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Integrating energy harvesters with energy storage devices helps enhance energy utilization efficiency. The requirement for external power sources in energy storage devices can also be addressed by the development of an all‐in‐one single system. Vegetable peels can be used as piezoelectric energy harvesters due to the generation of electric dipole within cellulose. The self‐discharge processes cause open circuit potential decay, resulting in a loss of energy stored within the cell. The self‐discharge rate can be controlled by using a piezoelectric separator. This work used garlic skins as a piezoelectric separator, which helped delay the self‐discharge rate. The supercapacitor using Ni−Mn oxide as positive and Fe−Ni sulfide/RGO as negative electrode materials was fabricated with garlic skin as a separator. The device was charged from an initial OCP of ~0.15–~0.37 V in ~ 4 sec by finger tapping. The OCP decay rate was reduced by~88 % compared to that of using the Whatmann separator. The fabricated Ni−Mn oxide RGO/garlic skin/FeS2 RGO exhibited ~72.2 W h kg−1 energy density at a power density of ~2 kW kg−1 in an operated potential window of ~2 V. This research provides a cost‐effective method for developing piezoelectric supercapacitor with low self‐discharge rate. [ABSTRACT FROM AUTHOR]

Redox‐active azo compounds are emerging as promising cathode materials due to their multi‐electron redox capacity and fast redox response. However, their practical application is often limited by low output voltage and poor thermal stability. Herein, we use a heteroatomic substitution strategy to develop 4,4′‐azopyridine. This modification results in a 350 mV increase in reduction potential compared to traditional azobenzene, increasing the energy density at the material level from 187 to 291 Wh kg−1. The introduced heteroatoms not only raise the melting point of azo compounds from 68 °C to 112 °C by forming an intermolecular hydrogen‐bond network but also improves electrode kinetics by reducing energy band gaps. Moreover, 4,4′‐azopyridine forms metal‐ligand complexes with Zn2+ ions, which further self‐assemble into a robust superstructure, acting as a molecular conductor to facilitate charge transfer. Consequently, the batteries display a good rate performance (192 mAh g−1 at 20 C) and an ultra‐long lifespan of 60,000 cycles. Notably, we disclose that the depleted batteries spontaneously self‐charge when exposed to air, marking a significant advancement in the development of self‐powered aqueous systems. [ABSTRACT FROM AUTHOR]

The development of self‐charging supercapacitor power cells (SCSPCs) has profound implications for smart electronic devices used in different fields. Here, we epitaxially electrodeposited Mo‐ and Fe‐codoped MnO2 films on piezoelectric ZnO nanoarrays (NAs) grown on the flexible carbon cloth (denoted ZnO@Mo‐Fe‐MnO2 NAs). A self‐charging supercapacitor power cell device was assembled with the Mo‐ and Fe‐codoped MnO2 nanoarray electrode and poly(vinylidenefluoride‐co‐trifluoroethylene) (PVDF‐Trfe) piezoelectric film doped with BaTiO3 (BTO) and carbon nanotubes (CNTs) (denoted PVDF‐Trfe/CNTs/BTO). The self‐charging supercapacitor power cell device exhibited an energy density of 30 μWh cm−2 with a high power density of 40 mW cm−2 and delivered an excellent self‐charging performance of 363 mV (10 N) driven by both the piezoelectric ZnO nanoarrays and the poly(vinylidenefluoride‐co‐trifluoroethylene) piezoelectric film doped with BaTiO3 and carbon nanotubes. More intriguingly, the device could also be self‐charged by 184 mV due to residual stress alone and showed excellent energy conversion efficiency and low self‐discharge rate. This work illustrates for the first time the self‐charging mechanism involving electrolyte ion migration driven by both electrodes and films. A comprehensive analysis strongly confirmed the important contribution of the piezoelectric ZnO nanoarrays in the self‐charging process of the self‐charging supercapacitor power cell device. This work provides novel directions and insights for the development of self‐charging supercapacitor power cells. [ABSTRACT FROM AUTHOR]

With the growing demand for new energy storage devices, rechargeable aqueous zinc ion batteries (ZIBs) have attracted widespread attention due to their low cost and high safety. Among the cathode materials for ZIBs, polyanionic–based cathode materials with high voltage, high stability, and low cost have great potential. In this paper, tetragonal Na2VOP2O7 was prepared using a simple sol–gel method. The discharge platform voltage amounted to 1.8 V and had good rate and cycle performance due to the inductive effect of pyrophosphate. Then, a protective layer of Zn–hydroxyapatite (ZnHAP) modification was applied to the cathode surface, which can inhibit the hydrolysis of vanadium ions. The capacity was enhanced by 19 % after modification and the capacity retention after 100 cycles was also higher. Interestingly, the Na2VOP2O7 cathode also possesses a self–charging effect, recovering to 48 % of its initial capacity with an open–circuit voltage (OCV) of 1.1 V within a certain period, and light exposure can reduce the self–charging time by 83 %. These beneficial results indicate that the pyrophosphate bifunctional cathode with inductive effect has a great potential to construct high–voltage and multifunctional zinc ion battery. [ABSTRACT FROM AUTHOR]

With the rapid advances in the Internet of Things, it is possible to construct a self-charging power system integrating a triboelectric nanogenerator (TENG) and supercapacitor (SC), which represents an excellent tool for simultaneous conversion and storage of distributed environmental energy. In particular, the well-researched Ti3C2T x MXene materials for triboelectric nanogeneration lack high and stable power density, mainly due to the charge dissipation effect on their surface. Herein, the effectiveness of MXenes is enhanced by encrusting TiO2 on the inner and outer surfaces via a hydrothermal method. TiO2, which has inherent dielectric properties, could serve the dual function of electron trapping/blocking and surface polarization, mitigating the diffusion and drifting of surficial tribo-charges and thus increasing output TENG performance. An integrated TENG based on MXene/TiO2 composites with a TiO2 concentration of 3 mM has a higher output voltage than a pristine MXene-based TENG (110 V, a 1.83-fold increase) and achieves a maximum instantaneous power density of ∼1440 mW m−2. TiO2 is also conductive to pseudo-faradaic reactions, and the integrated MXene/TiO2 based symmetric SC exhibits an enhanced specific capacitance of 231.08 F g−1 at 1 A g−1, which is 4.52 times that of pristine MXene, with a maximum energy density of 12.74 W h kg−1 at a power density of 483.06 W kg−1. Finally, utilizing polyimide sheets as substrates, the flexible self-charging power system was integrated: the TENG charges the SC up to 0.8 V with a charging/discharging time of 37 s/40 s, showing great promise for the demands of flexible and self-powered electronics. [ABSTRACT FROM AUTHOR]

One of the greatest and most urgent needs of this world is to develop technology in the transport industry that can help to reduce the fossil fuel consumption exponentially. Our world is facing the danger of over exploitation of fossil fuels which in turns contributing a lot of pollution and global warming. Thus, working on a solution to reduce pollution and global warming, Electric bicycle is the perfect solution to reduce the causes. In E bicycle we use Lead acid battery, it is fast being recognized as a sustainable battery option because of its superior performance and life cycle. Therefore, lead acid battery based electric bikes can be major breakthrough in the transport industry. In the present work, we focus to enhance battery life while running, the Dynamo used in this setup to recycle the power for production and consumption simultaneously. [ABSTRACT FROM AUTHOR]

Continuous monitoring of bio/physiological signals will play an essential role in personalized, patient‐centric medicine in the future healthcare industry. One of the challenges involves providing a sustainable, energy‐efficient operation for long‐term monitoring devices. The current technology based on power sources requires periodic replacement. Here, a hybrid film composed of a layer of piezoelectric nanowire (PVDFHFP) and a layer of microgel (pNIPAM‐APBA) is presented that continuously monitors glucose, does not rely on enzymes, is self‐charging, and decouples changes in read‐out signals due to glucose detection from the force is applied to activate self‐charging. By characterizing self‐charging/discharging properties, the operation and sensing mechanism for the nanowire/microgel hybrid film are proposed. A reasonable sensitivity of 70 mV mm−1 with a high linearity value of R2 = 0.9956 is observed. This work demonstrates the potential for use in a self‐charging wearable platform that enables continuous monitoring of bio/physiological signals. [ABSTRACT FROM AUTHOR]

Developing multifunctional energy storage systems with high specific energy, high specific power and long cycling life has been the one of the most important research directions. Compared to batteries and traditional capacitors, supercapacitors possess more balanced performance with both high specific power and long cycle-life. Nevertheless, regular supercapacitors can only achieve energy storage without harvesting energy and the energy density is still not very high compared to batteries. Therefore, combining high specific energy and high specific power, long cycle-life and even fast self-charging into one cell has been a promising direction for future energy storage devices. The multifunctional hybrid supercapacitors like asymmetric supercapacitors, batteries/supercapacitors hybrid devices and self-charging hybrid supercapacitors have been widely studied recently. Carbon based electrodes are common materials used in all kinds of energy storage devices due to their fabulous electrical and mechanical properties. In this survey, the research progress of all kinds of hybrid supercapacitors using multiple effects and their working mechanisms are briefly reviewed. And their advantages and disadvantages are discussed. The hybrid supercapacitors have great application potential for portable electronics, wearable devices and implantable devices in the future.

The rapid development of wearable electronics requires its energy supply part to be flexible, wearable, integratable and sustainable. However, some of the energy supply units cannot meet these requirements at the same time, and there is also a capacity limitation of the energy storage units, and the development of sustainable wearable self-charging power supplies is crucial. Here, we report a wearable sustainable energy harvesting-storage hybrid self-charging power textile. The power textile consists of a coaxial fiber-shaped polylactic acid/reduced graphene oxide/polypyrrole (PLA-rGO-PPy) triboelectric nanogenerator (fiber-TENG) that can harvest low-frequency and irregular energy during human motion as a power generation unit, and a novel coaxial fiber-shaped supercapacitor (fiber-SC) prepared by functionalized loading of a wet-spinning graphene oxide fiber as an energy storage unit. The fiber-TENG is flexible, knittable, wearable and adaptable for integration with various portable electronics. The coaxial fiber-SC has high volumetric energy density and good cycling stability. The fiber-TENG and fiber-SC are flexible yarn structures for wearable continuous human movement energy harvesting and storage as on-body self-charging power systems, with light-weight, ease of preparation, great portability and wide applicability. The integrated power textile can provide an efficient route for sustainable working of wearable electronics.

Herein, a self‐charging mechanism of rechargeable aluminum (Al) batteries with Chevrel phase molybdenum sulfide (Mo6S8) cathode is reported. The results unambiguously reveal that the self‐charging is a spontaneous disproportionation of Al intercalated Mo6S8 originated from the dynamic shift of Al between occupied sites during Al intercalating and resting. The theoretical study indicates that the fully Al intercalated Mo6S8 in the format of Al4/3Mo6S8 is kinetically accessible driven by electrochemical overpotential but thermodynamically unstable due to the repulsion between Al3+ cations. This mechanism is a true self‐charging with no input of any form of energy, thus distinctly superior to the previously reported self‐charging mechanisms. Based on this discovery, a semi‐flow AlMo6S8 battery is designed and demonstrated with long‐lasting discharge capability and high capacity. [ABSTRACT FROM AUTHOR]

In recent years, the development of implantable bioelectronics has garnered significant attention. With the continuous advancement of IoT and information technology, implantable bioelectronics can be utilized more effectively for health monitoring to enhance treatment outcomes, reduce healthcare costs, and improve quality of life. Implantable energy storage devices have been widely studied as critical components for energy supply. Conventional power sources are bulky, inflexible, and potentially contain materials that are dangerous to the body. Meanwhile, human tissues are soft, flexible, dynamic, and closed, which puts new requirements on energy storage devices to improve the safety, stability, and matching of implantable batteries or supercapacitors. Herein, recent advances in state‐of‐the‐art nonconventional power options for implantable electronics, specifically biocompatible, miniaturized, stretchable/deformable, biodegradable/bioresorbable, edible, and injectable energy storage devices, are reviewed in this paper. The material strategy and architectural design of the next‐generation implantable energy storage device are discussed, including the selection principle of electrolytes, the all‐in‐one structure design strategy, and the way to realize self‐charging. Finally, the challenges and prospects of emerging design strategies toward developing next‐generation implantable batteries and supercapacitors for the future are put forward. [ABSTRACT FROM AUTHOR]

Recently, with the continuous development of human society and the continuous innovation of technologies, the intelligence era has arrived. Various intelligent electronic devices continue to be developed, in which flexible wearable electronic devices are highly favored by people. To meet the requirements of the normal operation of intelligent devices, the key point lies in the development of new smart energy storage devices. Accordingly, smart supercapacitors have been widely focused on and studied by researchers recently with the introduction of intelligent functions, such as electrochromism, self‐healing, and shape memory, into supercapacitors to broaden their application fields and promote their smart development. This can meet not only people's energy needs but also people's diverse personality needs and make our life more convenient, fast, and more intelligent than ever. Therefore, it is very important to summarize related work on smart supercapacitors. Although researchers have performed much research on smart supercapacitors, there is still little literature summary on the related work of different smart supercapacitors. Accordingly, this paper mainly introduces the research progress on electrochromic, self‐healing, shape memory, and self‐charging smart supercapacitors in recent years and discusses the development prospects and challenges of smart supercapacitors. [ABSTRACT FROM AUTHOR]

Abstract Recently, with the continuous development of human society and the continuous innovation of technologies, the intelligence era has arrived. Various intelligent electronic devices continue to be developed, in which flexible wearable electronic devices are highly favored by people. To meet the requirements of the normal operation of intelligent devices, the key point lies in the development of new smart energy storage devices. Accordingly, smart supercapacitors have been widely focused on and studied by researchers recently with the introduction of intelligent functions, such as electrochromism, self‐healing, and shape memory, into supercapacitors to broaden their application fields and promote their smart development. This can meet not only people's energy needs but also people's diverse personality needs and make our life more convenient, fast, and more intelligent than ever. Therefore, it is very important to summarize related work on smart supercapacitors. Although researchers have performed much research on smart supercapacitors, there is still little literature summary on the related work of different smart supercapacitors. Accordingly, this paper mainly introduces the research progress on electrochromic, self‐healing, shape memory, and self‐charging smart supercapacitors in recent years and discusses the development prospects and challenges of smart supercapacitors.

This multilevel inverter type summarizes an output voltage of medium voltage based on a series connection of power cells employing standard configurations of low-voltage components. The main problems of cascaded switched-capacitor multilevel inverters (CSCMLIs) are the harmful reverse flowing current of inductive loads, the large number of switches, and the surge current of the capacitors. As the number of switches increases, the reliability of the inverter decreases. To address these issues, a new CSCMLI is proposed using two modules containing asymmetric DC sources to generate 13 levels. The main novelty of the proposed configuration is the reduction of the number of switches while increasing the maximum output voltage. Despite the many similarities, the presented topology differs from similar topologies. Compared to similar structures, the direction of some switches is reversed, leading to a change in the direction of current flow. By incorporating the lowest number of semiconductors, it was demonstrated that the proposed inverter has the lowest cost function among similar inverters. The role of switched-capacitor inrush current in the selection of switch, diode, and DC source for inverter operation in medium and high voltage applications is presented. The inverter performance to supply the inductive loads is clarified. Comparison of the simulation and experimental results validates the effectiveness of the proposed inverter topology, showing promising potentials in photovoltaic, buildings, and domestic applications. A video demonstrating the experimental test, and all manufacturing data are attached.

Air self‐charging aqueous metal‐ion batteries usually suffer from capacity loss after self‐charging cycles due to the formation of basic salts on cathodes in the near‐neutral electrolytes. Here, air self‐charging Pb/pyrene‐4,5,9,10‐tetraone (PTO) batteries based on proton chemistry are developed in acidic electrolyte. The fast kinetics of H+ uptake/removal endows the battery with enhanced electrochemical performance. Owing to the high standard electrode potential of oxygen in acid electrolyte, the discharged cathodes are spontaneously oxidized by oxygen in air along with H+ extraction and thus achieve self‐charging without external power supply. Notably, the air self‐charging mechanism involved H+‐based redox can effectively avoid the generation of basic salts on self‐charging electrodes and thus guarantee long‐term self‐charging/galvanostatic discharging cycles of Pb/PTO batteries. This work provides a promising strategy for designing long‐cycle air self‐charging systems. [ABSTRACT FROM AUTHOR]

In recent decades, wireless power transfer (WPT) has gained significant interest from both academic and industrial experts. It possesses natural electrical isolation between transmitter and receiver components, ensuring a secure charging mechanism in an underwater scenario. This ground-breaking technology has also enabled power transmission in the deep-sea environment. However, the stochastic nature of the ocean highly influences underwater wireless power transmission and transfer efficiency is not up to that of terrestrial WPT systems. Recently, the research fraternity has focused on WPT in the air medium, while underwater wireless power transfer (UWPT) is challenging and yet to be explored. The major concerns are ocean current disturbance, bio-fouling, extreme pressure and temperature, seawater conductivity and attenuation. Thus, it is essential to address these challenges, which cause a substantial energy loss in UWPT. This study presents a comparison between various WPT techniques and highlights the research contributions in UWPT in recent years. Research and engineering challenges, practical considerations, and applications are analyzed in this review. We have also addressed influencing factors such as coil orientation, coil misalignment and seawater effects in order to realize an efficient and flexible UWPT system. In addition, this study proposes multiple-input and multiple-output (MIMO) wireless power transmission, which can significantly improve the endurance of autonomous underwater vehicles (AUVS). This idea can be applied to the design of an underwater wireless power station for self-charging of AUVs. [ABSTRACT FROM AUTHOR]

Abstract Charging wearable energy storage devices with bioenergy from human‐body motions, biofluids, and body heat holds great potential to construct self‐powered body‐worn electronics, especially considering the ceaseless nature of human metabolic activities. To bridge the gap between human‐body bioenergy and storage of energy, wearable triboelectric/piezoelectric nanogenerators (TENGs/PENGs), biofuel cells (BFCs), thermoelectric generators (TEGs) have been designed to harvest energy from body‐motions, biofluids, and body heat, respectively. Researchers have explored various strategies using bioenergy harvesters to charge wearable supercapacitors and batteries to relieve or even fully eliminate the recharging process from external power stations, thus, making wearable electronics more sustainable, autonomous, and user friendly. In this article, we review the advances in the design of sustainable energy storage devices charged by human‐body energy harvesters. The progress in multifunctional wearable energy storage devices that cater to the easy integration with human‐body energy harvesters will be summarized. Then, the focus is laid on the integrating strategies (single‐cell strategy and separated‐cell strategy), device design, materials selection, and characteristics of different self‐charging human‐body energy harvesting‐storage systems. Finally, the challenges that impede the wide application of human‐body energy harvesters charged supercapacitors/batteries and prospects will be discussed both from materials and structural design aspects.

The fast advancement of flexible electronic technology hastens an ever-growing demand for power sources that are adaptable and flexible, and the arrival of innovative energy harvesting technologies such as triboelectric nanogenerator (TENG) further endow the potable electronics with versatility and sustainability. Herein, polyvinyl alcohol/ polyacrylamide/ zinc sulfate (PPZ) hydrogel was synthesized via an one-step UV-initiated polymerization. The hydrogel demonstrates exceptional tensile properties (with a large strain of 915 % and a corresponding tensile strength of 231 KPa), excellent electrical conductivity and light transmittance. A highly flexible and easily adaptable single-electrode TENG was thus fabricated on the base of the as-synthetized PPZ (PPZ-TENG), where the PPZ hydrogel functions as both the charging layer and current collector. While promoting a high electrical output performance of the PPZ-TENG (an open circuit voltage of 176 V and a power density of 328 mW/m2), the PPZ hydrogel also serves as an efficient ion-conductive electrolyte to construct highly flexible self-charging zinc ion batteries (ZIBs). Besides, highly sensitive strain response toward environmental stimuli was also demonstrated, which makes the integration strategy a promising solution for future development self-powered flexible wearable electronics toward the sustainable monitoring of human vital signs such as pulse and limb movement. [Display omitted] • The PPZ hydrogel was simply synthesized via an one-step UV-initiated polymerization. • PPZ hydrogel-based TENG was designed and assembled which could generate a power density of 328 mW/m2. • The flexible and adaptable TENG was used to human motion sensing and drive zinc-ion batteries. [ABSTRACT FROM AUTHOR]

High-voltage DC (HVDC) circuit breaker is the necessary equipment for multiterminal HVDC grids, which is a prospective power transmission method in the future. Therefore, the research about HVDC interruption ushered in an explosive development in recent years. The mechanical DC circuit breaker based on the precharged capacitor for current commutation and interruption is considered to be one of the most promising HVDC interruption solution. However, the commutation capacitor requires a complicated precharging circuit, especially in high-voltage applications, which brings a great challenge to the promotion of mechanical interruption solution. In this article, a novel self-charging mechanical HVDC circuit breaker is proposed. It utilizes the induced voltage generated by part of current limiting reactor to adaptively charge the commutation capacitor under different fault current conditions without extra auxiliary charging circuit. By investigating the influence of capacitance and inductance on the charging time and current commutation process, the optimized parameters are determined. Then, the breaking performance of proposed HVDC breaker under different rising rates of fault current is evaluated in a two-terminal HVDC system. Finally, a low-power prototype is developed to verify the feasibility of the proposed topology and an improved scheme for rated current breaking is discussed. [ABSTRACT FROM AUTHOR]

Self-charging zinc batteries that combine energy harvesting technology with batteries are candidates for reliable self-charging power systems. However, the lack of rational materials design results in unsatisfactory self-charging performance. Here, a covalent organic framework containing pyrene-4,5,9,10-tetraone groups (COF-PTO) is reported as a cathode material for aqueous self-charging zinc batteries. The ordered channel structure of the COF-PTO provides excellent capacity retention of 98% after 18 000 cycles at 10 A g -1 and ultra-fast ion transfer. To visually assess the self-charging performance, two parameters, namely self-charging efficiency (self-charging discharge capacity/galvanostatic discharge capacity, η) and average self-charging rate (total discharge capacity after cyclic self-charging/total cyclic self-charging time, ν), are proposed for performance evaluation. COF-PTO achieves an impressive η of 96.9% and an ν of 30 mAh g -1 self-charge capacity per hour in 100 self-charging cycles, surpassing the previous reports. Mechanism studies reveal the co-insertion of Zn 2+ and H + double ions in COF-PTO of self-charging zinc batteries. In addition, the C═N and C═O (on the benzene) in COF-PTO are ortho structures to each other, which can easily form metal heterocycles with Zn ions, thereby driving the forward progress of the self-charging reaction and enhancing the self-charging performance., (© 2024 Wiley‐VCH GmbH.)

In recent decades, wireless power transfer (WPT) has gained significant interest from both academic and industrial experts. It possesses natural electrical isolation between transmitter and receiver components, ensuring a secure charging mechanism in an underwater scenario. This ground-breaking technology has also enabled power transmission in the deep-sea environment. However, the stochastic nature of the ocean highly influences underwater wireless power transmission and transfer efficiency is not up to that of terrestrial WPT systems. Recently, the research fraternity has focused on WPT in the air medium, while underwater wireless power transfer (UWPT) is challenging and yet to be explored. The major concerns are ocean current disturbance, bio-fouling, extreme pressure and temperature, seawater conductivity and attenuation. Thus, it is essential to address these challenges, which cause a substantial energy loss in UWPT. This study presents a comparison between various WPT techniques and highlights the research contributions in UWPT in recent years. Research and engineering challenges, practical considerations, and applications are analyzed in this review. We have also addressed influencing factors such as coil orientation, coil misalignment and seawater effects in order to realize an efficient and flexible UWPT system. In addition, this study proposes multiple-input and multiple-output (MIMO) wireless power transmission, which can significantly improve the endurance of autonomous underwater vehicles (AUVS). This idea can be applied to the design of an underwater wireless power station for self-charging of AUVs.

The rapid development of wearable electronics has accelerated the development of wearable energy storage devices. Wearable supercapacitors have aroused widely interest due to their large power density. However, there are still many challenges in the practical application of wearable supercapacitors. This paper summarizes the structure, working mechanism, materials and key parameters of wearable supercapacitors. And we reviewed the challenges of wearable supercapacitors in practical applications, namely safety, mechanical adaptability, self‐charging capability, environmental tolerance, and multifunction. Finally, these challenges are summarized and prospected. We hope to inspire some work to solve the practical application challenges of wearable supercapacitors. [ABSTRACT FROM AUTHOR]

[Display omitted] • HEDs combining EBFCs and SCs are suggested as power source of wearable and implantable devices. • HEDs exhibit exceptional fuel reactivity achieving 0.91 and 0.51 mA/cm2 in GOR and ORR. • HEDs produce power and specific storage capacitance of 0.93 mW/cm2 and 307 mF/cm2 like SCs. • Self-charging of HEDs is observed by unique design using enzyme and mediator in each electrode. • By self-charging effect, OCV of HEDs is well preserved and HEDs can discharge even wiothout fuels. Enzymatic biofuel cells (EBFCs) are promising as a biocompatible power source for implantable and wearable devices, converting chemical energy of body fluids into electricity. However, they have intrinsic limitations, such as low power density and requirement for continuous fuel supply. To overcome the difficulties, hybrid energy devices (HEDs) that are combinative device of supercapacitor (SC) and EBFC are suggested in this study. They consist of anode and cathode including (i) enzymes reacting with respective fuels and (ii) mediators promoting transfer and storage of electrons. As EBFCs, HEDs exhibit exceptional fuel reactivity, achieving 0.91 and 0.51 mA/cm2 in glucose oxidation reaction and oxygen reduction reaction, while they play as SCs with excellent power and specific storage capacitance of 0.93 mW/cm2 and 307 mF/cm2. Moreover, HEDs show self-charging property that is uniquely observed in devices operated by the collaboration of enzyme and mediator. By this benefit, their open circuit voltage is well preserved in absent of fuels, while they can discharge even without supply of fuel. These features are obvious evidence that HEDs can be considered as advanced power sources for implantable and wearable devices. [ABSTRACT FROM AUTHOR]

Timely monitoring of abnormal vibration of machinery in highly harsh environments is essential to ensure the safe operation of mechanical systems. This paper uses a self-charging power module to harvest energy to provide sustainable power for monitoring multidirectional ultra-low frequency mechanical vibrations. The power generation unit consists mainly of a spherical electromagnetic triboelectric hybrid nanogenerator (SETE-HNG). It is equipped with advanced sensing functions to support deep learning to identify signals with different directions of vibration, different frequencies, and different amplitudes of vibration, thereby enhancing the high-precision perception function. The accuracy of the prediction results is as high as 98.6622%, 100%, and 99.3333%, respectively. A Power Management Circuitry (PMC) has been meticulously crafted to maximize the utilization of vibrational energy. It efficiently charges a 40 mAh lithium polymer battery to 3.3 V in just 26 min, all without the requirement of an external power source. This advancement facilitates self-powered Global Positioning System (GPS) tracking of vibrational signals. Moreover, the stored energy is harnessed to energize a microcontroller and a low-power Bluetooth module. This enables real-time monitoring of mechanical vibrations via a mobile phone. The design presented in this paper is a testament to the potential of self-powered multidirectional mechanical vibration monitoring, contributing significantly to the safety and efficiency of mechanical systems. The design in this paper enables self-powered monitoring of abnormal vibrations in mechanical systems in extremely harsh environments, thus ensuring the safe operation of equipment. [Display omitted] • Large-scale vibration energy harvesting provides an innovative and efficient method. • SETE-HNG has multidirectional ultra-low frequency mechanical vibration monitoring and energy harvesting functions. • A power management circuit is designed to store energy efficiently. [ABSTRACT FROM AUTHOR]

Abstract One significant challenge for electronic devices is that the energy storage devices are unable to provide sufficient energy for continuous and long-time operation, leading to frequent recharging or inconvenient battery replacement. To satisfy the needs of next-generation electronic devices for sustainable working, conspicuous progress has been achieved regarding the development for nanogenerator-based self-charging energy storage devices. Herein, the development of the self-charging energy storage devices is summarized. Focus will be on preparation of nanomaterials for Li-ion batteries and supercapacitors, structural design of the nanogenerator-based self-charging energy storage devices, performance testing, and potential applications. Moreover, the challenges and perspectives regarding self-charging energy storage devices are also discussed.

The water vapor exhaled by the human body can severely accelerate the charge dissipation of a polypropylene (PP)‐based medical mask, thereby reducing the electrostatic adsorption efficiency to cause infection. To solve this problem, a new type of polyvinyl alcohol (PVA)‐based medical mask through electrostatic spinning to replace the PP melt‐blown layer, which has self‐charging and charge retention performance in a high humidity environment is fabricated. The PVA is rich in hydroxyl groups, which can spontaneously form hydrogen bonds with water vapor molecules exhaled by the human body and fix water molecules to increase the triboelectricity. By analyzing the electrical output performance of PVA‐based triboelectric nanogenerator (TENG), it is shown that the short circuit current is ≈26 times larger than that of PP‐based TENG in 95% relative humidity (RH). Moreover, PVA has a strong charge storage capacity and self‐charging performance, as determined by hand touching under a high humidity environment. The static dissipation rate of PVA is 1.4 times lower than that of PP at a 95% RH. In comparison with PP‐based medical masks, PVA‐based medical masks have a high humidity resistance and self‐charging performance and can be easily recharged in situ by hand slapping without taking it off for many times. [ABSTRACT FROM AUTHOR]

Wearable robotic devices often need electrical energy. An interesting idea is to collect mechanical energy during walking and convert it into electrical energy to recharge these devices directly. In this article, we built a light-weight robotic prosthesis (1.3 kg) with the feature of self-charging. During stance phase, the prosthetic ankle joint with damping, is driven by human dynamics. The rotated ankle joint backdrives the motor, and the motor works as a generator according to the electromagnetic induction theory. Five subjects participated in experiments to verify the feasibility and five speeds walking were studied (0.7, 0.9, 1.1, and 1.3 m/s treadmill speeds and one self-selected outdoor walking speed). Experimental results demonstrate that the electrical regenerative energy per step is 1.53 $\pm \;\text{0.29}\,\text{J}$ on average. Meanwhile, an average consumed energy per step of the robotic prosthesis is 4.64 $\pm \;\text{0.15}\;\text{J}$ , which means 33 $\pm \;5\%$ energy can be returned to the active prosthesis (battery, 24 $\,\text{V}$ , 2.6 $\,\text{Ah}$). [ABSTRACT FROM AUTHOR]

Smart wearable electronics that are fabricated on light‐weight fabrics or flexible substrates are considered to be of next‐generation and portable electronic device systems. Ideal wearable and portable applications not only require the device to be integrated into various fiber form factors, but also desire self‐powered system in such a way that the devices can be continuously supplied with power as well as simultaneously save the acquired energy for their portability and sustainability. Nevertheless, most of all self‐powered wearable electronics requiring both the generation of the electricity and storing of the harvested energy, which have been developed so far, have employed externally connected individual energy generation and storage fiber devices using external circuits. In this work, for the first time, a hybrid smart fiber that exhibits a spontaneous energy generation and storage process within a single fiber device that does not need any external electric circuit/connection is introduced. This is achieved through the employment of asymmetry coaxial structure in an electrolyte system of the supercapacitor that creates potential difference upon the creation of the triboelectric charges. This development in the self‐charging technology provides great opportunities to establish a new device platform in fiber/textile‐based electronics. [ABSTRACT FROM AUTHOR]

The extensive utilization of high-end wireless electronic equipment in medical, robotics, satellite, and military communications has created a pressing challenge for real-time electromagnetic interference (EMI) control. Herein, a piezo-powered self-chargeable supercapacitor (PPSC) architecture based on an iron-doped graphitic nitride (Fe-g-C 3 N 4 : FGN) electrode with a solid piezoelectrolyte is devised, which can provide real-time controlled EMI shielding through piezo-powered self-charging voltage (SCV). This PPSC device along with real-time SCV-controlled EMI shielding also integrates additional features like nanoenergy generation and storing capability. The results demonstrate that the PPSC device is capable of exhibiting a piezo-tuned self-charging ability of up to 669.2 mV under 9.47 N of dynamic pressing for 180 s. The SCV electrostatically modifies the PPSC device that causes destructive interference and governs the absorption of electromagnetic radiation (EMR) and controls the absorption-dominated EMI shielding up to 59.2 dB at 500 mV. Additionally, the SCV-led electrification of the PPSC device also controls a unique functional transition from the EMR reflector to the EMR absorber at ∼90 mV. Hence, this strategy of tailored absorption and reflection adjustments of EMR could also potentially contribute toward the advancement of stealth technology for military armaments with externally controlled stealth capabilities.

Pursuing high power density with low platinum catalysts loading is a huge challenge for developing high-performance fuel cells (FCs). Herein, a new super fuel cell (SFC) is proposed with ultrahigh output power via specific electric double-layer capacitance (EDLC) + oxygen reduction reaction (ORR) parallel discharge, which is achieved using the newly prepared catalyst, single-atomic platinum on bimetallic metal-organic framework (MOF)-derived hollow porous carbon nanorods (Pt SA /HPCNR). The Pt SA-1.74 /HPCNR-based SFC has a 3.4-time higher transient specific power density and 13.3-time longer discharge time with unique in situ self-charge and energy storage ability than 20% Pt/C-based FCs. X-ray absorption fine structure, aberration-corrected high-angle annular dark-field scanning transmission electron microscope, and density functional theory calculations demonstrate that the synergistic effect of Pt single-atoms anchored on carbon defects significantly boosts its electron transfer, ORR catalytic activity, durability, and rate performance, realizing rapid " ORR+EDLC" parallel discharge mechanism to overcome the sluggish ORR process of traditional FCs. The promising SFC leads to a new pathway to boost the power density of FCs with extra-low Pt loading., (© 2023 Wiley-VCH GmbH.)

A self-charging hybrid power unit has been developed by integrating a water-evaporation-induced nanogenerator with a flexible nano-patterned supercapacitor. The nanogenerator can harvest environmental thermal energy and mechanical energy through the water evaporation process, and the supercapacitor can be charged simultaneously. The former offers stable electrical power as output, whereas the Ppy-based supercapacitor shows a capacitance of 12.497 mF/cm2 with 96.42% retention after 4,000 cycles. After filling the power unit with water as the fuel, it can be fully charged in about 20 min. The power unit can be flexibly integrated with electronic devices such as sensor nodes and wireless transmitters employing the Internet of Things. This new approach can offer new possibilities in continuous future operation of randomly distributed electronic devices incorporated in the Internet of Things. [ABSTRACT FROM AUTHOR]

This project aims to develop a self-powered, multipurpose system designed to measure an array of biomedical parameters like, SPO2, temperature and pulse rate which serves the need for Telemedicine application. The IOT based biomedical instrument helps in bridging the gap between a doctor and his patient by providing real time diagnosis and treatment through telecommunication technology. This instrument is designed to target individuals who are in fields which go hand in hand with high altitudes and having walking as the only means of transport. Fields like the armed forces, trekking etc. come in this bracket. Piezoelectric sensors are useful for such fields as these require a whole lot of activity but do not usually have active power sources to charge their health monitors. National defence personnel, who have to take care of their bodies in places like Siachen and other difficult terrains, require wearable health devices, now more than ever to continually monitor their health. Hence the design of a self-powered wearable health monitoring device proved to be of critical importance. As the device fulfils telemedicine requirements, it also provides sophisticated health care resources with solutions, allowing the soldier to return to duty and avoid medical evacuation. [ABSTRACT FROM AUTHOR]

This paper presents a new reconfiguration module for asymmetrical multilevel inverters in which the capacitors are used as the dc links to create the levels for staircase waveforms. This configuration of the multilevel converter makes a reduction in dc sources. On the other hand, it is possible to generate 13 levels with lower dc sources. The proposed module of the multilevel inverter generates 13 levels with two unequal dc sources (2VDC and 1VDC). It also involves two chargeable capacitors and 14 semiconductor switches. The capacitors are self-charging without any extra circuit. The lower number of components makes it desirable to be used in wide range of applications. The module is schematized as two back-to-back T-type inverters and some other switches around it. Also, it can be connected as a cascade modular which leads to a modular topology with more voltage levels at higher voltages. The proposed module makes the inherent creation of the negative voltage levels without any additional circuit (such as H-bridge circuit). Nearest level control switching modulation scheme is applied to achieve high-quality sinusoidal output voltage. Simulations are executed in MATLAB/Simulink and a prototype is implemented in the power electronics laboratory in which the simulation and experimental results show a good performance. [ABSTRACT FROM AUTHOR]

Exploring the concept of soft energy unit with improved sustainability and flexibility is critically important for the development of wearable electronics that comes into direct contact with human tissues. Herein, a flexible and self-chargeable sodium-ion full battery was developed by coupling elastic piezo-films with the separator of flexible sodium-ion batteries. This new device achieves excellent flexibility and self-charging performance. It can not only be charged to about 0.65 V under mechanical bending in 150 s or palm patting within 300 s, but also demonstrates interesting self-charging behavior even with quasi-static pressing. In the latter case, the self-charging rate increases with the rising of the applied static forces, which can be ascribed to the sound elasticity of the piezo-film. This work contributes to the development of flexible and self-chargeable electrochemical power devices for soft wearable electronics. A self-chargeable sodium-ion full battery was developed by coupling a flexible sodium-ion battery with an elastic piezo-film, which presents not only excellent flexibility and sound mechanical energy harnessing efficiency, but also remarkable self-charging performance that contributes to the development of next-generation electrochemical power devices for soft wearable electronics. Image 1 • A flexible and self-chargeable full sodium-ion battery (SCSIB) is fabricated. • The elastic piezo-film enables battery sound mechanical energy harnessing efficiency. • The SCSIB demonstrates excellent self-charging performance. • The SCSIB can power several portable electronic devices. [ABSTRACT FROM AUTHOR]

Abstract The rapid advancements of lightweight, customized electronics have imposed a significant challenge on sustainable and maintenance-free micro-energy systems. For the sake of solving the limited power supply and low integration, it seems urgent to develop the flexible energy devices through structure design and performance optimization. Here, a high-efficiency self-charging smart bracelet is proposed by seamlessly combining flexible freestanding triboelectric nanogenerator, power management module with stretchable double-sided micro-supercapacitors. For energy-generating component, the FPCB-based freestanding triboelectric nanogenerator and power management module are adopted with excellent output performance, which obtains peak voltage of 305 V, and maximum power efficiency of 69.3%. Additionally, the double-sided micro-supercapacitors based on CNT-PDMS elastomer are designed to work stably and reliably as the stretchable energy-storing component, the capacitance of which maintains more than 96.87% even under 20% stretching strain. During human normal motions, this smart bracelet could be utilized for scavenging random motion movements and then simultaneously storing in the energy storage device through the high-efficiency power management module to develop a self-powered system for portable devices. As an effective and efficient power supply solution, this proposed self-charging smart bracelet demonstrates admirable potential to power a temperature-humidity meter or pedometer, which owns huge potentials in micro-energy wearable electronics and lays the solid foundation on the smart appliance. Graphical abstract Self-charging smart bracelet is integrated with freestanding triboelectric nanogenerator, power management module and double-sided micro-supercapacitors among the Ecoflex substrate. The smart bracelet could harvest and simultaneously store human motion energy, which could act as wearable power source for self-powered portable electronics. This smart bracelet represents a facile approach and promising improvement to develop stretchable and wearable electronics in the practical applications and next generation self-powered systems. fx1 Highlights • High efficiency self-charging smart bracelet consists of F-TENG, D-MSC and PMM among the same substrate. • With double-sided layout, the stretchable MSC is based on the CNT-PDMS conductive elastomer with electrochemical stability. • Utilizing FPCB technique, the F-TENG and PMM are fabricated together to harvest mechanical energy effectively and efficiently. • The self-charging smart bracelet could scavenge walking motion energy and sustainably drive portable electronics. [ABSTRACT FROM AUTHOR]

With the increase of interest in the application of piezoelectric polyvinylidene fluoride (PVDF) in nanogenerators (NGs), sensors, and microdevices, the most efficient and suitable methods of their synthesis are being pursued. Electrospinning is an effective method to prepare higher content β-phase PVDF nanofiber films without additional high voltage poling or mechanical stretching, and thus, it is considered an economically viable and relatively simple method. This work discusses the parameters affecting the preparation of the desired phase of the PVDF film with a higher electrical output. The design and selection of optimum preparation conditions such as solution concentration, solvents, the molecular weight of PVDF, and others lead to electrical properties and performance enhancement in the NG, sensor, and other applications. Additionally, the effect of the nanoparticle additives that showed efficient improvements in the PVDF films was discussed as well. For instance, additives of BaTiO3, carbon nanotubes, graphene, nanoclays, and others are summarized to show their contributions to the higher piezo response in the electrospun PVDF. The recently reported applications of electrospun PVDF films are also analyzed in this review paper.

This study demonstrates the use of perovskite solar cells for fabrication of self-charging lithium-ion batteries (LIBs). A LiFePO4 (LFP) cathode and Li4Ti5O12 (LTO) anode were used to fabricate a LIB. The surface morphologies of the LiFePO4 and Li4Ti5O12 powders were examined using field emission scanning electron microscopy. The structural properties of the two powders were investigated using X-ray diffraction. The electrochemical properties of the LiFePO4-Li and Li4Ti5O12-Li half cells and of the full cell were investigated. The LiFePO4-Li4Ti5O12 full cell showed an excellent Coulombic efficiency of 99.3% after 100 cycles. CH3NH3PBI3 (MAPbI3) perovskite solar cells (PSCs) were fabricated using a spin coating technique. A single PSC showed a power conversion efficiency of 12.95%. In order to develop a self-charging system for LIBs, four single PSCs connected in series were used as an LFP-LTO battery. The integrated PSC system showed a power conversion efficiency of 12.44%. The PSC-LIB coupled device showed excellent overall self-charging conversion and a storage efficiency of 9.25%.

In present work, a simplistic, efficient and highly durable electroactive and high dielectric BaF 2 nanoparticles (NPs) incorporated polyvinylidene fluoride (PVDF) thin film based Self-Charged Hybrid Photo-Power Cell (HPPC) has been designed which is able to self-charge under visible light illumination. The incorporation of NPs into the PVDF matrix has effectively enhanced the polar β crystallite nucleation (∼96%) and the dielectric value (∼2570) of the PVDF thin film. A composite dye film of TiO 2 NPs, phenosafranine-polyvinyl pyrrolidone in the presence of H 3 PO 4 is acted as the light absorbing and photoelectrons generating part in the HPPC. The photo-electrons are stored in the energy storage part made of the in situ synthesized BaF 2 NPs embedded PVDF thin film. Our HPPC is able to generate a photovoltage ∼1.3 V within 65 s under exposure of visible light (∼110 mW/cm 2 ) with superior energy storage efficiency ∼79%. The device has the ability of storing charge ∼1200 F/m 2 with power density ∼18.7 W/m 2 and charge density ∼1500 C/m 2 . Our light weighted self-charged power bank may be utilized as power supplier in portable electronic appliances. [ABSTRACT FROM AUTHOR]

Flexible power packs combining a flexible photovoltaic part with a wearable all-solid-state supercapacitor as the self-sustaining energy system to power wearable device have attracted great interest due to the increasing demands for green energy and the tendency for multi-functionalization in electronics industry. To meet this energy requirement, we report an asymmetric all-solid-state supercapacitor, then integrate with commercial flexible solar cells to develop a self-sustaining power pack. In view of comfort for wearable electronics, cotton-textile radiation-proof clothes commonly used for pregnant woman cloth (PWC) are selected as the flexible substrate to construct wearable energy storage devices, which have the properties of flexible, green, renewable, breathable and excellent conductivity. Experimental tests demonstrate that the wearable asymmetric supercapacitors with high power density and relatively large energy density, fast charge/discharge capability, light-weight, excellent reliability and flexibility can enable the solar energy captured from the environment to afford a continuous and stable output of electric power and diminish the solar energy fluctuations. The supercapacitor is assembled with the Co–Ni layered double hydroxides (Co-Ni LDH) nanosheets as the positive electrode and the FeOOH as the negative electrode. Furthermore, the fabricated self-sustaining power pack as the energy source can continuously power the press sensor for monitoring the human physiological signals regardless of the sunlight fluctuation, demonstrating its potential usage in future wearable and portable electronic devices. [ABSTRACT FROM AUTHOR]

Self-charging power textile (SCPT) based on energy harvesting and energy storing components for developing wearable electronics exhibits great advantages. However, some problems (stability, weaving methods etc .) in previous work prevent this kind of SCPT for further application and industrial scale-up manufacture. Herein, in this work, we propose a novel SCPT consisting of a fabric triboelectric nanogenerator (FTENG) and a woven supercapacitor (W-SC) for simultaneously harvesting and storing human motion energy. Utilizing traditional woven craft, this one-piece self-power/self-charging power textile can be easily fabricated by alternating the woven wires/threads. For the energy-generating component, we successfully build the contact-separation mode, free-standing mode and other complex patterned TENG on a piece of textile by weaving cotton, carbon and PTFE wires on the handloom. Several key parameters (the diameter of PTFE wire, working frequency, etc .) on the output performance of TENG are systematically studied. For the energy-storing component, utilizing RuO 2 coated carbon fiber and cotton threads, we fabricate W-SC during the weaving process with a stable cotton separator between two fiber electrodes, which possesses extremely high stability for mechanical deformation. Finally, this SCPT is demonstrated to have harvested energy through common daily activities such as running and walking, and simultaneously to have powered the wearable electronics, such as an electric watch. Results show that our newly designed SCPT has great potential for wearable electronics and large scale industrial production. [ABSTRACT FROM AUTHOR]

A simple photovoltaically self-charging energy-storage system (PSESS) has been fabricated as an effective solar energy-storage power cell. The PSESS is capable of the in situ storage of visible light energy in the form of electrical energy. The PSESS is assembled on a photoelectrode (fluorine-doped tin oxide) that contained a dye-sensitized and hole-trapping phenosafranine-polyvinylpyrrolidone film in association with an electroactive and highly dielectric chlorochalcone-polyvinylidene fluoride (PVDF) film, in which photogenerated electrons are stored. Here, chlorochalcone particles act as a catalytic agent for electroactive β crystal nucleation, visible-light emission, and the improved dielectric value of the composite thin films. A proportion of 85 % electroactive β phase nucleation and a high dielectric constant (≈60) are achieved by incorporating 20 mass % chlorochalcone in PVDF. The self-charging capability of the PSESS was verified under a light illumination intensity of 110 mW cm−2. The PSESS was charged up to 0.95 V under light illumination. Moreover, the device wass discharged with a constant current density 1.25 mA g−1 for a long time (≈560 min) after the light was switched off. The photogenerated energy and charge density of the PSESS are approximately 5.25 mWh g−1 and 42 C g−1, respectively. The maximum capacitance attained under the light illumination is approximately 44 F g−1, which is many times greater than two-electrode self-charged photovoltaic cells reported previously. A blue light-emitting diode can be driven by using the PSESSs as a power bank. [ABSTRACT FROM AUTHOR]