Search

Wind power is one of the most attractive frontrunners of the technological breakthroughs that might lead to more efficient energy production. However, the implementation of wind energy is seriously delayed due to the lack of technological advancements that can solve the costs and regional deployment issues. Here, a hybridized design of pinwheel with coupled triboelectric nanogenerator (TENG) and electromagnetic generator (EMG) that can harvest wind energy even in a light breeze is reported. For example, at 1.7 m/s wind speed, the Isc and Voc of the TENG part can reach 1.8 μA and 24 V, while the electric signals of the EMG are 3.8 mA and 0.95 V. Specially, the pinwheel with sole TENG can produce an output of 1.3 μA and 20 V at 1.3 m/s. At 6 m/s wind speed, the TENG part provides a maximum output power density of 0.12 mW/g and the EMG part gives a peak output power density of 0.26 mW/g. Furthermore, the pinwheel can not only charge capacitors but also power mobile phones, hygrometers and some other low-power portable electronic devices, which makes perfect sense in situations even with a very low annual average wind speed.

The human body has an abundance of available energy from the mechanical movements of walking, jumping, and running. Many devices such as electromagnetic, piezoelectric, and triboelectric energy harvesting devices have been demonstrated to convert body mechanical energy into electricity, which can be used to power various wearable and implantable electronics. However, the complicated structure, high cost of production/maintenance, and limitation of wearing and implantation sites restrict the development and commercialization of the body energy harvesters. Here, we present a body-integrated self-powered system (BISS) that is a succinct, highly efficient, and cost-effective method to scavenge energy from human motions. The biomechanical energy of the moving human body can be harvested through a piece of electrode attached to skin. The basic principle of the BISS is inspired by the comprehensive effect of triboelectrification between soles and floor and electrification of the human body. We have proven the feasibility of powering electronics using the BISS in vitro and in vivo. Our investigation of the BISS exhibits an extraordinarily simple, economical, and applicable strategy to harvest energy from human body movements, which has great potential for practical applications of self-powered wearable and implantable electronics in the future.

Wearable electronic devices have attracted numerous attention in tactile sensing, motion detecting, and biomedical signal monitoring. In particular, a wearable and self-powered sensor combining all the merits of sensitivity, transparency, stretchability, and flexibility is highly demanded to adapt human skins. Herein, we report a fully transparent, highly stretchable, and self-powered contact-separation triboelectric nanogenerator (TENG) as a tactile sensor. The TENG consists of a double-network ionogel with the transparency, stretchability, and conductivity as the electrode and one friction layer, and patterned polydimethylsiloxane (PDMS) as another friction layer. The fabricated sensor reaches a maximum sensitivity of 1.76 V N−1 when detecting impacting forces in the range of 0.1–1 N. Meanwhile, with good stretchability of the sensor, the triboelectric signals maintain a good linearity with impacting forces at different tensile ratios (0%, 10%, 50%, and 80% strain). These properties enable the sensor to be capable of monitoring a variety of human activities, including finger touching and bending, breathing, and pulse beating. We believe such a transparent, stretchable and self-powered tactile TENG sensor has tremendous application potential in wearable and soft electronics.

Conversion of mechanical energy into electricity using triboelectric nanogenerators (TENGs) is a rapidly expanding research area. Although the theoretical origin of TENGs has been proven using the Maxwell's displacement current (ID), a profound quantitative understanding of its generation is not available. Moreover, a comprehensive analysis of the fundamental charging behavior of TENGs and building a standard to evaluate each TENG's unique charging characteristic are critical to ensure efficient use of them in practice. We present a thorough analysis of TENG's charging behavior through which a more complete evaluation of TENG charging is proposed by introducing the structural figure of merit (FOMCs) in a charging system (powering capacitors). The analysis is based on Maxwell's displacement current and results are verified experimentally. To achieve this, according to the distance-dependent electric field model, we provide a systematic discussion on the generation of ID in TENGs, along with the derived analytical formula and numerical calculations. This work suggests a new way to deeply understand the nature of the ID generated within the TENGs; and the modified FOMCS can be used to predict the charging characteristics of TENGs in an energy storage system, allowing us to utilize the TENGs more efficiently towards different applications.

Applying flexible materials for energy scavenging from ambient mechanical vibrations is a clean energy solution that can help alleviate electrical power demands in portable devices and wearable electronics. This work presents fundamental studies on a flexible ferroelectret polymer with a strong piezoelectric effect and its interface with self-powered and energy storage systems. A single-layered device with a thickness of 80 μm was used for characterizing the device's output voltage, current, transferred charge, and energy conversion efficiency. The potential capability of harvesting mechanical energy and delivering to system load is demonstrated by integrating the device into a fully integrated power management system. The theory for determining the harvested energy that is ultimately delivered to external electronic loads (or stored in a battery) is discussed. The maximum power delivery is found to be for a 600 MΩ load, which results in a device power density of 14.0 W/m3 for input mechanical forces with a frequency around 2 Hz.

Self-powered implantable medical electronic devices that harvest biomechanical energy from cardiac motion, respiratory movement and blood flow are part of a paradigm shift that is on the horizon. Here, we demonstrate a fully implanted symbiotic pacemaker based on an implantable triboelectric nanogenerator, which achieves energy harvesting and storage as well as cardiac pacing on a large-animal scale. The symbiotic pacemaker successfully corrects sinus arrhythmia and prevents deterioration. The open circuit voltage of an implantable triboelectric nanogenerator reaches up to 65.2 V. The energy harvested from each cardiac motion cycle is 0.495 μJ, which is higher than the required endocardial pacing threshold energy (0.377 μJ). Implantable triboelectric nanogenerators for implantable medical devices offer advantages of excellent output performance, high power density, and good durability, and are expected to find application in fields of treatment and diagnosis as in vivo symbiotic bioelectronics. Implantable medical electronic devices are limited by battery lifetime and inflexibility, but self-powered devices can harvest biomechanical energy. Here the authors demonstrate cardiac pacing and correction of sinus arrhythmia with a symbiotic cardiac pacemaker, which is an implanted self-powered pacing system powered by cardiac motion, in a swine.

Realizing single-mode-lasing output while being able to dynamically select and regulate a specified resonant mode could bring revolutionary impact for laser technology, on-chip data communication, and optical sensing/switches. Here, we demonstrate a single-mode lasing achieved by the piezoresistive and piezoelectric polarization synergistic effect on an epoxy-encapsulated ZnO microresonator. Based on relative shifts of gain spectrum and the resonant wavelength, the lasing mode in a hexagonal ZnO rod can be selected and regulated dynamically within a certain range. The relationship between the corresponding applied strain and the tunable refractive index is analyzed in depth and discussed systematically. Our studies open up exciting avenues for constructing optical mode-phase modulator, high-sensitive optical switches and color-perceived optical sensing.

Entropy was first introduced in thermodynamics for describing the statistical behavior of molecules. In this paper, we use the entropy theory to describe the distribution and powering of small electronics in the era of internet of things. We refer the power transmitted from power plants to utility units as “ordered” energy for fixed sites, while refer the energy harvested from environment as “random” energy. Our conclusion is that the “ordered” energy is able to solve part of the power need for distributed electronics for IoTs, but the remaining part has to be supplied by the “random” energy harvested from our living environment using resources such as solar, vibration, motion and even thermal. The entropy idea defines the role played by energy harvesting as it will become increasingly important owing to the ever expanding usage of distributed electronics at the time of intelligence.

InGaN-based photovoltaics (PV) devices have attracted great attentions because of the excellent photoelectric performance over the past decades. The photocurrent of the InGaN/GaN MQWs solar cells could be further improved by coupling plasmonic with piezo-phototronic effect. Here, we fabricated an InGaN/GaN MQWs solar cells with Ag nanoparticles and the short circuit current of the solar cell was improved by 40% with a static external strain applied. The transmission spectrum and the electromagnetic field distributions of the nanoparticles array were simulated with a finite element analysis model. The physical mechanism for light absorption enhancement by the coupling effect in the quantum well structures was illuminated through a self-consistent numerical calculation with non-linear piezoelectricity polarization. This work demonstrated the coupling between the plasmonic and piezo-phototronic effect achieves significant increase in InGaN/GaN MQWs solar cell power conversion efficiency without any complicated process involved.

Wave monitoring is essential for marine engineering construction, development and utilization of ocean resources, maritime safety and early warning of marine disasters. In this paper, a highly-sensitive wave sensor based on liquid-solid interfacing triboelectric nanogenerator is proposed and systematically investigated. The wave sensor is made of a copper electrode covered by a poly-tetra-fluoroethylene film with microstructural surface. The effects of substrate, wave height, frequency, and water salinity on the performance of wave sensor are systematically investigated. It is found that the output voltage increases linearly with wave height with a sensitivity of 23.5 mV/mm for the electrode width of 10 mm, implying that the wave sensor could sense the wave height in the millimeter range. The sensitivity could be further increased by widening the electrode and/or enhancing the surface hydrophobicity. In a water wave tank, the wave sensor is successfully used to monitor wave around a simulated offshore platform in real time. Therefore, the novel wave sensor could provide an alternative to monitor wave for smart marine equipment.

Triboelectrification is a well-known phenomenon that commonly occurs in nature and in our lives at any time and any place. Although each and every material exhibits triboelectrification, its quantification has not been standardized. A triboelectric series has been qualitatively ranked with regards to triboelectric polarization. Here, we introduce a universal standard method to quantify the triboelectric series for a wide range of polymers, establishing quantitative triboelectrification as a fundamental materials property. By measuring the tested materials with a liquid metal in an environment under well-defined conditions, the proposed method standardizes the experimental set up for uniformly quantifying the surface triboelectrification of general materials. The normalized triboelectric charge density is derived to reveal the intrinsic character of polymers for gaining or losing electrons. This quantitative triboelectric series may serve as a textbook standard for implementing the application of triboelectrification for energy harvesting and self-powered sensing., Triboelectric charging is a well-known phenomenon, but triboelectric polarization has only been ranked qualitatively. Here the authors develop a quantified triboelectric series for a wide range of polymers by measuring triboelectric charge density with respect to a liquid metal at well-defined conditions.

To develop highly efficient energy harvesting means to sustainably driving miniaturized portable electronic devices, the hybrid nanogenerators (NGs) are emerging to compensate for the respective shortcomings of either type of NG. However, the crucial factors affecting the output performances of hybrid NGs still exist, such as the driving frequency, phase difference and mismatched impedance. Here, the bimorph-based piezoelectric NG was integrated into the triboelectric NG to construct a hybrid piezo/triboelectric NG (H-P/TENG) for highly efficient mechanical rotation-energy harvesting. Systematic measurements and analyses illustrated the output performance of H-P/TENG was independent of the rotation speed (driving frequency) due to the invariable periodic deformation degree of the H-P/TENG. Both NGs in the H-P/TENG had the identical phase and matched impedance in the same magnitude, which were beneficial for direct coupling of their individual rectified output signals and avoided unnecessary energy loss from the utilization of transformer. Under a low rotation speed of 100 rpm, the proposed H-P/TENG delivered high output voltage, output current and large average power/power density at ~210 V, 395 μA and 10.88 mW/6.04 mW cm−2, respectively. The output voltage/current of the sophisticated H-P/TENG could retain at ~210 V/400 μA under rotation speeds from 50 to 250 rpm. Through integrating an energy managing circuit with the H-P/TENG, we developed a DC power source (stable DC output at 3.6 V) to sustainably drive RF wireless temperature sensing network and commercial electronics. The H-P/TENG was also capable of producing high output voltage (150 V) and current (150 μA) at wind speed of 14 m/s to power 50 LEDs in parallel connection. The distinctive structure and outstanding performance of this hybrid NG is promising for the practical application of self-powered systems and the large-scale energy conversion.

Triboelectric nanogenerator (TENG) is a new emerging and cost-effective technology for harvesting water wave energy because of its unmatchable performance in low frequency and randomly directed motions. Here, we report an approach that significantly increased the output power of spherical TENGs by optimizing both materials and structural design. Fabricated with an acrylic hollow sphere as its shell and a rolling flexible liquid/silicone as the soft core, the soft-contact spherical triboelectric nanogenerator (SS-TENG) presents up to 10-fold enhancement to the maximum output charge compared to that of a conventional Polytetrafluoroethylene (PTFE) based hard-contact one, which is resulted from the significantly increased contact area. Besides, the output is tunable through controlling the softness of the liquid/silicone core. Our finding provides a new optimization methodology for TENGs and enable its more promising usage in harvesting large-scale blue energy from water wave in oceans as well as feeble but ubiquitous wind energy.

Since the discovery of graphene, two-dimensional (2D) materials have been widely applied to field-effect transistors due to their great potential in optoelectronics, photodetectors, intelligent sensors, and neuromorphic devices. By integrating a 2D transistor with a triboelectric nanogenerator (TENG) into a tribotronic transistor, the induced triboelectric potential can readily regulate the charge carrier transport characteristics in the semiconductor channel. The emerging research field of tribotronics (mainly tribotronic transistors) has attracted extensive attention due to their significant applications in various sensation and human–machine interactions. Here, this review summarizes the recent developments of 2D tribotronic transistors. Firstly, the electrical, optoelectronic, and piezoelectric properties of typical 2D materials are introduced. Then, tribotronic tuning at the micro/nanoscale is discussed together with the methodologies of thermionic emission, triboelectricity tunneling, and atomic force microscope probe scanning, which is of great significance for the investigation of the underlying mechanism of the tribotronic effect. In addition, macroscale tribotronic regulation via TENG mechanical displacement is discussed in detail to explore the applications of 2D tribotronic transistors in intelligent sensors, logic devices, memory devices, and artificial synapses. Finally, the challenges and perspectives for 2D tribotronic transistors are discussed.

Gas therapy is an emerging technology for improving cancer therapy with high efficiency and low side effects. However, due to the existence of the gatekeeper of the blood-brain barrier (BBB) and the limited availability of current drug delivery systems, there still have been no reports on gas therapy for intracranial neuroglioma. Herein, an integrated, self-powered, and wirelessly controlled gas-therapy system is reported, which is composed of a self-powered triboelectric nanogenerator (TENG) and an implantable nitric oxide (NO) releasing device for intracranial neuroglioma therapy. In the system, the patient self-driven TENG converts the mechanical energy of body movements into electricity as a sustainable and self-controlled power source. When delivering energy to light a light-emitting diode in the implantable NO releasing device via wireless control, the encapsulated NO donor s-nitrosoglutathione (GSNO) can generate NO gas to locally kill the glioma cells. The efficacy of the proof-of-concept system in subcutaneous 4T1 breast cancer model in mice and intracranial glioblastoma multiforme in rats is verified. This self-powered gas-therapy system has great potential to be an effective adjuvant treatment modality to inhibit tumor growth, relapse, and invasion via teletherapy.

Triboelectric nanogenerators (TENGs) and dielectric elastomer generators (DEGs) are potentially promising energy conversion technologies, but they still have limitations due to their own intrinsic characteristics, including the low energy output of TENGs caused by the air breakdown effect, and external polarization voltage requirement for DEGs, which severely limit their practical applications. Herein, coupling TENG with DEG is proposed to build a mutual beneficial self-excitation hybrid generator (named TDHG) for harvesting distributed and low-quality mechanical energy (high entropy energy). Experimental results demonstrate that the output charges of this TDHG are enhanced by fivefold of that of the conventional charge-excitation TENG, and continuous operation of DEG is also realized by simple mechanical triggering. More importantly, owing to the high peak power contributed by TENG and the long output pulse duration guaranteed by DEG, the TDHG realizes a much higher energy conversion efficiency of 32% in comparison to either the TENG (3.6%) or DEG (13.2%). This work proposes a new design concept for hybridized energy harvester toward highly efficient mechanical energy harvesting.

Flexibility/wearable electronics such as strain/pressure sensors in human-machine interactions (HMI) are highly developed nowadays. However, challenges remain because of the lack of flexibility, fatigue resistance, and versatility, leading to mechanical damage to device materials during practical applications. In this work, a triple-network conductive hydrogel is fabricated by combining 2D Ti

The triboelectric nanogenerator (TENG) developed by Z. L. Wang’s team to harvest random mechanical energy is a promising new energy source for distributed sensing systems in the new era of the internet of things (IoT) and artificial intelligence (AI) for a smart world. TENG has many advantages that make it suitable for a wide range of applications, including energy harvesting, environmental protection, wearable electronics, robotics, and self-powered sensors. Sensing as an important part of TENG applications is gradually expanding, with the in-depth study of TENG sensing in its working principle, material selection, processing technology, system integration, surface treatment, and back-end algorithms by researchers. In industry and academia, fluid dynamics sensing for liquid and air is urgently needed but lacking. In particular, local fluid sensing is difficult and limited to traditional sensors. Fortunately, with advantages for ordinary TENGs and TENGs as fluid dynamics sensors, fluid dynamics sensing can be better realized. Therefore, the paper summarizes the up-to-date work on TENGs as fluid dynamics sensors, discusses the advantages of TENGs as fluid dynamics sensors in-depth, and, most importantly, aims to explore possible new key areas to help guide the future direction of TENG in fluid dynamics sensing by addressing the key challenges.

Triboelectric nanogenerators (TENGs) have intrigued scientists for their potential to alleviate the energy shortage crisis and facilitate self-powered sensors. Triboelectric interfaces containing triboelectric functionalized molecular groups and tunable surface charge densities are important for improving the electrical output capability of TENGs and the versatility of future electronics. In this review, following an introduction to the fundamental progress of TENG systems for mechanic energy harvesting, surface modifications that aim to increase the surface charge density and functionality are highlighted, with an emphasis on interfacial chemical modification and triboelectric energetics/dynamics optimization for efficient electrostatic induction and charge transfer. Recent advances in assemblies of multifunctional triboelectric sensing are briefly introduced, and future challenges and chemical perspectives in the field of TENG-based electronics are concisely reviewed. This review presents and advances the understanding of the state-of-the-art chemical strategies toward rational triboelectric interface engineering and system assembly and is expected to guide the rational design of highly efficient and versatile triboelectric sensing.

The phenomenon of triboelectricity involves the flow of charged species across an interface, but conclusively establishing the nature of the charge transfer has proven extremely difficult, especially for the liquid-solid cases. Herein, we developed a self-powered droplet triboelectric nanogenerator (droplet-TENG) with spatially arranged electrodes as a probe for measuring the charge transfer process between liquid and solid interfaces. The information on the electric signal on spatially arranged electrodes shows that the charge transfer between droplets and the solid is an accumulation process during the dropping and that the electron is the dominant charge-transfer species. Such a droplet-TENG showed a high sensitivity to the ratio of solvents in the mixed organic solution, and we postulated this is due to the possibility of generation of a hydrogen bond, affecting the electric signal on the spatially arranged electrodes. This work demonstrated a chemical sensing application based on the self-powered droplet triboelectric nanogenerator.

The rapid development of Internet of Things and artificial intelligence brings increasing attention on the harvesting of distributed energy by using triboelectric nanogenerator (TENG), especially the direct current TENG (DC-TENG). It is essential to select appropriate triboelectric materials for obtaining a high performance TENG. In this work, we provide a set of rules for selecting the triboelectric materials for DC-TENG based on several basic parameters, including surface charge density, friction coefficient, polarization, utilization rate of charges, and stability. On the basis of the selection rules, polyvinyl chloride, used widely in industry rather than in TENG, is selected as the triboelectric layer. Its effective charge density can reach up to ~8.80 mC m−2 in a microstructure-designed DC-TENG, which is a new record for all kinds of TENGs. This work can offer a basic guideline for the triboelectric materials selection and promote the practical applications of DC-TENG., Appropriate triboelectric material selection is vital to for high performance direct current triboelectric nanogenerator (DC-TENG). The authors here provide effective selection rules as guideline to select triboelectric materials for DC-TENG to reduce the trial-and-error cost for DC-TENG’s research.

Leaf coloration changes evoke different photosynthetic responses among different poplar cultivars. The aim of this study is to investigate the photosynthetic difference between a red leaf cultivar (ZHP) and a green leaf (L2025) cultivar of Populus deltoides. In this study, ‘ZHP’ exhibited wide ranges and huge potential for absorption and utilization of light energy and CO2 concentration which were similar to those in ‘L2025’ and even showed a stronger absorption for weak light. However, with the increasing light intensity and CO2 concentration, the photosynthetic capacity in both ‘L2025’ and ‘ZHP’ was gradually restricted, and the net photosynthetic rate (Pn) in ‘ZHP’ was significantly lower than that in ‘L2025’under high light or high CO2 conditions, which was mainly attributed to stomatal regulation and different photosynthetic efficiency (including the light energy utilization efficiency and photosynthetic CO2 assimilation efficiency) in these two poplars. Moreover, the higher anthocyanin content in ‘ZHP’ than that in ‘L2025’ was considered to be closely related to the decreased photosynthetic efficiency in ‘ZHP’. According to the results from the JIP-test, the capture efficiency of the reaction center for light energy in ‘L2025’ was significantly higher than that in ‘ZHP’. Interestingly, the higher levels of light quantum caused relatively higher accumulation of QA- in ‘L2025’, which blocked the electron transport and weakened the photosystem II (PSII) performance as compared with ‘ZHP’, however, the decreased capture of light quantum also could not promote the utilization of light energy, which was the key to the low photosynthetic efficiency in ‘ZHP’. The differential expressions of a series of photosynthesis-related genes further promoted these specific photosynthetic processes between ‘L2025’ and ‘ZHP’.

The past few decades have witnessed the tremendous progress of human–machine interface (HMI) in communication, education, and manufacturing fields. However, due to signal acquisition devices’ limitations, the research on HMI related to communication aid applications for the disabled is progressing slowly. Here, inspired by frogs’ croaking behavior, a bionic triboelectric nanogenerator (TENG)‐based ultra‐sensitive self‐powered electromechanical sensor for muscle‐triggered communication HMI application is developed. The sensor possesses a high sensitivity (54.6 mV mm−1), a high‐intensity signal (± 700 mV), and a wide sensing range (0–5 mm). The signal intensity is 206 times higher than that of traditional biopotential electromyography methods. By leveraging machine learning algorithms and Morse code, the safe, accurate (96.3%), and stable communication aid HMI applications are achieved. The authors' bionic TENG‐based electromechanical sensor provides a valuable toolkit for HMI applications of the disabled, and it brings new insights into the interdisciplinary cross‐integration between TENG technology and bionics., Inspired by frogs’ croaking behavior, a bionic triboelectric nanogenerator‐based ultra‐sensitive self‐powered electromechanical sensor is developed for muscle‐triggered communication human–machine interface (HMI) application. The sensor possesses a high sensitivity, a high‐intensity signal, and a wide sensing range. By leveraging machine learning algorithms and Morse code, the safe, accurate, and stable communication aid HMI applications are achieved.

Contact electrification (CE) is a common physical phenomenon, and its mechanisms for solid-solid and liquid-solid cases have been widely discussed. However, the studies about liquid-liquid CE are hindered by the lack of proper techniques. Here, a contactless method is proposed for quantifying the charges on a liquid droplet based on the combination of electric field and acoustic field. The liquid droplet is suspended in an acoustic field, and an electric field force is created on the droplet to balance the acoustic trap force. The amount of charges on the droplet is thus calculated based on the equilibrium of forces. Further, the liquid-solid and liquid-liquid CE are both studied by using the method, and the latter is focused. The behavior of negatively precharged liquid droplet in the liquid-liquid CE is found to be different from that of the positively precharged one. The results show that the silicone oil droplet prefers to receive negative charges from a negatively charged aqueous droplet rather than positive charges from a positively charged aqueous droplet, which provides a strong evidence about the dominant role played by electron transfer in the liquid-liquid CE.

With the great progress in human activities and production technologies, the waste inevitably produced causes not only environmental pollution but also resource waste; meanwhile, the mobile and portable electronic devices urgently need a distributed and sustainable energy source to ensure their stable operation. Here, the waste pollutants (milk cartons) generated from daily life, commonly associated with environmental concerns, are instead identified as an available resource for preparing an emerging energy harvester (triboelectric nanogenerator, TENG), which can convert ubiquitous mechanical energy into electric power. Consequently, based on the waste material, the initial charge density of the TENG is as low as 0.035 mC m-2, which can be tremendously improved to 1.00 mC m-2 through combining a charge excitation circuit, achieving efficient energy harvesting. In addition, compared to the common dielectric film, the waste material can reduce the cost and simplify the process of the preparation of TENG. This work provides not only an innovative approach to simultaneously realize environmental protection and energy harvesting but also more material choice for the preparation of a low-cost and high-performance TENG.

Power devices for the smart sensor networks of Internet of things (IoT) are required with minimum or even no maintenance due to their enormous quantities and widespread distribution. Self-charging power systems (SCPSs) refer to integrated energy devices with simultaneous energy harvesting, power management and effective energy storage capabilities, which may need no extra battery recharging and can sustainably drive sensors. Herein, we focus on the progress made in the field of nanogenerator-based SCPSs, which harvest mechanical energy using the Maxwell displacement current arising from the variation in the surface-polarized-charge-induced electrical field. Prototypes of different nanogenerator-based SCPSs will be overviewed. Finally, challenges and prospects in this field will be discussed., Recent progresses and future prospects on nanogenerator-based self-charging power systems (SCPSs) are discussed with this perspective.

Contact electrification (triboelectrification) has been a long-standing phenomenon for 2600 years. The scientific understanding of contact electrification (triboelectrification) remains un-unified as the term itself implies complex phenomena involving mechanical contact/sliding of two materials involving many physico-chemical processes. Recent experimental evidence suggests that electron transfer occurs in contact electrification between solids and liquids besides the traditional belief of ion adsorption. Here, we have illustrated the Density Functional Theory (DFT) formalism based on a first-principles theory coupled with temperature-dependent ab initio molecular dynamics to describe the phenomenon of interfacial charge transfer. The model captures charge transfer dynamics upon adsorption of different ions and molecules on AlN (001), GaN (001), and Si (001) surfaces, which reveals the influence of interfacial charge transfer and can predict charge transfer differences between materials. We have depicted the substantial difference in charge transfer between fluids and solids when different ions (ions that contribute to physiological pH variations in aqueous solutions, e.g., HCl for acidic pH, and NaOH for alkaline pH) are adsorbed on the surfaces. Moreover, a clear picture has been provided based on the electron localization function as conclusive evidence of contact electrification, which may shed light on solid-liquid interfaces.

Harvesting distributed and low-quality mechanical energies by triboelectric nanogenerators to power electrochemical reactions is beneficial to electric energy saving and certain applications. However, the conventional self-powered electrochemical process is awkward about the reaction rate, energy conversion efficiency, high-operation frequency, and mismatched impedance. Here we demonstrate an advanced self-powered electrochemical system. In comparison with the conventional system that is inert in activity, the superior power management and electrochemical reaction regulation in tandem make the novel system outstanding for hydrogen peroxide production. In addition to the visible product, an internal current efficiency of 24.6% in the system was achieved. The developed system provides an optimization strategy toward electric energy saving for electrochemical reactions as well as enabling their applications in remote areas by converting environmental mechanical vibrational energy for ecological improvement or recyclable chemical fuel generation.