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Nowadays, magnetic materials are also drawing considerable attention in the development of innovative energy converters such as triboelectric nanogenerators (TENGs), where the introduction of magnetic materials at the triboelectric interface not only significantly enhances the energy harvesting efficiency but also promotes TENG entry into the era of intelligence and multifunction. In this review, we begin from the basic operating principle of TENGs and then summarize the recent progress in applications of magnetic materials in the design of TENG magnetic materials by categorizing them into soft ferrites and amorphous and nanocrystalline alloys. While highlighting key role of magnetic materials in and future opportunities for improving their performance in energy conversion, we also discuss the most promising choices available today and describe emerging approaches to create even better magnetic TENGs and TENG-based sensors as far as intelligence and multifunctionality are concerned. In addition, the paper also discusses the integration of magnetic TENGs as a power source for third-party sensors and briefly explains the self-powered applications in a wide range of related fields. Finally, the paper discusses the challenges and prospects of magnetic TENGs. [ABSTRACT FROM AUTHOR]

In advancing the transition of the energy sector toward heightened sustainability and environmental friendliness, biopolymers have emerged as key elements in the construction of triboelectric nanogenerators (TENGs) due to their renewable sources and excellent biodegradability. The development of these TENG devices is of significant importance to the next generation of renewable and sustainable energy technologies based on carbon-neutral materials. This paper introduces the working principles, material sources, and wide-ranging applications of biopolymer-based triboelectric nanogenerators (BP-TENGs). It focuses on the various categories of biopolymers, ranging from natural sources to microbial and chemical synthesis, showcasing their significant potential in enhancing TENG performance and expanding their application scope, while emphasizing their notable advantages in biocompatibility and environmental sustainability. To gain deeper insights into future trends, we discuss the practical applications of BP-TENG in different fields, categorizing them into energy harvesting, healthcare, and environmental monitoring. Finally, the paper reveals the shortcomings, challenges, and possible solutions of BP-TENG, aiming to promote the advancement and application of biopolymer-based TENG technology. We hope this review will inspire the further development of BP-TENG towards more efficient energy conversion and broader applications. [ABSTRACT FROM AUTHOR]

Energy storage devices such as supercapacitors (SCs), if equipped with built-in energy harvesters such as piezoelectric nanogenerators, will continuously power wearable electronics and become important enablers of the future Internet of Things. As wearable gadgets become flexible, energy items that can be fabricated with greater compliance will be crucial, and designing them with sustainable and flexible strategies for future use will be important. In this review, flexible supercapacitors designed with built-in nanogenerators, mainly piezoelectric nanogenerators, are discussed in terms of their operational principles, device configuration, and material selection, with a focus on their application in flexible wearable electronics. While the structural design and materials selection are highlighted, the current shortcomings and challenges in the emerging field of nanogenerators that can be integrated into flexible supercapacitors are also discussed to make wearable devices more comfortable and sustainable. We hope this work may provide references, future directions, and new perspectives for the development of electrochemical power sources that can charge themselves by harvesting mechanical energy from the ambient environment. [ABSTRACT FROM AUTHOR]

The rapid development of smart devices and electronic products puts forward higher requirements for power supply components. As a promising solution, hybrid energy harvesters that are based on a triboelectric nanogenerator (HEHTNG) show advantages of both high energy harvesting efficiency and multifunctionality. Aiming to systematically elaborate the latest research progress of a HEHTNG, this review starts by introducing its working principle with a focus on the combination of triboelectric nanogenerators with various other energy harvesters, such as piezoelectric nanogenerators, thermoelectric/pyroelectric nanogenerators, solar cells, and electromagnetic nanogenerators. While the performance improvement and integration strategies of HEHTNG toward environmental energy harvesting are emphasized, the latest applications of HEHTNGs as multifunctional sensors in human health detection are also illustrated. Finally, we discuss the main challenges and prospects of HEHTNGs, hoping that this work can provide a clear direction for the future development of intelligent energy harvesting systems for the Internet of Things. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) have revolutionized energy harvesting and active sensing, holding tremendous potential in personalized healthcare, sustainable diagnoses, and green energy applications. In these scenarios, conductive polymers play a vital role in enhancing the performance of both TENG and TENG-based biosensors, enabling the development of flexible, wearable, and highly sensitive diagnostic devices. This review summarizes the impact of conductive polymers on TENG-based sensors, focusing on their contributions to triboelectric properties, sensitivity, detection limits, and wearability. We discuss various strategies for incorporating conductive polymers into TENG-based biosensors, promoting the creation of innovative and customizable devices tailored for specific healthcare applications. Additionally, we consider the potential of integrating TENG-based sensors with energy storage devices, signal conditioning circuits, and wireless communication modules, ultimately leading to the development of advanced, self-powered diagnostic systems. Finally, we outline the challenges and future directions in developing TENGs that integrate conducting polymers for personalized healthcare, emphasizing the need to improve biocompatibility, stability, and device integration for practical applications. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) have garnered considerable interest as a promising technology for energy harvesting and stimulus sensing. While TENGs facilitate the generation of electricity from micro-motions, the modular design of TENG-based modular sensing systems (TMSs) also offers significant potential for powering biosensors and other medical devices, thus reducing dependence on external power sources and enabling biological processes to be monitored in real time. Moreover, TENGs can be customised and personalized to address individual patient needs while ensuring biocompatibility and safety, ultimately enhancing the efficiency and security of diagnosis and treatment. In this review, we concentrate on recent advancements in the modular design of TMSs for clinical applications with an emphasis on their potential for personalised real-time diagnosis. We also examine the design and fabrication of TMSs, their sensitivity and specificity, and their capabilities of detecting biomarkers for disease diagnosis and monitoring. Furthermore, we investigate the application of TENGs to energy harvesting and real-time monitoring in wearable and implantable medical devices, underscore the promising prospects of personalised and modular TMSs in advancing real-time diagnosis for clinical applications, and offer insights into the future direction of this burgeoning field. [ABSTRACT FROM AUTHOR]

The ever-growing interest in wearable electronic devices has unleashed a strong demand for sustainable and flexible power sources that are represented by the combination of flexible energy harvesting with storage devices/technologies. Triboelectric nanogenerators (TENG), which harvest mechanical energy and charge their matching supercapacitors (SCs), may form a distributed power system with flexibility to tap their potential applications in powering wearable electronic devices. This review aims to cover the recent progress in the integration of TENG with flexible SC in terms of operation principle, material selection, device configuration and power management, with an accent on the application scenario in flexible wearable electronics. Further, the current shortcomings, challenges and new prospects for future developments in the emerging field of integrated flexible TENG-SCs for self-powered wearable electronics are discussed. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators have attracted extensive attention in energy harvesting due to its light weight, low cost, high flexibility, and diversity of function. However, deterioration in terms of mechanical durability and electrical stability of the triboelectric interface during operation, which are the results of material abrasion, severely limits their practical applications. In this paper, a durable triboelectric nanogenerator inspired by a ball mill was designed by using metal balls in hollow drums as carriers for charge generation and transfer. Composite nanofibers were deposited onto the balls, increasing the triboelectrification with the interdigital electrodes in the inner surface of the drum for higher output and electrostatic repulsion to each other for lower wear. Such a rolling design cannot only increase mechanical durability and maintenance convenience, where the filler can be easily replaced and recycled but also collect wind power with the decreased wearing of materials and sound efficiency in comparison with the typical rotation TENG. In addition, the short circuit current shows a strong linear relationship with the rotation speed in a wide range, which can be used to detect wind speed, thus showing potential applications in distributed energy conversion and self-powered environmental monitoring systems. [ABSTRACT FROM AUTHOR]

Piezoelectric and triboelectric nanogenerators have been widely studied in the past years for their advantages of easy design/manufacturing, small size, and flexibility. Nanogenerators that are developed based on the coupled piezoelectric and triboelectric effects (PTCNG) can make full use of the mechanical energies and achieve both higher output and sensing performance. This review aims to cover the recent research progress of PTCNG by presenting in detail their key technologies in terms of operating principles, integration concept, and performance enhancement strategies, with a focus on their structural simplification and efficiency performance improvement. The latest applications of PTCNG in tactile sensors and energy-harvesting system are also illustrated. Finally, we discuss the main challenges and prospects for the future development of PTCNG, hoping that this work can provide a new insight into the development of all-in-one mechanical energy-scavenging and sensing devices. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) were initially invented as an innovative energy−harvesting technology for scavenging mechanical energy from our bodies or the ambient environment. Through adaptive customization design, TENGs have also become a promising player in the self-powered wearable medical market for improving physical fitness and sustaining a healthy lifestyle. In addition to simultaneously harvesting our body's mechanical energy and actively detecting our physiological parameters and metabolic status, TENGs can also provide personalized medical treatment solutions in a self-powered modality. This review aims to cover the recent advances in TENG-based electronics in clinical applications, beginning from the basic working principles of TENGs and their general operation modes, continuing to the harvesting of bioenergy from the human body, and arriving at their adaptive design toward applications in chronic disease diagnosis and long-term clinical treatment. Considering the highly personalized usage scenarios, special attention is paid to customized modules that are based on TENGs and support complex medical treatments, where sustainability, biodegradability, compliance, and bio-friendliness may be critical for the operation of clinical systems. While this review provides a comprehensive understanding of TENG-based clinical devices that aims to reach a high level of technological readiness, the challenges and shortcomings of TENG-based clinical devices are also highlighted, with the expectation of providing a useful reference for the further development of such customized healthcare systems and the transfer of their technical capabilities into real-life patient care. [ABSTRACT FROM AUTHOR]

Triboelectric active composites that are built with high thermal conductivity and wear-resistance are of prime importance for the long-term operation of triboelectric nanogenerators (TENGs) in harsh environments. In this paper, it's demonstrated that the introduction of B 4 C particles into poly(vinylidene fluoride) (PVDF) leads to a thermal conductivity of 0.727 W/(m·k), which is 600 % higher than that of pure PVDF film, and a significant reduction of 39.7 % in the average friction mass loss of the B 4 C/PVDF. Enhanced anti-corrosion and electrical output performance are also observed, including an open-circuit voltage of 155.4 V, a short-circuit current of 7.9 μA, as well as a maximum output power density of 0.33 W/m2, which are 2.6, 6, and 12 times higher than those of pure PVDF devices, respectively. Interestingly, such a performance grows steadily, rather than degrades, with the operation time, which is sharply differentiated from that observed from other common composites and may be partly ascribed to the roughened surface of the composite film. This work demonstrates an effective strategy for improving the wear resistance and thermal conductivity of the triboelectric material for high-performance energy harvesting and self-powered sensing that are based on BP-TENG for long-term operation. [Display omitted] • Triboelectrically active B 4 C/PVDF composite films were developed for the robust TENG for operation in harsh environments. • High thermal conductivity, wear-resistance and anti-corrosion property were demonstrated by the B 4 C/PVDF composite films. • Significantly enhanced output performance of the BP-TENG was obtained in comparison with that built with pure PVDF film. • Extraordinary output growth is observed in long-term work, whereas performance degradation is common in other materials. [ABSTRACT FROM AUTHOR]

High performance and versatility may be the key for the development of flexible electronic skins that are based on triboelectric nanogenerators (TENGs), and multifunctional components at the triboelectric interface is essential for empowering these devices to mimic or even surpass the sensing properties of human skin, and enabling their response to both environmental and intrinsic conditions. In this context, we present an efficient, low-cost strategy for constructing magnetically responsive TENGs by introducing NdFeB powders into a polydimethylsiloxane film. Besides superior stability, resiliency, and flexibility, the as-designed TENG presents an enhanced output of open circuit voltage of 150 V, short circuit current of 16.7 mA/m2, and Q sc of 35 nC, which is almost 3.5 times of the pristine one. Interestingly, the output performance of MR-TENG shows dependence on both the concentration of NdFeB and the direction and intensity of magnetization. Such a correlation in turn provides the linear relationship of the output with the magnetic field (∼80 V/T) and the applied dynamic force (∼0.64 V/N), which helps seamlessly integrating energy harvesting with tactile sensing for self-powered human activity monitoring and other intelligent sensing applications. [Display omitted] • Magnetically responsive TENGs were built by introducing NdFeB powders into a polydimethylsiloxane film. • The output of as-designed TENG is enhanced almost 3.5 times of the pristine one. • A dependence of the output on both the concentration of NdFeB and intensity of magnetization was observed. • A sensitive reponse to the magnetic field (~80 V/T) and the applied dynamic force (~0.64 V/N) was presented. [ABSTRACT FROM AUTHOR]

Currently, significant advances have been made in the field of high-performance energy storage technologies, such as Li-ion batteries and supercapacitors. However, the limited lifespans, as well as the frequent charging or replacement requirements, pose a set of challenges for their application in the Internet of things (IoTs), because the full power of the IoTs can only be realized by the sustainable operation of physical objects, especially embedded sensors, for the purpose of connecting and exchanging data with other devices and systems continually in real-time. A viable option for achieving the sustainability of the IoTs may be the combination of renewable energy harvesting technologies such as triboelectric nanogenerators (TENGs) with electrochemical energy storage technologies, where TENGs can harvest mechanical energies from ambient environments and transform them into electricity for charging electrochemical batteries and supercapacitors (SCs) conveniently, thus developing a new type of TENG-based uninterrupted power supply (TENG-UPS). In this review, we begin from a brief description of the operating mode of TENG and the integration strategy of TENG-UPS. The latest advances in the TENG-UPS are then thoroughly discussed from the perspective of structural design and system integration. Cutting edge developments of the as-designed self-powered sensing systems are then concisely illustrated to disclose the application potential in the IoTs. The main obstacles and future prospects for developing TENG-UPS-based intelligent systems are also highlighted in terms of design and manufacture at the conclusion. We expect this review will appropriately shine a light on the understanding of the key role of electrochemical energy storage devices in the development of TENG-based energy harvesting technology as well as the self-powered intelligent systems. [ABSTRACT FROM AUTHOR]

Wind energy, one of the most promising and renewable energy sources, is extensively exploited around the world. However, in traditional triboelectric nanogenerator (TENG) for wind energy harvesting, due to the limitations of device structures with high friction force, the collection of wind energy at low speeds is always faced with enormous challenges. To overcome this difficulty, an ultralow friction and highly effective windmill‐like nanogenerator (WNG) is proposed. Herein, the WNG is based on a freestanding mode TENG and adopts a rotational triboelectric layer with contact–separation mode. This special design successfully achieves a smaller friction resistance, allowing wind energy to be captured at low speeds. Under the minimum wind speed, the optimized WNG has a maximum load power of 0.753 µW, which can illuminate nine LEDs simultaneously. The WNG can convert wind energy into enough electricity to power a hygrometer or a digital clock under the maximum wind speed. Moreover, a wind speed detection system based on WNG is developed and proves the superiority of real‐time wind speed detection by appropriate computation parameters. This work not only shows the development potential of the WNG in low‐speed wind energy collection but also expends the application potential of TENG‐based self‐powered environmental monitoring. [ABSTRACT FROM AUTHOR]

As an agricultural waste, peanut shell powder (PSP) is rich in cellulose and lignin, but its traditional treatment not only has additional disposal costs, but also causes environmental pollution. Here, a low‐cost and environment‐friendly triboelectric nanogenerator based on PSP (PSP‐TENG) is designed for efficient wind energy harvesting. PSP film is used as the tribo‐positive layer, with high surface charge density. The maximum output power density of the PSP‐TENG reaches 365 mW m–2 with a short‐circuit current of 39.4 µA and an open‐circuit voltage of 248.9 V. About 228 commercial LEDs can be lighted up by the wind‐driven PSP‐TENG, which can also be used as a sensor to measure the wind speed. By integrating with capacitor, PSP‐TENG can provide continuous and stable power supply for electronic devices, such as hygrometers, calculators, and stopwatches. Besides, an efficient self‐powered cathodic protection system based on PSP‐TENG is designed for anti‐corrosion for marine pipelines and ships. This work provides a simple and environment‐friendly "waste‐to‐energy technology," which has a huge application prospect in agricultural waste treatment, new energy, and self‐powered system. [ABSTRACT FROM AUTHOR]

Nowadays, self-powered wearable biosensors that are based on triboelectric nanogenerators (TENGs) are playing an important role in the continuous efforts towards the miniaturization, energy saving, and intelligence of healthcare devices and Internets of Things (IoTs). In this review, we cover the remarkable developments in TENG−based biosensors developed from various polymer materials and their functionalities, with a focus on wearable and implantable self-powered sensors for health monitoring and therapeutic devices. The functions of TENGs as power sources for third-party biosensors are also discussed, and their applications in a number of related fields are concisely illustrated. Finally, we conclude the review with a discussion of the challenges and problems of leveraging TENG−based intelligent biosensors. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator (TENG) is an effective approach for self‐powered systems. Here, a second‐order Rubik‐cube‐based TENG (SRC‐TENG) is designed, which can harvest the internal sliding energy of the Rubik cube. The influence of different rotation speeds, different strengths, and effective contact area on the output performance of SRC‐TENG is studied. When the SRC‐TENG rotates with a high speed, light strength, and the contact area is 8 cm2, the maximum open‐circuit voltage and short‐circuit current can reach up to 35 V and 1.45 µA, respectively, which are enough to light up dozens of light‐emitting diodes (LEDs) and charge commercial capacitors. In addition, the SRC‐TENG‐based smart toys can act as self‐powered sensors to be applied in smart home. More importantly, the movement trajectory of the Rubik cube in the process of recovery can also be tracked in different directions of X, Y, and Z. The proposed SRC‐TENG is low cost and has great potential to replace battery‐powered electronic toys, which can open a new path for the next‐generation commercial toys. [ABSTRACT FROM AUTHOR]

A useful direction to solve the energy problem is the effective repeated use of biomaterial for mechanical energy collection and sensing applications. Here, a feather‐based single‐electrode triboelectric nanogenerator (F‐STENG) by only sputtering copper atoms on the feathers are presented. The feather of F‐STENG, as a natural material, has environmental friendliness, which is different from the polymer materials of other triboelectric nanogenerators. F‐STENG has super durability due to its feather structure self‐healing property. The device has a high output voltage of 90 V and an output current of 3.5 µA. After breaking and self‐healing lots of times, the output performance is also 80% of the original. F‐STENG has a high sensitivity to temperature, humidity, and wind speed, and the sensitivity is 0.50 V °C−1, ‐0.98 V RH−1, and 1.67 μA m−1 s−1. The output power of F‐STENG is 0.62 mW g−1, which can realize global positioning and photographing to solve the module energy consumption problem. F‐STENG provides an effective way for the application of self‐powered sensors and equipment in military, industrial, transportation, and daily life. [ABSTRACT FROM AUTHOR]

• A water-driven robust TENG was invented based on the lever principle. • The microstructural graphite on the triboelectric layer surface increases its triboelectric output. • The developed TENG is an effective power source for self-powered electrochemical synthesis systems. Harvesting water energy and converting it into electricity by triboelectric nanogenerator (TENG) is an effective strategy to alleviate the energy crisis. In this work, we develop a corrosion- and abrasive-resistant triboelectric layer by employing the graphite powder as the coating filler. Inspired by the lever principle, a robust and corrosion-resistive TENG was designed for converting water energy into gravitational potential energy and then into electricity. It has the potential to apply anywhere with a water level difference. The microstructural graphite on the coating surface not only enhances the corrosion and abrasion resistance but also enhances the effective contact area and triboelectric output of the graphite/epoxy/polyamide (C/EP/PA) coating. The as-designed TENG shows an open-circuit voltage of 300 V and a power output of 1.936 W/m2. Excellent durability and long-term stability were also demonstrated. In this work, the electrochemical synthesis of nanoparticles driven by TENG was firstly reported. Thus, hinting a new and competitive strategy for the commercial application of TENG in self-powered electrochemical systems. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) have potential applications as active sensors or energy harvesters in self‐powered sensors and systems as they enable harvesting and conversion of mechanical energy into electrical energy. TENG development allows high‐efficiency energy harvesting capability and outstanding sensing characteristics, such as excellent output performance, high durability, reliable stability, easy integration, and convenient fabrication, among others. A triboelectric foam (T‐Foam) composed of a foam material with an embedded soft electrode is proposed in this study. The T‐Foam inherits the dominant mechanical properties of the foam material, which allows it to be freely folded, compressed, and kneaded, as well as immediate recovery upon stimulus withdrawal. The durability and stability of the T‐Foam are tested for a 0.1842 g sample; after stamping 14 times with a 158.6 lb tester, its output performance remained nearly identical. These properties indicate that the T‐Foam can be easily integrated into products, such as insoles, schoolbags, and seat mats, to build smart applications for motion, health, and safety monitoring. When driven by a polytetrafluoroethylene plate, a T‐Foam sample of 135 × 135 × 25 mm3 exhibits considerable energy harvesting capability, with the output power as high as 5.46 mW. [ABSTRACT FROM AUTHOR]

In this paper, an eco-friendly and biodegradable triboelectric nanogenerator (SBB-TENG) is proposed based on bacterial cellulose (BC), sodium alginate (SA) with the introduction of barium titanate (BTO) nanoparticles. While all the composite membranes can be fully decomposed by cellulase solution within 7 h, the electrical properties of SBB-TENG are significantly improved due to the synergistic effect of enhanced dielectric constant and surface roughness of the composite membrane. Compared with SA/BC-based TENG (SBC-TENG), the voltage and current of SBB-TENGs are increased by 174 % and 193 %, respectively. In addition, the as-designed SBB TENGs are capable of serving as sensors for biomechanical monitoring, touch sensing and signal control, which greatly contributes to the development of high-performance, green and low-cost TENGs on the base of natural biodegradable materials. [Display omitted] • A triboelectric nanogenerator based on bacterial cellulose, sodium alginate with the introduction of BaTiO 3 nanoparticles is proposed. • All the bacterial-cellulose-based composite membranes can be fully decomposed by cellulase solution within 7 h. • The BTO particles are wrapped in the BC nanofibers, forming a uniform and continuous three-dimensional cellulose-based network structure. • The performance of SBB-TENG is improved due to the synergistic effect of dielectric constant and surface roughness of the composite. • The SBB-TENGs can be used as sensors for biomechanical monitoring, touch sensing, and signal control. [ABSTRACT FROM AUTHOR]

Abstract: Distributed environmental mechanical energy is rarely collected due to its fluctuating amplitudes and low frequency, which is usually attributed as “random” energy. Considering the rapid development of the Internet of things (IoT), there is a great need for a large number of distributed and sustainable power sources. Here, a natural leaf assembled triboelectric nanogenerator (Leaf‐TENG) is designed by utilizing the green leaf as an electrification layer and electrode to effectively harvest environmental mechanical energy. The Leaf‐TENG with good adaptability has the maximum output power of ≈45 mW m−2, which is capable of driving advertising LEDs and commercial electronic temperature sensors. Besides, a tree‐shaped energy harvester is integrated with natural Leaf‐TENG to harvest large‐area environmental mechanical energy. This work provides a new prospect for distributed and environmental‐friendly power sources and has potential applications in the IoT and self‐powered systems. [ABSTRACT FROM AUTHOR]

As an important green energy in our life, natural wind energy is widely applied to generate electricity. In this work, a bionic triboelectric nanogenerator tree composed of supercells with cell I of leaf and cell II of stem is designed for harvesting wind energy by utilizing the coupling effect of contact electrification and electrostatic induction. At the wind speed of 11 m s−1, the fabricated triboelectric nanogenerator tree produces an open‐circuit voltage of 330 V and a short‐circuit current of 59.6 µA. The corresponding output power is 3.6 mW at the matched resistance of 60 MΩ, and 145 light‐emitting diodes can be lightened. Furthermore, a flexible device of a triboelectric nanogenerator tree is fabricated to present potential applications for illumination and advertisement in the long tunnel through harvesting the moving‐generated wind energy. Due to the advantages of light weight, low cost, easy fabrication, and beautiful appearance, the triboelectric nanogenerator tree can find important applications in billboard illuminating, vehicle speed measuring, and so on. [ABSTRACT FROM AUTHOR]

There is a large amount of electromagnetic energy in modern life, but how to utilize the wasted electromagnetic energy from moving objects is still a difficult problem. Here, four 28 W fluorescent tube lamps can be lighted up when a car model slides on a simple power road (SPR) with an instantaneous power density of 11.6 W/m2. An energy-velocity model was proposed to utilize the electromagnetic energy in the constantly friction between the SPR and the car model. It was found that the electromagnetic energy generated by an object moving at a low speed increases with its speed. Besides, the instantaneous power generated by an object in a high-speed collision also increases rapidly with its speed. Moreover, the first SPR was successfully built in an actual road, which opens the door for solving the energy crisis. The energy-velocity model can be also used to explain the signal interference of high-speed railway and improve the positioning accuracy of missile, considerate that the electromagnetic energy produced by the object in motion. The new discovery may contribute to modifying the existing collision theory, conservation of mechanical energy, friction theory, Maxwell's equations, and electromagnetic technology. [Display omitted] • A simple power road was designed and built to harvest the electromagnetic energy generated in the friction and collision. • Four 28 W fluorescent tube lamps can be lighted by the electric energy when a car model slides on the power road. • The instantaneous power generated by an moving object in a high-speed collision increases rapidly with its speed. [ABSTRACT FROM AUTHOR]

The need for cost-effective and sustainable power supplies has spurred a growing interest in hybrid energy harvesting systems, and the most elementary energy production process relies on intermittent solar power. Here, it is shown how the ambient mechanical energy leads to water splitting in a photoelectrochemical (PEC) cell boosted by a triboelectric nanogenerator (TENG). In this strategy, a flexible TENG collects and transforms mechanical energy into electric current, which boosts the PEC water splitting via the charged Li-ion battery. Au nanoparticles are deposited on TiO2 nanoarrays for extending the available light spectrum to visible part by surface plasmon resonance effect, which yields a photocurrent density of 1.32 mA cm−2 under AM 1.5 G illumination and 0.12 mA cm−2 under visible light with a bias of 0.5 V. The TENG-charged battery boosts the water splitting performance through coupling electrolysis and enhanced electron-hole separation efficiency. The hybrid cell exhibits an instantaneous current more than 9 mA with a working electrode area of 0.3 cm2, suggesting a simple but efficient route for simultaneously converting solar radiation and mechanical energy into hydrogen. [ABSTRACT FROM AUTHOR]

The trends in miniaturization of electronic devices give rise to the attention of energy harvesting technologies that gathers tiny wattages of power. Here this study demonstrates an ultrathin flexible single electrode triboelectric nanogenerator (S-TENG) which not only could harvest mechanical energy from human movements and ambient sources, but also could sense instantaneous force without extra energy. The S-TENG, which features an extremely simple structure, has an average output current of 78 μA, lightening up at least 70 LEDs (light-emitting diode). Even tapped by bare finger, it exhibits an output current of 1 μA. The detection sensitivity for instantaneous force sensing is about 0.947 μA MPa−1. Performances of the device are also systematically investigated under various motion types, press force, and triboelectric materials. The S-TENG has great application prospects in sustainable wearable devices, sustainable medical devices, and smart wireless sensor networks owning to its thinness, light weight, energy harvesting, and sensing capacities. [ABSTRACT FROM AUTHOR]

Harvesting biomechanical energy from human motion presents a promising supplement to electrochemical power sources such as batteries for portable electronic devices. In this paper, an array parallelly assembled triboelectric nanogenerator (PS-TENG) is proposed as an inspiration from the structure of accordion. The as-designed TENGs generate sustainable electrical power through hand motion with significantly enhanced electrification efficiency and reliability. The output of the parallelly assembled TENGs (PS-TENGs), which is positively correlated with the frequency of excitation and reciprocating distance, is 2.8 times higher than that of TENG with series electrodes(S-TENGs) under the same operating conditions. In addition, based on PS-TENGs can be used as self-powered sensors for smart home applications. Such a design promotes the application of TENG in powering portable electronic devices. [Display omitted] • TENGs inspired by the accordions are proposed for biomechanical energy harvesting and music responding. • The TENGs generate sustainable electrical power through hand motion with enhanced electrification efficiency and reliability. • The PS-TENGs can be used not only to stretch the exercise arms, but also as a switch to control the music device. • Based on PS-TENGs can be used as self-powered sensors for smart home applications. • Such a design promotes the application of TENG in powering portable electronic devices. [ABSTRACT FROM AUTHOR]

Bioelectricity and triboelectrification are well-known and widely existing phenomena in nature, and the investigation of their mechanisms and utilizations has attracted much attention for a long time. As traditional investigations suggested, the mechanism of electric organs is that the electrocytes are lined up so a current of ions can flow through them, and thus they are stacked in a sequence so that each one adds up to form a potential difference. For varieties of triboelectric generators, most of them feature extremely high voltage but limited current, which is the major challenge to pracitcal utilization. Here, we present a structural bionic design based on the microstructure of electric organs to improve the output current of systematic triboelectric generators. This study correlating electric organs and triboelectric generators not only benefits the practical use of systematic triboelectric generators for energy harvesting, but also offers a new approach to imitate more compositive and tunable electronic devices from biological structures. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) have shown exciting applications in mechanical energy harvesting and self-powered sensing. Aiming at commercial applications, cost reduction and simplification of TENG structures are of great interest. In this work, a lightweight TENG based on the integration of polymer nanowires and a carbon sponge, which serves both as the substrate and an electrode, are reported. Because of the low density of the carbon sponge and the filmy nanowires, the device exhibits a total mass of less than 0.1 g for a volume of 12.5 cm3 and it produces a short-circuit current of 6 μA, open-circuit voltage of 75 V, and a maximum output power of 0.28 W kg−1 under light finger tapping. The device can linearly measure the acceleration at a detection limit down to 0.25 m s−2 and for a detection range from 0.25 m s−2 to 10.0 m s−2. [ABSTRACT FROM AUTHOR]

Harvesting ambient mechanical energy is a key technology for realizing self-powered electronics, which has tremendous applications in wireless sensing networks, implantable devices, portable electronics, etc. The currently reported triboelectric nanogenerator (TENG) mainly uses solid materials, so that the contact between the two layers cannot be 100% with considering the roughness of the surfaces, which greatly reduces the total charge density that can be transferred and thus the total energy conversion efficiency. In this work, a liquid-metal-based triboelectric nanogenerator (LM-TENG) is developed for high power generation through conversion of mechanical energy, which allows a total contact between the metal and the dielectric. Due to that the liquid-solid contact induces large contacting surface and its shape adaptive with the polymer thin films, the LM-TENG exhibits a high output charge density of 430 μC m−2, which is four to five times of that using a solid thin film electrode. And its power density reaches 6.7 W m−2 and 133 kW m−3. More importantly, the instantaneous energy conversion efficiency is demonstrated to be as high as 70.6%. This provides a new approach for improving the performance of the TENG for special applications. Furthermore, the liquid easily fluctuates, which makes the LM-TENG inherently suitable for vibration energy harvesting. [ABSTRACT FROM AUTHOR]

Tires are important parts in creating a great transportation system because they can significantly improve the overall system safety and fuel/power efficiency. The latter is especially important for the mileage of electric vehicles due to the limited electrical storage capacity. Here, green energy tires are designed by incorporating silica tread rubber with triboelectric nanogenerators (TENGs). On the one hand, the silica‐based tread compound sharply cuts off the rolling resistance, improves fuel efficiency and reduces CO2 emissions, and provides all‐around traction without compromising braking. On the other hand, TENG converts frictional energy into electricity without changing the process of traditional tire production, which is able to be used for powering the electronics for automobile safety and automeasuring of tire pressure. The most important point lies in that TENG helps harness static electricity, which at present hinders the large‐scale application of silica‐filled green tires. Interestingly, it is also able to measure tire pressure and road condition from the changes in the output electrical signals, which thus leads to the smart applications of green energy tire in road/tire condition monitoring. [ABSTRACT FROM AUTHOR]

Energy harvesting and power delivery are key technologies for self‐powered systems toward the internet of things, and integration of the two should be prioritized. The dominant mechanism of a triboelectric nanogenerator (TENG) is Maxwell's displacement current, which exists both inside the media/device and in the space surrounding the device. The displacement current transmitted in media inside the device can be collected by wired transmission using two electrodes, while the component that is leaked in to the space surrounding the device can be partially collected wirelessly. Herein, simultaneous collection of power transmitted through wires and wirelessly by a rotating TENG, is demonstrated. The wired component gives an output of ≈2 mA and ≈110 V, and the wireless component using the finite size of the collector gives an output current and voltage of ≈3 µA and ≈17.5 V (power density of 21.8 mW m−2). Small mobile electronics and a digital camera can be charged. The study extends the application of TENGs for practical applications. An integrated rotating triboelectric nanogenerator (TENG) is designed by conjunction of wired and wireless transmissions to collect rotational energy. The integrated rotating TENG with the wireless energy delivery is demonstrated for the electric power supply of smart homes. The hybrid TENG develops the application of Maxwell's displacement current in self‐powered system. [ABSTRACT FROM AUTHOR]

[Display omitted] • Composite sponge with high flexibility and charge trapping capability was developed for fabricating high performance triboelectric nanogenerator. • Dielectric enhancement mechanism was comparatively proved and demonstrated in the CCTO@BT/PDMS composite. • Permittivity and work function were studied in-depth to unravel the origin of the significantly enhanced triboelectric performance. • Highly stable and sensitive motion monitoring sensor was designed for the development of TENG-based self-powered sensing systems. Functional materials that are with high dielectric constant are finding extensive applications in the conversion and storage of energy, which may also be the key for enhancing the output performance of triboelectric nanogenerator (TENG) by dielectrically modulating the charge trapping capability of the triboelectric interface. Here, CaCu 3 Ti 4 O 12 @BaTiO 3 (CCTO@BT) is facilely synthesized for forming in polydimethylsiloxane (PDMS) layer. Due to the strengthened charge induction, the composite sponge with high flexibility and charge trapping capability is developed, and the polymeric sponge TENG (with 2 wt% CCTO@BaTiO 3) demonstrates a high open-circuit voltage of 291.14 V, a short-circuit current of 35.49 µA, and a transfer charge quantity of 80 nC, which are far superior 206% higher than that are modulated by pure CCTO and 480% higher than pure PDMS (the short-circuit current). Dielectric enhancement mechanism was comparatively proved and demonstrated in the CCTO@BT/PDMS composites. To unravel the origin of the significantly enhanced triboelectric performance, permittivity and work function in the sponge were studied in-depth, and the strong internal polarization and potential barrier height were demonstrated. Moreover, the as-fabricated TENG can act as self-powered sensor for monitoring human motions, such as walking, jogging, and jumping ropes. This work provides a new insight into the unique potential of dielectric-modulated output enhancement strategy for unblocking the potential of TENG in energy harvesting and biophysical monitoring. [ABSTRACT FROM AUTHOR]