKUST-1/BiVO4 hybrid electrospun flexible fiber membrane for enhanced piezo-photocatalytic reduction performance of Cr (VI) - Huang, Qiqi; Zhu, Fuxiao; Xiao, Feiyan; Zhang, Gongliang; Hou, Hongman; Bi, Jingran; Yan, Shuang; Hao, Hongshun (COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, 2024)
For the practical implementation of Cr(VI) removal, effective and recyclable water treatment technology is essential. Polarized electric fields inside piezoelectric materials have proved to be a promising technique for facilitating photogenerated charge separation. In this work, Z-scheme heterojunction photocatalyst HKUST-1/ BiVO4 and organic piezoelectric material PVDF were combined through electrospinning to create a novel flexible fiber PVDF-HKUST-1/BiVO4 (PVDF-HV) piezo-photocatalyst membrane. When the amount of HKUST-1/BiVO4 powder was 2.4% and the diameter of the obtained fiber film was 10 cm, the optimal reduction efficiency can be achieved by the piezoelectric photocatalytic reduction in solution with initial pH=2, and the piezophotocatalytic efficiency of PVDF-HV reached up to 85.33% within 120 min, which was about 1.35 times and 2.19 times greater than that of single photocatalysis and piezoelectric catalysis, respectively. It successfully promoted photo charge separation bas ed on the piezoelectric field in PVDF and the heterojunction produced between HKUST-1 and BiVO4. This research developed an efficient strategy for multi-path collection and exploitation of natural solar energy and vibration energy to boost photoactivity.

Enhancing the piezoelectric performance of composite PVDF flexible films through optimizing β phase content, investigating additive effects, step-wise polarization, and thermal pressing time for energy harvesting applications - Oflaz, Kamil; Ozaytekin, Ilkay; Sadasivuni, Kishor Kumar (JOURNAL OF APPLIED POLYMER SCIENCE, 2024)
Polyvinylidene fluoride (PVDF), known for its piezoelectric versatility, emerges as a key contender for advancing efficient and sustainable energy harvesting in nanogenerators. This study explores the potential enhancement of piezoelectric properties in flexible PVDF polymers, employing a comprehensive approach through the solution casting method. The investigation integrates diverse additives, thermal treatments, and polarization methods to optimize performance, focusing on the impact of the beta phase transition on electrical voltage generation. Utilizing the Taguchi experimental design, the study identifies optimal conditions for the composite PVDF film (OPT-PVDF) through FT-IR, XRD, and DSC analyses, with output voltage measurements confirming superior performance compared to pure PVDF (P-PVDF). Specifically, BN-doped PVDF films, with an 80% beta phase content, achieve an impressive 6.48 V output voltage. This research underscores PVDF's potential for energy harvesting, emphasizing the pivotal role of optimizing beta phase content, additive strategies, and the effects of polarization and thermal treatments. The study further evaluates the effect and necessity of subsequent thermal treatment and step-wise polarization effects on the composite PVDF film material. The findings indicate that BN-doped composite PVDF films, produced under optimal conditions, exhibit advanced piezoelectric properties.

Spatially Confined MXene/PVDF Nanofiber Piezoelectric Electronics - Zhang, Jieling; Yang, Tao; Tian, Guo; Lan, Boling; Deng, Weili; Tang, Lihua; Ao, Yong; Sun, Yue; Zeng, Wanghong; Ren, Xiarong; Li, Zhaoyu; Jin, Long; Yang, Weiqing (ADVANCED FIBER MATERIALS, 2024)
Piezoelectric nanofibers have received extensive attention in the field of electronic devices, but they are still restricted for further development, due to their limited dipole arrangement. Herein, we propose spatially confined MXene/polyvinylidene fluoride (PVDF) nanofibers for piezoelectric application, with dual functions of pressure sensing and energy harvesting. The spatial confinement of MXene/PVDF nanofibers can actively induce the optimally aligned -CH2-/-CF2- dipoles of PVDF and dramatically boost spontaneous polarization for piezoelectric enhancement. The voltage and current generated by fabricated MXene/PVDF (0.8 wt%) nanofiber piezoelectric electronic devices are respectively 3.97 times and 10.1 times higher than those generated by pure PVDF nanofibers. Based on these results, the developed bifunctional electronic devices are applied to monitor various human movements and to harvest energy. Notably, the results of this work allow for the development of nanofibers with exce llent piezoelectric performance using a spatial confinement mechanism.

Tailoring Piezoelectricity of 3D Printing PVDF-MoS2 Nanocomposite via In Situ Induced Shear Stress - Rupom, Rifat Hasan; Islam, Md Nurul; Demchuk, Zoriana; Advincula, Rigoberto; Dahotre, Narendra B.; Jiang, Yijie; Choi, Wonbong (ACS APPLIED NANO MATERIALS, 2024)
3D printing of unique structures with tunable properties offers significant advantages in the fabrication of complex and customized electronic devices. This study introduces a process-microstructure-property-guided manufacturing route to fabricate PVDF-2D MoS2 piezoelectric nanocomposites with tunable piezoelectric properties without having a postprocess. We control PVDF's microstructure through direct ink writing (DIW) 3D printing while tuning PVDF-MoS2 interfacial strain by controlling rheology and 3D printing parameters, such as nozzle size and printing speed. Our approach demonstrates tunable piezoelectricity in PVDF-MoS2, achieving a 15-fold increase in the piezoelectric coefficient (d(33)) at a printing-induced shear stress of 6685 Pa. This enhancement arises from the electrostatic interactions between PVDF and MoS2 and the filler distribution and alignment caused by the in situ shear stress in 3D printing, as confirmed by XPS and Raman mapping analyses. Our findings advance the understanding of piezoelectric mechanisms in PVDF-based nanocomposites, laying the foundation for 3D printing of piezoelectric sensors in wearable device applications with enhanced performance and customization capabilities.

Chitosan-Doped PVDF Film with Enhanced Electroactive β Phase for Piezoelectric Sensing - ["Shengyang Zhou", "Hongjian Zhang", "Changzhou Du", "Ming Liu", "Li Liu", "Yong Zhang"] (ACS Applied Electronic Materials, 2024)
Polymer-based piezoelectric composites have shown a large potential in various fields of wearable electronics, man–machine interaction, transducers, etc., due to their integrated advantages of high piezoelectric properties, benign flexibility, and pressure sensitivity. As the representative polymer matrix in piezoelectric composites, polyvinylidene fluoride (PVDF) is characterized by its intrinsic piezoelectric response induced via the existence of ferroelectric β and γ phases. However, the most stable phase at ambient temperature and pressure is the nonpolar and paraelectric α phase, which serves as a long-standing issue. Herein, chitosan was introduced into the PVDF matrix to promote the transition from α phase to β phase via the interaction between the –OH and –NH 2 groups in chitosan and the H and F atoms in PVDF. As evidenced, the portion of the β phase increased from 47.9 to 63.7%. An electrospinning technique was adopted to prepare PVDF/chitosan composites with a chitosan conten

Tough, Antifreezing, and Piezoelectric Organohydrogel as a Flexible Wearable Sensor for Human–Machine Interaction - ["Yongdong Shi", "Youjun Guan", "Mingjie Liu", "Xinchang Kang", "Yu Tian", "Weicheng Deng", "Peng Yu", "Chengyun Ning"] (ACS Nano, 2024)
Piezoelectric hydrogel sensors are becoming increasingly popular for wearable sensing applications due to their high sensitivity, self-powered performance, and simple preparation process. However, conventional piezoelectric hydrogels lack antifreezing properties and are thus confronted with the liability of rupture in low temperatures owing to the use of water as the dispersion medium. Herein, a kind of piezoelectric organohydrogel that integrates piezoelectricity, low-temperature tolerance, mechanical robustness, and stable electrical performance is reported by using poly(vinylidene fluoride) (PVDF), acrylonitrile (AN), acrylamide (AAm), p -styrenesulfonate (NaSS), glycerol, and zinc chloride. In detail, the dipolar interaction of the PVDF chain with the PAN chain facilitates the crystal phase transition of PVDF from the α to β phase, which endows the organohydrogels with a high piezoelectric constant d 33 of 35 pC/N. In addition, the organohydrogels are highly ductile and can withsta

A high performance nanocellulose-PVDF based piezoelectric nanogenerator based on the highly active CNF@ZnO via electrospinning technology - Qingtao Zhu, Xinyi Song, Xianfen Chen, Duoduo Li, Xue Tang, Jiabin Chen, Quanping Yuan (Nano Energy, 2024)

A novel centrifugal electrospinning design for preparing of high alignment β-phase PVDF nanofibers for high-performance piezoelectric nanogenerators - Omar N. Alqallab, Mohammad Hafizuddin Hj Jumali (Polymer, 2024)

Insights into Polymorphic Transition of PVDF during Nonsolvent-Induced Phase Separation - ["Zhanbin Qiu", "Tingping Lei", "Shuiping Li", "Xiaomei Cai", "Kai Yang"] (Macromolecules, 2024)
Nonsolvent-induced phase separation (NIPS) is a facile and cost-effective technique for the efficient fabrication of multifunctional polyvinylidene fluoride (PVDF) membranes. However, the polymorphic transition of PVDF during this process is not well understood, although different interpretations have been proposed. Here, the polymorphism of solution-cast PVDF films and the corresponding NIPS membranes has been investigated. Results show that the use of polar aprotic solvents is normally unable to induce the α → β phase transformation in the cast films, whereas immersing the cast wet films in a nonsolvent water bath (forming the NIPS membranes), the β phase emerges, revealing that both solvent and nonsolvent are crucial for polymorphic transition during NIPS. Further experiments show that (1) a low-temperature bath, a long immersion duration, and a suitable solution concentration can promote the β phase formation; (2) solvents having large dipole moment (μ), hydrogen-bond accepting pow

Enhanced energy density in piezoelectric PVDF-polymer nanocomposite via multiple mechanism synergetic action - Xiaoting Yuan, Zifeng Mai, Huan Li, Xiangyu Gao, Ao Yan, Dongjie Jiang, Xunjie Wei, Hongqi Jiang (Nano Energy, 2024)

Enhanced output performance piezoelectric nanogenerators based on highly polarized PVDF/TBAHP tree-like nanofiber membranes for energy harvesting - Yixia Zhao, Mengge Jia, Xiaoyu Wang, Xiaobin Sun, Zongjie Li (Polymer, 2024)

Lightweight, Self-Poled, Flexible Piezoelectric Tungsten Disulfide Quantum Dots-Reinforced PVDF-HFP-Based Nanogenerator - ["Deepak Kashyap", "Avanish Kumar Srivastava", "Manoj Kumar Gupta"] (ACS Applied Electronic Materials, 2024)
Herein, we reported the fabrication of a highly flexible, sensitive, lightweight, self-poled, hybrid tungsten disulfide (WS 2 ) quantum dots-filled poly(vinylidene fluorideco -hexafluoropropene) (PVDF-HFP) nanocomposite-based piezoelectric nanogenerator device with high output performance. Highly uniform WS 2 quantum dots with an average diameter of 7–8 nm were synthesized from the hydrothermal route and an enhanced piezoelectric β-phase of PVDF-HFP was obtained through the polar DMF solvent and in situ electrical poling. Structural and morphological investigation revealed the formation of the pure phase of the WS 2 QDs-PVDF-HFP nanocomposite and β-phase of PVDF-HFP. Piezoelectric force microscope analysis revealed a very high piezoelectric charge coefficient ( d 33 ) of ∼294.55 pm/V from single WS 2 QDs. The flexible transparent piezoelectric nanogenerator fabricated from the WS 2 QDs-PVDF-HFP nanogenerator produced a remarkably high output voltage and output current density of about

Boosting the Piezoelectric Response and Interfacial Compatibility in Flexible Piezoelectric Composites via DET-Doping BT Nanoparticles - ["Li Liu", "Hongjian Zhang", "Shengyang Zhou", "Changzhou Du", "Ming Liu", "Yong Zhang"] (Polymers, 2024)
With the advent of the Internet of Things, self-powered wearable sensors have become increasingly prevalent in our daily lives. The utilization of piezoelectric composites to harness and sense surrounding mechanical vibrations has been extensively investigated during the last decades. However, the poor interface compatibility between ceramics nanofillers and polymers matrix, as well as low piezoelectric performance, still serves as a critical challenge. In this work, we employed Di(dioctylpyrophosphato) ethylene titanate (DET) as the coupling agent for modifying barium titanate (BTO) nanofillers. Compared to the BTO/PVDF counterpart, the DET-BTO/PVDF nanofibers exhibit an augmented content of piezoelectric β phase (~85.7%) and significantly enhanced stress transfer capability. The piezoelectric coefficient (d33) is up to ~40 pC/N, which is the highest value among reported BTO/PVDF composites. The piezoelectric energy harvesters (PEHs) present benign durability and attain a high instant

PVDF-Based Piezo-Catalytic Membranes—A Net-Zero Emission Approach towards Textile Wastewater Purification - ["Amna Siddique", "Hifza Nawaz", "Shumaila Razzaque", "Anila Tabasum", "Hugh Gong", "Humaira Razzaq", "Muhammad Umar"] (Polymers, 2024)
Among the various water purification techniques, advancements in membrane technology, with better fabrication and analysis, are receiving the most research attention. The piezo-catalytic degradation of water pollutants is an emerging area of research in water purification technology. This review article focuses on piezoelectric polyvinylidene difluoride (PVDF) polymer-based membranes and their nanocomposites for textile wastewater remediation. At the beginning of this article, the classification of piezoelectric materials is discussed. Among the various membrane-forming polymers, PVDF is a piezoelectric polymer discussed in detail due to its exceptional piezoelectric properties. Polyvinylidene difluoride can show excellent piezoelectric properties in the beta phase. Therefore, various methods of β-phase enhancement within the PVDF polymer and various factors that have a critical impact on its piezo-catalytic activity are briefly explained. This review article also highlights the major

Enhanced Hydrogen Evolution in Porous and Hybrid g‐C3N4/Pt‐PVDF Electrospun Membranes via Piezoelectricity from Water Flow Energy - ["Mengmeng Chen", "Neng Hu", "Weijia Wang", "Lin Lei", "Huiqing Fan", "Peter Müller‐Buschbaum", "Qi Zhong"] (Advanced Functional Materials, 2024)
Abstract Inspired from seaweed swayed by waves, the enhanced hydrogen evolution is realized in porous and hybrid g‐C 3 N 4 /Pt‐PVDF electrospun membranes via piezoelectricity from water flow energy. The membranes are fabricated by dispersing g‐C 3 N 4 /Pt into the mixed solution of PVDF and PEO, followed by electrospinning and selective removal of PEO. By changing the PEO amount, the pore size in nanofibers is adjusted. Due to the hydrogen bonding between g‐C 3 N 4 /Pt and PVDF, the β phase of PVDF is increased, beneficial for the piezoelectricity performance. When the electrospun membranes are exposed to water flow, an additional potential field is triggered due to the deformation of PVDF. It not only eases the photogeneration of charge carriers from g‐C 3 N 4 /Pt but also hinders their recombination. The prolonged lifetime significantly improves the photocatalytic water splitting of g‐C 3 N 4 /Pt under visible light. The hydrogen evolution in the electrospun membranes (PVDF to PEO =

Enhanced Piezoelectric Energy Harvester by Employing Freestanding Single‐Crystal BaTiO3 Films in PVDF‐TrFE Based Composites - ["Ruobo Peng", "Butong Zhang", "Guohua Dong", "Yinghui Wang", "Guannan Yang", "Jie Zhang", "Bin Peng", "Yanan Zhao"] (Advanced Functional Materials, 2024)
Abstract Advancements in wearable electronics and Internet of Things (IoT) sensors have catalyzed the need for effective micro‐energy harvesting. Piezoelectric nanogenerators (PENGs) are ideal due to their high conversion efficiency and durability. However, the contrast between the high piezoelectric coefficients of brittle inorganic ceramics and the lower coefficients of superior flexibility and biocompatibility of organic polymers poses a significant challenge. This work introduces a novel multilayer composite PENG, integrating a single‐crystal BaTiO 3 (BTO) film between poly(vinylidene fluoride‐co‐trifluoroethylene) (PVDF‐TrFE) layers. The PVDF‐TrFE/BTO/PVDF‐TrFE PENGs demonstrate substantially improved energy harvesting performance, with outputs reaching up to 15.1 V, 2.39 µA, and power density of 17.33 µW cm −2 during bending deformation. This power density represents a significant increase compared to pure PVDF‐TrFE and nanoparticle BTO‐doped PVDF‐TrFE PENGs. Durability tests sho