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Throughout the world, wind energy is widely distributed as one of the most universal energy sources in nature, containing a gigantic reserve of renewable and green energy. At present, the main way to capture wind energy is to use an electromagnetic generator (EMG), but this technology has many limitations; notably, energy conversion efficiency is relatively low in irregular environments or when there is only a gentle breeze. A triboelectric nanogenerator (TENG), which is based on the coupling effect of triboelectrification and electrostatic induction, has obvious advantages for mechanical energy conversion in some specific situations. This review focuses on wind energy harvesting by TENG. First, the basic principles of TENG and existing devices’ working modes are introduced. Second, the latest research into wind energy-related TENG is summarized from the perspectives of structure design, self-power sensors and systems. Then, the potential for large-scale application and hybridization with other energy harvesting technologies is discussed. Finally, future trends and remaining challenges are anticipated and proposed.

For several decades, the development of potential flexible electronics, such as electronic skin, wearable technology, environmental monitoring systems, and the internet of Things network, has been emphasized. In this context, piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs) are highly regarded due to their simple design, high output performance, and cost-effectiveness. On a smaller scale, self-powered sensor research and development based on piezo-triboelectric hybrid nanogenerators have lately become more popular. When a material in the TENG is a piezoelectric material, these two distinct effects can be coupled. Herein, we developed a multimode hybrid piezo-triboelectric nanogenerator using the CsPbI 3 -PVDF composite. The addition of CsPbI 3 to PVDF significantly enhances its electroactive phase and dielectric property, thereby enhancing its surface charge density. 5 wt % CsPbI 3 incorporation in poly(vinylidene difluoride) (PVDF) results in a high electroactive phase ( F EA ) value of >90%. Moreover, CsPbI 3 -PVDF composite-based PENGs were fabricated in three modes, viz., nanogenerators in contact-separation mode (TECS), single electrode mode (TESE), and sliding mode (TES), and the output performance of all the devices was investigated. The fabricated TECS, TESE, and TES reveal peak output powers of 3.08, 1.29, and 0.15 mW at an external load of 5.6 MΩ. Through analysis of the contact angle measurement and experimental quantification, the hydrophilicity of the composite film has been identified. The hydrophobicity and moisture absorption capacity of CsPbI 3 -PVDF film make it an attractive option for self-powered humidity monitoring. The TENGs effectively powered several low-powered electronic devices with just a few human finger taps. This study offers a high-performance PTENG device that is reliant on ambient humidity, which is a helpful step toward creating a self-powered sensor.

Achieving both high sensitivity and wide detecting range is significant for the applications of triboelectric nanogenerator-based self-powered pressure sensors (TPSs). However, most of the previous designs with high sensitivity usually struggle in a narrow pressure detection range (<30 kPa) while expanding the detection range normally sacrifices the sensitivity. To overcome this well-known obstacle, herein, piezopotential enhanced triboelectric effect realized by a rationally designed PDMS/ZnO NWs hierarchical wrinkle structure was exploited to develop a TPS (PETPS) with both high sensitivity and wide detecting range. In this PETPS design, the piezopotential derived from the deformation of ZnO NWs enhances its tribo-charge transferring ability; meanwhile, the hierarchical structure helps to establish a dynamically self-adjustable contact area. Benefiting from these advantages, the PETPS simultaneously achieves high sensitivity (0.26 nC cm -2 kPa -1 from 1 to 25 kPa, and 0.02 nC cm -2 kPa -1 from 25 to 476 kPa), fast response (46 ms), wide sensing range (1 to 476 kPa), and good stability (over 4000 cycles). In addition, the output charge density that is independent of the speed rate of driven force was adopted as the sensing signal of PETPS to replace the commonly used peak voltage/current values, enabling it more adaptive to accurately detect pressure variation in real applications.

Sliding grating-structured triboelectric nanogenerators (SG-TENGs) can multiply transferred charge, reduce open-circuit voltage, and increase short-circuit current, which have wide application prospects in self-powered systems. However, conventional SG-TENGs have an ultrahigh internal equivalent impedance, which reduces the output voltage and energy under low load resistances (<10 MΩ). The Pulsed SG-TENGs can reduce the equivalent impedance to near zero by introducing a synchronously triggered mechanical switch (STMS), but its limited output time causes the incomplete charge transfer under high load resistances (>1 GΩ). In this paper, a conventional and pulsed hybrid SG-TENG (CPH-SG-TENG) is developed through rational designing STMS with tunable width and output time. The matching relationship among grid electrode width, contactor width of STMS, sliding speed, and load resistance has been studied, which provides a feasible solution for simultaneous realization of high output energy under small load resistances and high output voltage under high load resistances. The impedance matching range is extended from zero to at least 10 GΩ. The output performance of CPH-SG-TENG under low and high load resistances are demonstrated by passive power management circuit and arc discharge, respectively. The general strategy using tunable STMS combines the advantages of conventional and pulsed TENGs, which has broad application prospects in the fields of TENGs and self-powered systems., (© 2024 IOP Publishing Ltd.)

Hydrogel electrolytes are ideal for flexible wearable electronic devices because of their high ionic conductivity, flexibility, and biocompatibility. However, some problems, such as poor mechanical properties, low conductivity, and lack of adhesivity, are encountered in the process of hydrogel preparation and application, which restrict the further development of hydrogel electrolytes. In this study, PVA was used as the first network, and P(AM- co -AMPS) as the second network to prepare a double-network hydrogel electrolyte. Laponite and Na 2 SO 4 were introduced into the hydrogel during hydrogel formation as the nanofiller and salt with the salting-out effect to enhance its mechanical properties. The hydrogel electrolyte with high toughness (1663 kJ·m -3 ), adhesivity (77 kPa), and ionic conductivity (1.7 S·m -1 ) was obtained. In addition, the hydrogel electrolyte also has excellent antifatigue performance. In the 10 consecutive tensile cycles, the tensile strength does not decay. Due to the high adhesivity of the hydrogel electrolyte, a symmetrical all-solid-state supercapacitor was assembled with a tight interface between the hydrogel electrolyte and the AC/CNT composite electrode. The supercapacitor has a high specific capacitance of 186.1 mF·cm -2 at the current density of 1 mA·cm -2 . In addition, the capacitor has good flexibility and can withstand bending at various angles. The hydrogel electrolyte also has excellent strain sensing performance, with an ultrafast tensile response time (0.17 s) and high sensitivity factor (GF = 10.01). Finally, the self-powered sensor system composed of a supercapacitor as the power supply device and hydrogel electrolyte as the sensing part was obtained and applied to human motion monitoring, which provides a potential application in the integrated flexible electronic system.

In this study, a novel piezoelectric energy harvester (PEH) based on the array composite spherical particle chain was constructed and explored in detail through simulation and experimental verification. The power test of the PEH based on array composite particle chains in the self-powered system was realized. Firstly, the model of PEH based on the composite spherical particle chain was constructed to theoretically realize the collection, transformation, and storage of impact energy, and the advantages of a composite particle chain in the field of piezoelectric energy harvesting were verified. Secondly, an experimental system was established to test the performance of the PEH, including the stability of the system under a continuous impact load, the power adjustment under different resistances, and the influence of the number of particle chains on the energy harvesting efficiency. Finally, a self-powered supply system was established with the PEH composed of three composite particle chains to realize the power supply of the microelectronic components. This paper presents a method of collecting impact energy based on particle chain structure, and lays an experimental foundation for the application of a composite particle chain in the field of piezoelectric energy harvesting.

Flexible electronics with great functional characteristics have proved to be a stepping stone in the field of wearable devices. Amongst all, gesture-sensing techniques have been widely studied for human-machine interfaces. In this paper, we propose a self-powered gesture-sensing system attached to the back of the hands, which has the capability of distinguishing hand gestures by measuring the triboelectric nanogenerator output signal. By attaching the sensor on the back of the hand, we can sense the displacement of tendons to detect the gestures. In addition, humidity resistance and durability of the device were tested and validated. Furthermore, we have established a set of rules to define the relationship between gestures and corresponding English letters. Therefore, the proposed sensor can further serve as an electronic sign language translator by converting gestures into words. Finally, we can integrate this system into gloves to enhance the applicability and utility. Overall, we have developed a real-time self-powered back-of-hand sensing system which can recognize various hand gestures. [ABSTRACT FROM AUTHOR]

Harvesting ocean wave energy is a killer application of triboelectric nanogenerator (TENG) for advantages in simple mechanism, high power density and high efficiency at low frequency. Here we report a self-powered intelligent buoy system (SIBS), in which a high-output multilayered TENG is used for water wave energy harvesting. With a power management module, the output voltage can be converted and regulated as a steady DC voltage of 2.5 V for the operations of a microprogrammed control unit (MCU), several micro sensors and a transmitter. With the intelligent monitoring mechanism of the MCU, the harvested energy can be deployed for each sensor with different priority and data transmission cycle, and the SIBS can be at standby and active status by itself at different energy levels. At a wave frequency of 2 Hz, the SIBS can provide an average output power density of 13.2 mW/m2 and realize sustainable and autonomous wireless sensing for acceleration, magnetic intensity and temperature in range of 15 m, with amount of 19 bytes every 30 s. The SIBS has first demonstrated a complete TENG-based micro-energy solution for self-powered intelligent system, including energy harvesting, management, deployment and utilization, with an unattended manner and infinite lifetime. As a significant milestone for the TENG, this work has provided a universal platform for self-powered wireless sensor network nodes and exhibited broad prospects in internet of things, big data, artificial intelligence and blue energy. We propose a self-powered intelligent buoy system (SIBS), including a high-output multilayered TENG for harvesting water wave energy, which can be used for sustainable and autonomous wireless sensing and data transmission. Image 1 • A self-powered intelligent buoy system (SIBS) is proposed, in which a high-output multilayered TENG is used for water wave energy harvesting. • With a power management module, the output voltage can be converted and regulated as a steady DC voltage of 2.5 V for the operations of a microprogrammed control unit (MCU), several micro sensors and a transmitter. • With the intelligent monitoring mechanism of the MCU, the harvested energy can be deployed for each sensor with different priority and data transmission cycle, and the SIBS can be at standby and active status by itself at different energy levels. • This work has provided a universal platform for TENG-based self-powered wireless sensor network nodes and exhibited broad prospects in internet of things, big data, artificial intelligence and blue energy. [ABSTRACT FROM AUTHOR]

In recent years, triboelectric nanogenerators (TENGs) have been increasingly attracting attention owing to the ability for converting multiple mechanical energy into electricity. In this paper, we first propose a multifunctional conductive copper tape-based TENG (CCT-TENG) that is constructed completely using one piece of conductive copper tape. The triboelectric pairs, supporting structure, and conductive electrode were composed using bottom paper, silicone oil, and copper foil, all of which came from one roll of conductive copper tape. The approximate output power density of the CCT-TENG reached $240.1~\mu \text{W}$ /cm2. By spraying the aqueous solution of LiCl onto the surface of the bottom paper, a CCT-TENG incorporating LiCl was fabricated and used as a self-powered active sensor to detect the relative humidity (RH) of the environment. The obtained results revealed that the humidity sensor had good humidity response, response linearity, and reversibility. In addition, the RH was reflected by the brightness of light-emitting diodes (LEDs) that was driven by the humidity sensor. This paper realizes a promising, affordable, and portable integration of power supply systems and sensing systems, which can promote the application of TENG in the field of electronic detection device and environment monitoring. [ABSTRACT FROM AUTHOR]

Abstract Energy harvesters that scavenge biomechanical energy are promising power supply candidates for wearable and implantable electronics. Of the most widely used energy harvesters, piezoelectric generators can generate more electric charge than their triboelectric counterparts with similar device size, thus are more suitable to make compact wearable devices. However, most high-power piezoelectric generators are made from lead zirconate titanate, making them undesirable for wearable applications due to the toxic lead element. In this study, a flexible piezoelectric generator (F-PEG) is fabricated with chemically stable and biocompatible Group-III-nitride (III-N) thin film by a layer-transfer method. The III-N thin-film F-PEG can generate an open-circuit voltage of 50 V, a short-circuit current of 15 µA, and a maximum power of 167 µW at a load resistance of 5 MΩ. Applications of the III-N thin-film F-PEG are demonstrated by directly powering electronics such as light-emitting diodes and electric watches, and by charging commercial capacitors and batteries to operate an optical pulse sensor. Furthermore, the III-N thin-film F-PEG shows good durability and a stable output after being subjected to severe buckling tests of over 30,000 cycles. Graphical abstract III-nitride thin-film-based flexible piezoelectric generator (F-PEG) is developed by transferring the as-grown thin film from silicon to flexible substrate. The lead-free F-PEG can generate a current, voltage and power comparable to conventional PZT-based high-power piezoelectric generators. This highly stable and biocompatible III-nitride thin-film F-PEG can be a promising power supply option for future wearable electronics. fx1 Highlights • III-N flexible piezoelectric generator is fabricated by a layer-transfer method. • Output performance is evaluated both numerically and experimentally. • Energy storage devices charging and simple electronics powering are demonstrated. [ABSTRACT FROM AUTHOR]

Abstract The particulate matter (PM) pollution from vehicle exhaust is one of the main pollution sources in atmospheric environments. Triboelectric particular filter (TPF), coupling triboelectric effect and electrostatic absorption, can effectively controls the emission of nanoscale particulate matter in vehicle. In this work, the captured carbon collected by TPF presents regular graininess particles closed to 100 nm. It is designed as electrode material of the supercapacitor (SC) for energy storage. The SC directly fabricated by the captured carbon without any treatment process displays excellent capacitance performance, which capacitance remains stable during 100,000 continuous cycles. Furthermore, a self-powered system was integrated from triboelectric nanogenerator (TENG) and SCs, which can sustainably power an electronic watch by harvesting biomechanical energy. This work not only presents a novel method to reduce the particular nanoscale particle emission of vehicle but also provides a novel technique to reuse of the captured carbon as energy storage devices to achieve the recycling of waste and the environmental protection simultaneously. Graphical abstract fx1 Highlights • A new method to control the emission of nanoscale particles in vehicles via triboelectric particular filter (TPF) is provided，which can capture micro/nano particles relaying on a coupling effect of triboelectric effect and electrostatic absorption. • The captured carbon collected by TPF presents regular graininess particles closed to 100 nm, which is designed as electrode material of the supercapacitor (SC) for energy storage. The SC directly fabricated by the captured carbon without any treatment process displays excellent capacitance performance, which capacitance remains stable during 100,000 continuous cycles. • A self-powered system was integrated from triboelectric nanogenerator (TENG) and the fabricated SCs, which can power an electronic watch sustainably by harvesting biomechanical energy. • This work provides a novel technique to reuse of the captured carbon as energy storage material to achieve the recycling of waste and the environmental protection simultaneously. [ABSTRACT FROM AUTHOR]

Abstract A great progress has been made in the field of energy harvesting over the past few years to meet the ever-increasing desire of portable, sustainable and renewable energies. Corresponding devices are designed to capture the ambient energies and convert them into usable electrical energy. Piezoelectric nanogenerator, directly scavenging a wide variety of limitless mechanical energy, has been considered as an attractive alternative over traditional rechargeable batteries for providing electrical power to various electric devices. Among piezoelectric materials, poly(vinylidene fluoride) (PVDF) and its copolymers are the most promising candidates for piezoelectric nanogenerators due to their unique electroactive properties, high flexibility, good processability, and long-term stability. However, the piezoresponse generated from their nanogenerators is still low and cannot drive most of electronic devices. Tremendous efforts have been committed to promote the technology and enhance the performance of PVDF-based piezoelectric nanogenerators. This review article highlights recent advances in their performance enhancements with fabrication techniques, piezoelectric materials, conductive and non-conductive fillers. These advanced techniques, new designs and functional materials will be helpful for the increase of piezoelectric crystal structures, alignment of dipoles, charge transfer, etc., consequently improving the output performance of piezoelectric devices. Finally, some perspectives and challenges in this field are also discussed. This comprehensive review will help researchers to learn the piezoelectricity of PVDF-based materials for efficiently converting mechanical energy into electricity, which eventually leads PVDF-based nanogenerators to be a practical power source. Graphical abstract fx1 Highlights • Recent progress of PVDF piezoelectric nanogenerators is summarized. • Advanced fabrication techniques and loading of additives are applied to enhance piezoelectric performance. • The working mechanisms of performance enhancements of nanogenerators are proposed. • An insightful perspective is outlined for the future research. [ABSTRACT FROM AUTHOR]

Thanks to the characteristics of lightweight and high-efficiency in low-frequency, triboelectric nanogenerator (TENG) is considered a highly promising technology to effectively harvest human mechanical energy. However, the low output of wearable TENG significantly limits its application in self-powered wearable electronic systems. Herein, we propose a high-output multilayer-structured triboelectric nanogenerator (HM-TENG) fabricated by nylon/ L -cystine composite nanofiber film (NCNF), which can efficiently harvest various human bio-mechanical energy. Based on the excellent positive triboelectric performance of L -cystine and the corresponding preparation process research, the fabricated TENG by NCNF with 8 w% L -cystine achieves several times the output performance of TENG with pure nylon nanofiber. Besides, the fabricated HM-TENG obtain a high power density of 11.52 W/m2, which is 5–500 folds higher than previous related research work. Importantly, relied on the designed power management circuit and the installation of a foot mounted HM-TENG, various self-powered wearable electronic devices constructed by harvesting human bio-mechanical energy have been successfully demonstrated. Our research not only provides a novel method for developing high-output TENG but also offers a important solution for the design of self-powered electronic devices. [Display omitted] • It is found that L -cystine has better positive triboelectric performance than nylon through software simulation. • Fabricated by NCNF with 8 w% L -cystine, TENG achieves several times output performance of TENG with pure nylon nanofiber. • The power density of HM-TENG increased to 11.52 W/m−2, which is 1–2 orders of magnitude higher than previous similar studies. • HM-TENG with PMC can provides energy for sustainable operation of wearable electronics by harvesting bio-mechanical energy. [ABSTRACT FROM AUTHOR]

For develop high-performance elastic-materials-based triboelectric materials, a simple and effective gradient-constructing process of triboelectric charge for fabricating elastic-polydimethylsiloxane-based materials with the high surface charge density, thereby enabling high power density, high responsivity and low manufacturing cost elastic-materials-based TENGs. [Display omitted] • Using gradient construction process prepares high performance elastic polydimethylsiloxane-based triboelectric material. • Output power density of gradient-constructed materials enhances than the pure structure and uniform-constructing. • EMB-TENGs exhibiting a high-sensitive and the coefficient of determination within the pressure range of 10 N to 40 N. • Developed a self-powered acquisition and calculation system in real-time. Elastic-materials-based triboelectric nanogenerators (EMB-TENGs) play a significant role in advancing the high-entropy energy harvesting and self-powered system, which increasing the power output is one of the most important fields for practical application. Here, we develop a polydimethylsiloxane-based triboelectric materials with high charge density by gradient-constructing strategy. Based on the materials of EMB-TENG is capable of outputting a power density of 2.48 W⋅m−3 under an external load resistance of 80 MΩ, which is increasing by 39.94 % and 23.19 % compared with pure and uniform-constructing, respectively. The coefficient of determination (R2) reaching up to 0.998 in the pressure range of 10 N to 40 N, and 0.943 in the pressure range of 40 N to 60 N. Additionally, resulting in the development of a self-powered sensing system and gaining the ability of real-time acquisition and calculation. This work has a comprising prospect of application in many areas including the development of novel triboelectric materials, theoretical research, energy harvesting and sensing. [ABSTRACT FROM AUTHOR]

The development of an accurate, selective, sensitive, and quantitative monitoring method for copper ion (Cu2+) in water and soil is crucial for addressing environmental pollution. Herein, a photocatalytic fuel cell self-powered sensor (PFC-SPS) platform was proposed by carbon-rich carbon nitride photoanode for Cu2+ determination. Carbon-rich carbon nitride is formed by replacing nitrogen atoms of tertiary nitrogen with carbon generated through the thermal decomposition of biomass chitosan. The carbon-rich structure enhances the π delocalization in the carbon nitride skeleton, improving the optical absorption and accelerating the transmission of charge, endowing the photoanode with high and stable output signal. The formed Cu2+-aptamer complex increases the surface resistance of electrode, hindering the catalytic reaction of H 2 O 2 oxidation and leading to the decrease in the output power density signal. This PFC-SPS platform detected Cu2+ with a wide range of 1.0 ∼ 1.5 × 103 nM, a low limit of 0.40 nM, excellent selectivity, stability and accuracy for real river water and agricultural soil samples. It is expected that the platform can achieve low-cost and portable monitoring by a digital multimeter, and this work also proposes a strategy for detecting heavy metal ions based on the synergism of a photocatalytic fuel and self-powered platform. [Display omitted] • mtCN-x has a large π delocalization owing to carbon-rich structure. • Carbon self-doping g-C 3 N 4 enhances the light absorption, showing high PEC property. • A PFC-SPS platform detected Cu2+ with high sensitivity and selectivity. • The platform can achieve low-cost and portable monitoring by a multimeter. [ABSTRACT FROM AUTHOR]

• Self-polling effect by metal–organic frameworks was suggested to change the polarity of organics. • The performance of the nanogenerator was enhanced by the self-polling process. • Proof of concept for a self-powered signal trigger for a smart home control system was demonstrated. Metal-organic frameworks (MOFs) exhibit various unique properties, but these properties have not been fully utilized for the performance enhancement of triboelectric nanogenerator (TENG). The MOFs with MIL-101(Cr) structure is a nanomaterial designed for extremely large pore structures than conventional MOF structures to absorb and desorb various solvents, which induces a new phenomenon, self-polling effect (SPE) in the organic materials. We verified and suggested the SPE mechanism of the N, N-dimethylformamide (DMF) solvent by the MIL-101(Cr) structured MOFs in the polyvinylidene fluoride (PVDF) nanofibers. Because of the SPE, the MOFs-based composite NFs showed enhanced TENG output performances by additionally induced β -phase in the PVDF NFs even after the electrospinning process. The composite PVDF NFs with optimal MOF content of 0.8 wt% showed an output power density of 568.8 µW/cm2, which is larger by 8.96 times compared to the pure PVDF NFs. After the SPE process, the output power density increased to 871.2 µW/cm2, which is 13.7 times larger than that of pure PVDF NFs. Different from the pure PVDF NFs, the MOFs-based composite PVDF NFs showed improved output powers after the SPE process regardless of MOF contents. Based on excellent performance, the TENG with the MOFs-based composite PVDF NFs was sufficiently utilized as a self-powered triggering sensor for smart home devices that can wirelessly operate various electronic devices. [ABSTRACT FROM AUTHOR]

The development of polymer-based devices has attracted much attention due to their miniaturization, flexibility, lightweight and sustainable power sources with high efficiency in the field of wearable/portable electronics, and energy system. In this work, we proposed a polyvinylidene fluoride (PVDF)-based composite matrix for both energy harvesting and energy storage applications. The physicochemical characterizations, such as X-ray diffraction, laser Raman, and field-emission scanning electron microscopy (FE-SEM) analyses, were performed for the electrospun PVDF/sodium niobate and PVDF/reduced graphene oxide composite film. The electrospun PVDF/sodium niobate nanofibrous mat has been utilized for the energy harvester which shows an open circuit voltage of 40 V (peak to peak) at an applied compressive force of 40 N. The PVDF/reduced graphene oxide composite film acts as the electrode for the symmetric supercapacitor (SSC) device fabrication and investigated for their supercapacitive properties. Finally, the self-charging system has been assembled using PVDF/sodium niobate (energy harvester), and PVDF/reduced graphene oxide SSC (energy storage) and the self-charging capability is investigated. The proposed self-charging system can create a pathway for the all-polymer based composite high-performance self-charging system.

Abstract We present a self-powered, wireless radio frequency (RF) transmitter based on the combination of triboelectric nanogenerator (TENG) and piezoelectric element, which can send coded signal remotely to a receiver when the sensor is triggered. The piezoelectric element is connected to an energy management module (EMM) which supplies regulated power suitable for powering the RF module; the triboelectric nanogenerators (TENGs) act as sensors, which control the code being transmitted by the RF module. In addition, a switch is embedded in TENG to control the power supply from EMM to the RF module; only at the moment of TENG being pressed, the power stored in EMM (ultimately from the piezoelectric element) is supplied to the RF module, and the intended RF signal is transmitted. The RF signal is then received by the receiver and the transmitted code is deciphered and then visualised by a Labview program on PC. Four TENGs are used as sensing elements of mechanical pressing, and each triggers a different command to be transmitted. It is believed that, with such novel combination of the piezoelectric element for powering and TENG for sensing, this is a novel application of TENG and piezoelectric element to transmit coded RF signal with regulated power supply suitable for many modern electronics. The designed self-powered RF transmission system and the general system structure have potentially widespread applications in wireless communication and sensing, especially in applications where power or electricity is disrupted/unavailable, such as disaster rescue/relief, e.g. entrapment in buildings and natural environments due to lift malfunction, earthquake, landslide, debris flow, and blizzards, etc. Graphical abstract The designed self-powered and wireless radio frequency (RF) transmission device is based on the combination of triboelectric nanogenerator (TENG) and piezoelectric element, capable of sending coded signal up to 100 m outdoor and 28 m indoor once triggered. It provides a general system structure with widespread applications such as monitoring health states of buildings and infrastructure, and disaster rescue/relief. fx1 Highlights • A self-powered and wireless RF transmission device is designed. • The device is based on the piezo element for powering and TENG for sensing. • Coded signals from the designed device can be received and deciphered by a receiver. • The designed device has been shown to work in simulated disaster rescue scenarios. [ABSTRACT FROM AUTHOR]

Abstract Reusing waste materials to create energy harvester will not just reduce the environmental pollution, but also generate renewable electricity by scavenging environmental energy to power wireless electronic devices, which will make our life more environmental friendly. In this study, we first turn waste milk carton into fully packaged arc-shaped triboelectric nanogenerator (AS-TENG) which can scavenge both wind and water flow energy for long-term wireless environmental monitoring. In general, the milk carton is laminated (from inside out) with a layer of polyethylene (PE), a layer of aluminum (Al) foil and a pulp layer. Such laminated material is suitable as the electrical unit of the AS-TENG. The arc-shaped design of AS-TENG is implemented to disrupt the flow, leading to vortex induced vibration, and thus contact electrification of the AS-TENG results in power generation. By optimizing the structural parameters systematically, the AS-TENG achieves an instantaneous peak voltage of 600 V, and a current of 40 μA. Moreover, a self-powered wireless environmental monitoring system using AS-TENG as power supply is developed for in-situ real time water quality (pH value) monitoring and landslide early warning in natural environment. This study provides solid progress toward the practical applications of TENGs in environmental monitoring. Graphical abstracts Reusing waste materials to create energy harvester will not just reduce the environmental pollution, but also generate renewable electricity by scavenging environmental energy to power wireless electronic devices. In this study, an environmental friendly, multifunctional and fully packaged arc-shaped triboelectric nanogenerator (AS-TENG) by reusing waste milk carton is developed and capable of scavenging both wind and water flow energy efficiently. Moreover, a highly-integrated data acquisition, processing and wireless transmission monitoring system based on AS-TENG is established for real time and long-term water quality (pH value) monitoring and landslide early warning in natural environment. fx1 Highlights • The first environmental friendly triboelectric nanogenerator (TENG) reuses waste milk cartons for energy harvesting. • The arc-shaped triboelectric nanogenerator (AS-TENG) with novel design is multifunctional and waterproof. • The self-powered sensor system was developed using AS-TENG for long-term water quality monitoring and landslide warning. [ABSTRACT FROM AUTHOR]

Abstract Pathogenic bacteria that give rise to infection have posed major health concerns over the past several decades. In this paper, we propose a self-powered active disinfection system controlled by human motions. The system is mainly composed of a multilayered triboelectric nanogenerator (m-TENG) for the harvesting of biomechanical energy and conductive fabrics as electrodes for the wearable disinfection system. The working principle of the system is based on hybrid effects of H 2 O 2 production and electroporation, which provide good disinfection performance toward gram-negative Escherichia coli (E. coli) and gram-positive Staphylococcus aureus (S. aureus). In addition, we also demonstrate that the presence of gold-coated tellurium nanowires (Au-Te NWs) on the fabrics increased the strength of local electric field and enhanced the system's disinfection performance. With the help of Au-Te NWs, the disinfection activities of the system reach values of more than 87% and 96% against S. aureus and E. coli , respectively, when the m-TENG was operated at a frequency of 1 Hz for 60 min. Furthermore, the disinfection activity can be strengthened by increasing the operation frequency or electric output of the m-TENG. Alternatively, the generated electricity can be stored in a capacitor to achieve rapid disinfection via an instantaneous discharging process. Because of the fiber-based structure in the disinfection device and the shoe-embedded design of the m-TENG, our proposed self-powered active disinfection system can be easily integrated into commercial textiles to fabricate smart clothes to combat pathogenic bacteria. Graphical abstract The concept of self-powered active disinfection system for clothing is proposed. A m-TENG is embedded in shoe soles to harvest mechanical energy from human motions. CFFs modified with Au-Te nanowires function as electrodes of the disinfection device. The electric output from the m-TENG enables simultaneous disinfection of bacteria inside the CFFs through the hybrid effects of H 2 O 2 production and electroporation. fx1 Highlights • Carbon fiber fabrics modified with Au-Te nanowires were fabricated. • The hybrid effects of hydrogen peroxide generation and electroporation were realized for sterilization. • The concept of the self-powered antibacterial system is potential to develop smart clothes. [ABSTRACT FROM AUTHOR]

Flexible electronics based on the paper have attracted significant attention. A paper-based triboelectric nanogenerator (TENG) consisting of commercial and low-cost materials, e.g., printer paper, polytetrafluoroethylene tape, and conductive ink, was proposed in this study. This TENG unit can directly illuminate 24 blue commercial LEDs. Furthermore, compound paper-based TENGs were developed and a considerable enhancement of the electrical output performance was thereby realized. These compound TENGs can also serve as a height sensor. [ABSTRACT FROM AUTHOR]

Piezoelectric 0.72 Pb(Zr 0.47 Ti 0.53 )O 3 -0.28 Pb[(Zn 0.45 Ni 0.55 ) 1/3 Nb 2/3 ]O 3 + 0.5 mol% CuO (PNNC) particles were made for use in a composite of flexible energy harvester (FEH) that can convert sustainable mechanical deformation into electrical energy. The PNNC particles with a high transduction coefficient ( d 33  ×  g 33 ) were mixed with polydimethylsiloxane (PDMS) matrix to produce the FEH. The FEH generated maximum output voltage of 55.24 V and current density of 2.76 μA/cm 2 (power density: 554 μW/cm 3 , 3.2 mW) at the resonance frequency of 11 Hz. The energy conversion efficiency of about 20.7% has been achieved. The developed energy harvester is demonstrated in the self-powered wireless sensor node application in which the FEH spontaneously generated stable power under continuous mechanical stress. [ABSTRACT FROM AUTHOR]

Paper-based triboelectric nanogenerators (TENGs) represent an affordable, green, and eco-friendly energy harvesting methodology. In this work, we propose a novel X-shaped paper TENG (XP-TENG) formed from a ballpoint ink layer coated by painting with a commercial brush pen. The paper and Teflon tape serve as the triboelectric pairs, with the paper serving as the supporting component. Moreover, the XP-TENG is capable of providing two working patterns that can yield an expanded scope of practical applications. A stacked XP-TENG was proposed for increasing the output performance and harvesting the mechanical energy generated by motion of the human body. This staked XP-TENG can directly light up 101 blue high-power LEDs with working voltage of 3.4 V. The fabricated XP-TENG can be used for harvesting mechanical energy from human walking. [ABSTRACT FROM AUTHOR]

Electrolysis of water is utilized as an environment friendly approach for production of hydrogen (H 2 ). An external power supply for driving the oxidation or reduction reactions of H 2 O molecules is mandatory for electrolysis. Harvesting energy from our living environment for electrolytic water splitting is a cost-effective technology for mass production of H 2 . Here, a coaxial rotatory freestanding triboelectric nanogenerator (CRF-TENG) wind energy harvester was demonstrated, in which the electrospinning PVDF nanofibrous membrane served as triboelectric material. And then a fully self-powered water splitting system for hydrogen production was presented based on the CRF-TENG. By scavenging ambient wind energy, the generated electricity is used for water splitting to produce H 2 , instead of the external power source. The amounts of H 2 were measured by a gas circulation system and gas chromatograph and the H 2 evolution rates were calculated. When the wind speed is 10 m/s, the hydrogen generation rate reaches 6.9685 μL/min in the 1 M KOH solution, suggesting an easy scale-up and efficient route for converting ambient mechanical energy into hydrogen energy. Such self-powered water splitting system opens up a new road to more energy applications. [ABSTRACT FROM AUTHOR]

A novel self-powered system was constructed to in situ remove nitrate and Cr(VI) from synthetic groundwater and achieve river sediment remediation simultaneously. The sediment organic matter in an anodic chamber was used as a carbon source to provide self-powered energy to reduce the cathode’s contaminants. With the acceptance of protons and electrons, nitrate and Cr(VI) were transformed into nitrite and Cr(III), respectively. In a 72 h test with both nitrate and Cr(VI) present, nitrate was removed at a rate of 70.96 mg/m3·h and Cr(VI) at a rate of 8.95 mg/m3·h. When a phosphate buffer was used in the test, their removal rates were changed to 140.83 mg/m3·h and 8.33 mg/m3·h, respectively. The results showed that the self-powered system could achieve the simultaneous reduction of nitrate and Cr(VI), although the presence of Cr(VI) hindered nitrate reduction. This system could realize simultaneous in situ groundwater and sediment remediation, with no need for additional energy or materials. [ABSTRACT FROM AUTHOR]

Blue energy harvested from the ocean is an important and promising renewable energy for the sustainable development of society. Triboelectric nanogenerators (TENGs) are considered one of the most promising approaches for harvesting blue energy. In this work, a liquid-solid-contact triboelectric nanogenerator (LS TENG) is fabricated to enhance the friction and magnify energy output by 48.7 times, when compared with the solid-solid-contact TENG with the same area. The buoy-like LS TENG can harvest energy from different types of low-frequency vibration (including up-down, shaking, and rotation movements). Moreover, the outputs of the LS TENGs network can reach 290 µA, 16 725 nC, and 300 V, and the LS TENGs network can directly power hundreds of LEDs and drive a radio frequency emitter to form a selfpowered wireless save our souls (SOS) system for ocean emergencies. This work renders an innovative and effective approach toward large-scale blue energy harvesting and applications. [ABSTRACT FROM AUTHOR]

Abstract: Blue energy harvested from the ocean is an important and promising renewable energy for the sustainable development of society. Triboelectric nanogenerators (TENGs) are considered one of the most promising approaches for harvesting blue energy. In this work, a liquid–solid‐contact triboelectric nanogenerator (LS TENG) is fabricated to enhance the friction and magnify energy output by 48.7 times, when compared with the solid–solid‐contact TENG with the same area. The buoy‐like LS TENG can harvest energy from different types of low‐frequency vibration (including up–down, shaking, and rotation movements). Moreover, the outputs of the LS TENGs network can reach 290 µA, 16 725 nC, and 300 V, and the LS TENGs network can directly power hundreds of LEDs and drive a radio frequency emitter to form a self‐powered wireless save our souls (SOS) system for ocean emergencies. This work renders an innovative and effective approach toward large‐scale blue energy harvesting and applications. [ABSTRACT FROM AUTHOR]

Electricity generation from the interaction between water and carbon materials is a new approach in the pursuit of high-efficiency energy conversion. Here, we report that a water droplet dropping onto a piece of porous carbon film can spontaneously generate electricity under ambient conditions. Twelve 5-μL water droplets can generate a voltage up to 5.2 V and illuminate a liquid crystal display. The voltage can be controlled by modulating the direction of the droplet infiltration, the zeta potential of the porous carbon, and the ion concentration. The results demonstrate that a hydrophilic porous carbon film with water droplets may function as a cost-effective electricity generator for harvesting energy from natural resources. [ABSTRACT FROM AUTHOR]

We present a simple implementation of a thermal energy harvesting circuit with the maximum power point tracking (MPPT) control for self-powered miniature-sized sensor nodes. Complex start-up circuitry and direct current to direct current (DC-DC) boost converters are not required, because the output voltage of targeted thermoelectric generator (TEG) devices is high enough to drive the load applications directly. The circuit operates in the active/asleep mode to overcome the power mismatch between TEG devices and load applications. The proposed circuit was implemented using a 0.35-μm complementary metal-oxide semiconductor (CMOS) process. Experimental results confirmed correct circuit operation and demonstrated the performance of the MPPT scheme. The circuit achieved a peak power efficiency of 95.5% and an MPPT accuracy of higher than 99%. [ABSTRACT FROM AUTHOR]

• Propose a combined design method of RF energy and management. • Determine the simulation boundaries of the RF energy harvester. • Design a highly integrated and high performance self-powered wireless sensor node. • Power a wireless sensor node using radio frequency energy at a distance of 13.5 m. Environmental energy-harvesting technologies, such as solar, vibration, and radio frequency (RF) energies, can effectively increase the lifespan of wireless sensor nodes while reducing their size, weight, and cost. Generally, RF energy harvester design methods are based on ideal energy sources and resistive loads, whereas real RF energy conversion and management are extremely complex and cannot be verified using conventional design methods. In this study, an RF energy harvesting and management combined design method is proposed to attain the requisite output parameters of an RF energy harvester to enable load operation during the design phase. Based on the proposed method, a highly integrated high-performance RF energy-harvesting wireless sensor node (RF-EH WSN) is constructed. The experimental results indicate that the input energies for both the simulation and measurements are equal and consistent (-10 dBm) for identical expected output voltages and energies. The proposed WSN can achieve self-powered operation at a distance of 13.5 m from a 27 dBm RF energy source. [ABSTRACT FROM AUTHOR]

Indoor air quality plays a critical role in maintaining human health and well-being. In this study, a novel self-powered and high-efficiency negative air ion (NAI) generator in pipeline is proposed for air purification in the ventilation system. The self-power is achieved by utilizing a novel device of wind energy triboelectric nanogenerator (WE-TENG) to efficiently harvest wind energy in the pipeline. The present WE-TENG of investigation can reach a high rotation speed of 1300 rpm at 5.5 m/s in the pipe with a pressure drop of 175 Pa. After the power management circuit, the self-powered NAI generator is capable to drive 21 carbon-fiber electrodes to generate NAIs, with a generation rate of 23.14 μC/s. The self-powered NAI generator efficiently generates a high volume of NAIs in the pipeline, harnessing the air-purifying properties of NAIs, thereby making a significant impact on the practical application of self-powered indoor air purification systems based on TENG. [Display omitted] • A self-powered negative air ion generator is proposed for the ventilation system with a novel wind energy TENG. • The output characteristics of four types of power management circuits driven by TENG are investigated. • The generation of negative air ions is promoted by enhancing the electric field strength. • The performance of the power management circuit to drive NAI generator is quantified. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3) is an essential feedstock for modern industry and agriculture, as well as a promising energy carrier owing to its high energy density (4.3 kWh kg–1) and storage security. The electrocatalytic nitrate reduction reaction to ammonia (NRA) is a promising alternative route for convenient and distributed NH 3 synthesis coupled with clean energy, and is attracting widespread attention. Building a coupled system for NH 3 production between NRA and clean energy capture is an exciting direction for future distributed energy utilization and conversion. Herein, a lightweight triboelectric nanogenerators (TENGs) with ultra-low start-up wind speed (3.0 m s–1) is coupled to NRA system loaded with polycrystalline copper, enabling energy harvesting in a wide wind speed band for the efficient NH 3 production. An adaptation strategy for capacitor embedded in the energy conversion process is proposed to further enhance the efficiency of coupled system, achieving a high NH 3 yield of 11.48 μg cm−2 h–1 with the high catalytic activity of polycrystalline copper on cathode. This work opens up a coupled electrocatalysis and natural energy capture system for the conversion of NO 3 – to NH 3 , and provides an idea for the renewable energy conversion and nitrogen cycle remediation. [Display omitted] ● Density-filling strategies and 3D printing technologies are adopted to manufacture lightweight TENGs to harvest wind energy. ● The efficient polycrystalline copper catalysts are prepared by electrodeposition strategy. ● A self-powered nitrate reduction to ammonia system is constructed by TENGs and efficient polycrystalline copper catalysts. ● Optimizing power management circuit is employed to maximize ammonia yields. [ABSTRACT FROM AUTHOR]

With the rapidly increasing number of older people in our societies, fall detection is becoming more important: Older adults may fall at home when they are alone and they may not be found in time for them to get help. In addition, a fall itself can cause serious injuries such as lacerations, fractures and hematomas. Although many previous studies have been reported on various fall detection technologies based on wearable sensors, the inconvenience of wearing them is problematic. Vision or ambient based methods may be alternatives, but high cost and complex installation process limit applicable areas. We propose a cost-effective, ambient-based fall detection system based on a pressure sensing triboelectric nanogenerator (TENG) array. Apart from simple observation of output signal waveforms according to different actions, key technologies, including appropriate filtering and distinguishing between falls and daily activities, are demonstrated with data acquisition from 48 daily activities and 48 falls by eight participants. The proposed system achieves a classification accuracy of 95.75% in identifying actual falls. Due to its low cost, easy installation and notable accuracy, the proposed system can be immediately applied to smart homes and smart hospitals to prevent additional injuries caused by falls. [ABSTRACT FROM AUTHOR]

Water oxidation or oxygen evolution reaction (OER) electrocatalysis got much attention in the last few years because of its prime role in water splitting, rechargeable metal-air batteries and fuel cells. Therefore, the development of efficient, abundant and economical catalysts for water oxidation reaction is one of the main subjects of present study in renewable energies. This review article summarizes the very recent efforts in the field of OER electrocatalysis along with the faced challenges. The solutions to these challenges also outline with appropriate examples of scientific literatures. Significantly, the present review will provide the standards to evaluate the activity and stability for heterogeneous OER catalysts. It will clearly summarize the future directions and applications, especially the combination of sustainable energy utilization (like triboelectric nanogenerator) with water splitting. The providing study will help to explore and develop better catalysts and units for practical applications and will offer basic understanding of OER process along with the standard parameters to evaluate the performance. [ABSTRACT FROM AUTHOR]

We propose a novel electrokinetic generator driven by the capillary force. By coupling the capillary with water evaporation, the generator can output power as long as water evaporation exists, thus it can harvest environment energies from waste heat, wind power to solar energy. Experimental results show that a capillary driven electrokinetic generator, with evaporation area of 4.9 cm 2 and fluidic channel area of 2 mm 2 , can output maximum electrical voltage of ∼40 mV and current of 9.6 μA. The voltage and current can both be greatly enhanced by reducing the area of fluidic channel, approaching maximum power of 0.22 mW according to the theoretical calculations. In addition, a live-tree driven electrokinetic generator with an output electrical power of 2.7 μW is demonstrated. These results show that the capillary driven electrokinetic generator is of promising potential in self-powered systems. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator (TENG) has the output characteristics of high voltage but low current/charge-transfer, making its low efficiency in powering most of electronics. To address this problem, power management circuits consisting of coupled inductors or transformers are usually employed. Here we report an inductor-free, auto-power-management design based on automatic switches between serial-connected and parallel-connected capacitors in a rationally designed manner, so that the output voltage can be lowered and the output charge is enhanced in proportion. In conjunction to theoretical analysis, a TENG along with proof-of-concept power-management units as automatically driven by the triggering motion for TENG is fabricated, which improves the rate for charging a supercapacitor by 5 times. Compared to previous work, this power-management design shows advantages of capability for harvesting low power/frequency scale energy, high scalability, and light weight, which paves a new approach for achieving high-efficient portable TENG-based self-powered system. [ABSTRACT FROM AUTHOR]

Developing self-powered smart wireless sensor networks by harvesting industrial environmental weak vibration energy remains a challenge and an impending need for enabling the widespread rollout of the industrial internet of things (IIoT). This work reports a self-powered wireless temperature and vibration monitoring system (WTVMS) based on a vibrational triboelectric nanogenerator (V-TENG) and a piezoelectric nanogenerator (PENG) for weak vibration energy collection and information sensing. Therein, the V-TENG can scavenge weak vibration energy down to 80 μm to power the system through a power management module, while the PENG is able to supply the frequency signal to the system by a comparison circuit. In an industrial vibration environment where the vibration frequency and amplitude are 20 Hz and 100 μm, respectively, the WTVMS can upload temperature and frequency information on the equipment to the cloud in combination with the narrowband IoT technology to realize real-time information monitoring. Furthermore, the WTVMS can work continuously for more than 2 months, during which the V-TENG can operate up to 100 million cycles, achieving ultrahigh stability and durability. By integrating weak vibration energy harvesting and active sensing technology, the WTVMS can be used for real-time online monitoring and early fault diagnosis of vibration equipment, which has great application prospects in industrial production, machinery manufacturing, traffic transportation, and intelligent IIoT.

Overspeed information monitoring and collecting becomes increasingly important with the rapid development of intelligent transportation, but current overspeed monitoring technologies are constrained by traditional power-supply for large-scale use. Herein, we proposed a self-powered overspeed wake-up alarm system (SOWAS) based on triboelectric nanogenerators. The SOWAS consists of an energy harvesting triboelectric nanogenerator (E-TENG), an energy management module (EMM), an overspeed sensing triboelectric nanogenerator (S-TENG), a power-switch module (PSM) and a wireless transceiver module (WTM). The E-TENG and EMM are used for mechanical energy harvesting, management, and powering for the SOWAS, while the S-TENG, PSM and WTM are employed for active overspeed monitoring and alarm signals transmitting. When the vehicle speed exceeds the setting threshold, the PSM will be activated, and the WTM will send alarm signals with the harvested energy. The response characteristics dependence of the SOWAS on various working parameters were investigated in detail. The developed SOWAS could work sustainably in unattended traffic environment without external power supply for autonomous overspeed monitoring and alarming. Meanwhile, intelligent monitoring of overspeed and improved energy utilization were achieved. This work has enormous potentials and promising prospects for TENG in intelligent transportation, Internet of Vehicles and autonomous driving. [Display omitted] • A self-powered overspeed wake-up alarm system (SOWAS) based on TENGs is developed. • The SOWAS enables sustainable self-powered overspeed monitoring and alarm by harvesting the mechanical energy from traffic system. • Intelligent overspeed monitoring is achieved by the designed wake-up circuit and the efficient use of energy. [ABSTRACT FROM AUTHOR]

Incorporation of inorganic materials into a polymer matrix has drawn significant interest, as the process can improve the mechanical and triboelectric properties of composite products. However, well dispersion and long-term stability of the developed composites remain a challenge. In this paper, we propose a novel Nafion-functionalized barium titanate nanoparticles (BaTiO 3 NPs)/polyvinylidene fluoride (PVDF) composite nanofibers based high-performance triboelectric nanogenerator (NBP-TENG), which can serve as a self-powered human-machine interface for a smart control system. Specifically, our method of introducing Nafion provides an excellent dispersion of BaTiO 3 into the PVDF matrix. As a result, a highly stable dispersion is maintained for almost 6 months without any noticeable precipitation or agglomeration. Consequently, the excellent dispersion enhances the effective stress transfer at the interface between the BaTiO 3 and PVDF, resulting in the remarkably improved negative surface potential in the BaTiO 3 /PVDF homogeneous composite nanofibers. The NBP-TENG allows the generation of high output voltage, current density, and power density of 307 V, 1.8 µA/cm2, and 1.12 mW/cm2, respectively, which are enhanced by ∼ 6.3, 7.1, and 3.7 times, respectively, compared to pristine PVDF nanofibers. The NBP-TENG is capable of powering dozens of commercial LEDs connected in series by manual tapping and demonstrates stable output performance even after 10,000 cycles of repeated contact separation. Moreover, the NBP-TENG can be utilized as a self-powered human-machine interactive interface for smart street and home control systems, with the advantages of promising reliability, cost-effectiveness, energy efficiency, and practicality. [Display omitted] • A Nafion-functionalized BaTiO 3 / PVDF composite nanofibers based TENG is designed to effectively harvest mechanical energy. • Introducing Nafion enables excellent dispersion and long-term stability of BaTiO 3 into the PVDF matrix. • Self-powered smart street and home control systems are demonstrated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zeolitic imidazolate framework nanocrystal decorated polyacrylonitrile nanofiber. • Triboelectric nanogenerator for self-powered visible light communication system. • Nanofibers provide a higher effective surface area for contact-electrification. • Remarkable electrical power output from nanofiber-based triboelectric nanogenerator. • Nanogenerator for the wireless control of home appliances and text messaging systems. We propose a zeolitic imidazolate framework (ZIF-8) nanocrystal decorated electrospun polyacrylonitrile (PAN) nanofiber as an efficient triboelectric positive material for the high-performance triboelectric nanogenerator (TENG) and demonstrate a self-powered visible light communication (VLC) system for wireless human-machine interactions. The PAN@ZIF-8 nanofibers provide a higher effective contact surface area that can contribute to the improvement of the total amount of generated charges. This can enable the energy harvesting performance of the PAN@ZIF-8 based TENG (PZ-TENG) to be increased more than 3 times compared to their individual PAN nanofibers and ZIF-8 crystal based TENG devices. Furthermore, we develop a PZ-TENG driven self-powered VLC system and utilize it for the wireless control of home appliances and text messaging systems. 3-bit binary codes are designed with two different mechanical activities (clicking '0′ and flapping '1′) for secure and wireless control of the home appliances (Fan, Humidifier, Bell, and Lamp) and to send a text message "HI DGU" on a mobile phone. The designed self-powered VLC system with advanced coding concepts can further enable remote personal identification, security defense, and smart home authentication and monitoring applications. [ABSTRACT FROM AUTHOR]

Bridge health monitoring system can play a role in bridge safety early warning, fatigue diagnosis, and life prediction. However, traditional bridge health monitoring system relies on manpower or battery power supply, which challenges the real-time effectiveness of health monitoring sensors. Herein, we proposed a self-powered bridge health monitoring system based on the elastic origami structure triboelectric nanogenerator (EO-TENG) array. In detail, the self-powered bridge health monitoring system contains the self-powered bridge health data acquisition/processing modular and the NB-IoTs communication modular. The EO-TENG follows an elastic origami structure design and can convert the low-frequency impact vibration energy into multiple frequency current output. With the integrated PMC, the EO-TENG array can provide the stable direct current (DC) voltage on the external load. Furthermore, the EO-TENG array with power management circuit (PMC) and energy storage device can drive the data processing modular to obtain and process vibration signals from piezoelectric patch. The NB-IoTs communication modular can send the vibration information to the terminal. Our design can provide a new system framework for TENG device in the bridge monitoring field. This design will promote the application of TENGs in the bridge monitoring field. [Display omitted] • To build the self-powered bridge health monitoring system, we designed an elastic origami structure triboelectric nanogenerator (EO-TENG) to harvest impact vibration energy. • According to the experimental results, when the impact amplitude and frequency are 2.4 cm and 1 Hz, the instantaneous open circuit voltage (V oc) and short-circuit current (I sc) of EO-TENG reach 105 V and 58 µA, respectively. • The EO-TENG array with PMC and energy storage device can drive the data processing modular to obtain and process vibration signals from the piezoelectric patch. The NB-IoTs communication modular can send the vibration information to the terminal [ABSTRACT FROM AUTHOR]

Flexible thermoelectric (TE) devices offer great potential for wearable thermal management and self-powered systems, but heat dissipation and electrical interconnection remain key challenges. In this study, we address these issues by integrating flexible TE devices with phase-change material (PCM) heatsinks and stretchable semi-liquid metal (semi-LM) interconnectors. The effectiveness of PCMs with varying melting points for temperature regulation in different environmental conditions is demonstrated, delivering cooling effects exceeding 10 °C. Furthermore, the utilization of semi-LMs instead of LMs enables excellent stretchability and efficient heat dissipation. Moreover, the TE devices generate power with a density of 7.3 μW/cm 2 at an ambient temperature of 22 °C, making it an ideal power source for a wearable self-powered sensing system. Successful integration into garments and armbands confirms the practicality and adaptability of these flexible thermoelectric devices, establishing them as critical components for future wearables with superior resilience to daily wear and tear.

Harvesting energy from environment is an efficient and convenient way to supply power for self-powered systems. Here we present a flexible and reliable microfluidics nanogenerator (MFNG), which can convert environmental mechanical energy into electricity by utilizing the streaming potential effect. A MFNG with the effective sectional area of 1 mm 2 can produce a pulse voltage of ~1.5 V and current of ~1 μA. The output performance of the MFNG can be further promoted by optimizing the type of fluidic liquid, concentration of solution, surface property of microchannels as well as the size of the microchannels. Moreover, we demonstrate the application of the MFNG by powering a LCD directly with a gentle finger press and lighting a LED after charging a capacitor. These results may offer an approach for building up self-powered systems by harvesting human mechanical energies. [ABSTRACT FROM AUTHOR]

A facile fabrication of high-performance flexible all-solid-state carbon micro-supercapacitors (MSCs) with highly improved energy and power densities is demonstrated by laser direct writing on polyimide films using a 405 nm blue–violet semiconductor laser in an Ar atmosphere. The capacitive performance was significantly improved by changing the laser irradiation atmosphere from air to an inert atmosphere of Ar gas. The improvements were attributed to a better conductivity, larger surface area, and a narrower pore distribution of the carbon electrodes fabricated in Ar. The MSC performance can be further improved by air-plasma treatment which improves the interfacial contact between the carbon structures and the electrolyte. Moreover, the MSCs showed excellent cycling stability, good flexibility, and the capability of operating at high energies and voltages when connecting MSCs in series or parallel arrangements. The MSCs can act as energy storage units and stabilizers in self-powered systems in combination with commercial solar panels. Furthermore, an on-chip self-powered UV-light detection system with a high on/off ratio and fast response was demonstrated by combining a commercial solar panel with an in-plane integrated circuit comprising an MSC and a ZnO nanoparticles-based photodetector prepared by a one-step laser direct writing process. [ABSTRACT FROM AUTHOR]

We designed a piezoelectric energy harvesting system for self-powering a system like a black box that records the vibration and acceleration data of trains for their safety and health monitoring. To make the recording system self-powered, this harvesting system harvests inertial energy as well as vibration energy. To harvest these energies maximally, we proposed the piezoelectric energy harvesting system with magnetic pendulum movement (PEH-MPM). In this system, there are two magnets: one located at the end of a pendulum rod and the other located at the free end of a piezoelectric cantilever with an acrylic case. The vibration data was acquired from an actual passenger train. When the train moves, the magnet on the pendulum rod makes the piezoelectric cantilever vibrate, amplifying movement of the magnet at its free end. We set structural conditions such as the magnet thickness, length of the pendulum rod, and distance between the magnets. We determined optimizing conditions for increasing output power by changing three conditions: pendulum direction, magnetic pole, and load resistance. The pendulum directions investigated were the X-direction in the direction of train motion and the Y-direction, perpendicular to train motion. The magnetic pole was either attraction or repulsion between the pendulum magnet and the tip magnet. Finally, the impedance varied from 10 kΩ to 1000 kΩ. The system’s output power varied considerably with these three conditions. In conclusion, the optimizing conditions were pendulum motion in the Y-direction, an attractive magnetic pole, and an impedance of 200 kΩ. Under these conditions, the system generated 40.24 μW/cm 3 . This output power density is possible to be used as a power source for the safety sensor in trains. [ABSTRACT FROM AUTHOR]