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Serious climate changes and energy-related environmental problems are currently critical issues in the world. In order to reduce carbon emissions and save our environment, renewable energy harvesting technologies will serve as a key solution in the near future. Among them, triboelectric nanogenerators (TENGs), which is one of the most promising mechanical energy harvesters by means of contact electrification phenomenon, are explosively developing due to abundant wasting mechanical energy sources and a number of superior advantages in a wide availability and selection of materials, relatively simple device configurations, and low-cost processing. Significant experimental and theoretical efforts have been achieved toward understanding fundamental behaviors and a wide range of demonstrations since its report in 2012. As a result, considerable technological advancement has been exhibited and it advances the timeline of achievement in the proposed roadmap. Now, the technology has reached the stage of prototype development with verification of performance beyond the lab scale environment toward its commercialization. In this review, distinguished authors in the world worked together to summarize the state of the art in theory, materials, devices, systems, circuits, and applications in TENG fields. The great research achievements of researchers in this field around the world over the past decade are expected to play a major role in coming to fruition of unexpectedly accelerated technological advances over the next decade.

The perovskite direct current nanogenerator (PDCG) is a novel energy conversion device with remarkable performance and comprehensive prospects. However, the interface of the perovskite Schottky junction still requires further optimization. Herein, an innovative approach by engineering a two-dimensional/three-dimensional (2D/3D) layered structure through phenylethylammonium iodide (PEAI) modification was introduced This novel modification significantly enhances the triboelectric effects in the Cs0.05(FA0.85MA0.15)0.95Pb(I0.85Br0.15)3/aluminum (CsFAMA/Al) Schottky junction PDCG, featuring a rolling structure. The PEAI-modified PDCG demonstrates a substantial improvement in performance, achieving an open circuit voltage (Voc) of 0.69 V, and a short circuit current (Isc) of 1.51 mA. Under 3 W illumination, the current density (Jsc) of PDCG with PEAI could achieve 92.81 A/m2, representing a 1.98-fold enhancement, realizing synergistic energy harvesting from mechanical and light energy. Furthermore, the innovative 2D/3D layer design significantly boosts the PDCG’s operational stability, reducing performance degradation. Notably, after a 9 h aging at 100°C, the Iscof the PDCG modified with PEAI maintained 85 % of its original value, a substantial improvement compared to the 68 % retention observed in the unmodified PDCG. The development of PDCG converting mechanical energy directly into direct current (DC) while possessing characteristics of integration and miniaturization, holds significant practical significance.

A suitable conductive ink for office inkjet printers is important for the convenient design of flexible electrodes for triboelectric nanogenerators (TENG). Ag nanowires (Ag NWs) easily printed with an average short length of 1.65 μm were synthesized by using soluble NaCl as a growth regulator and adjusting the amount of chloride ion. The water-based Ag NWs ink with a low solid content of 1% but with low resistivity was produced. The printed flexible Ag NWs-based electrodes/circuits showed excellent conductivity with RS/R0values kept at 1.03 after bending 50,000 times on PI substrate and an excellent anticlimate property in acidic conditions for 180 h on polyester woven fabric. The sheet resistance was reduced to 4.98 Ω/sqr heated at 30–50 °C for 3 min by a blower due to the formed excellent conductive network when compared to Ag NPs-based electrodes. Finally, the integration of printed Ag NWs electrode and circuits was applied to the TENG, which can be used to predict a robot’s out-of-balance direction by the change of the TENG signal. In all, a suitable conductive ink with a short length of Ag NWs was fabricated, and flexible electrodes/circuits can be conveniently and easily printed by office inkjet printers.

Tribotronics is an emerging research field that focuses on the coupling of triboelectricity and semiconductors. In this review, we summarise and explore three branches of tribotronics. Firstly, we introduce the tribovoltaic effect, which involves direct-current power generation through mechanical friction on semiconductor interfaces. This effect offers significant advantages in terms of high power density compared to traditional insulator-based triboelectric nanogenerators. Secondly, we elaborate on triboelectric modulation, which utilises the triboelectric potential on field-effect transistors. This approach enables active mechanosensation and nanoscale tactile perception. Additionally, we present triboelectric management, which aims to improve energy supply efficiency using semiconductor device technology. This strategy provides an effective microenergy solution for sensors and microsystems. For the interactions between triboelectricity and semiconductors, the research of tribotronics has exhibited the electronics of interfacial friction systems, and the triboelectric technology by electronics. This review demonstrates the promising prospects of tribotronics in the development of new functional devices and self-powered microsystems for intelligent manufacturing, robotic sensing, and the industrial Internet of Things.

A flexible tribotronic artificial synapse with bioinspired neurosensory behaviour was demonstrated, which establishes an active interaction mechanism with the environment.The device can well exhibit tuneable synaptic behaviours by changing the mechanical input modes, including excitatory postsynaptic current, paired-pulse facilitation, and the hierarchical memorial process.The device has excellent mechanical flexibility that can exhibit stable synaptic functions even under strain conditions with a bending radius of 20 mm after 1000 bending cycles.

Triboelectric nanogenerator (TENG) is a new energy technology based on interface contact electrification, in which the surface micro/nano-structures of triboelectric layers have great impacts on output performances. Here, we propose micro/nano-structures-enhanced triboelectric nanogenerators by femtosecond laser direct writing on both triboelectric layers. With a laser scanning ablation technology, the micro/nano dual-scale structures in stripes and cones are fabricated on Cu film surfaces, respectively. While the micro-bowls structure in different sizes are fabricated on polydimethylsiloxane (PDMS) surfaces by single pulse irradiation. Based on these prepared triboelectric layers, several kinds of TENGs in contact-separation mode are systematically characterized, in which the TENG with micro/nano-cones structure on Cu surface and micro-bowls structure on PDMS surface has the optimal performances and achieves about 21 times enhancement in power density. This work provides an effective femtosecond laser direct writing process for fabricating micro/nano-structures on both triboelectric layers and enhancing the output performances of TENG, which would greatly promote the practicality of TENG in mass manufacturing and micro-energy utilization.

Triboelectric nanogenerator (TENG) is a new energy technology that is as important as traditional electromagnetic generator (EMG) for converting mechanical energy into electricity, which shows great advantages of simple structure, high power density and low-frequency. Here, the effects of motion amplitude for both generators are first taken into consideration. Our result demonstrates that the TENG has a much better performance than that of the EMG at small amplitude. Under fixed operation frequency, the maximum output power of the TENG rapidly grows to saturation with the increase of the amplitude, while that of the EMG grows slowly and gradually. This contrastive characteristic is verified at different frequencies, which has demonstrated that the TENG has dominant scope over the EMG, in not only low-frequency but also small-amplitude. Moreover, electronics powered by the TENG in small-amplitude has been exhibited and an overall comparison of the TENG and EMG is summarized. Beyond low-frequency, this work has verified the small-amplitude is also a remarkable merit of the TENG for harvesting micro-mechanical energy, which has guided the development prospects of TENG as a foundation of the energy for the new era for internet of things, wearable electronics, robotics and artificial intelligence.

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/m2and 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.

Water wave energy is regarded as one of the most prospective renewable energy sources, while most of it has not been utilized for numerous technology defects. As a new energy technology, triboelectric nanogenerator (TENG) has been widely utilized for low frequency and random mechanical energy harvesting, which is very suitable for scavenging water wave energy. In this paper, we present a torus structured triboelectric nanogenerator (TS-TENG) which consists of an inner ball and a torus shell. Triggered by water waves, the ball revolves in the torus shell for triboelectric power generation, and the TS-TENG can harvest random wave energy from all directions. Moreover, to scavenge large-scale water wave energy, the TS-TENG array is fabricated and presented as a power source for persistently powering electronic devices and charging a battery or capacitor. With an agitation frequency of 2 Hz and an oscillation angle of 5°, the TS-TENG is expected to give a maximum peak power density of 0.21 W/m2. Take advantage of low-cost, environment-friendly and easy- implement, the development of the TS-TENG is of great significance for harvesting large-scale ocean wave energy and other potential applications in blue energy.

Triboelectric nanogenerator (TENG) has been developed as an effective way to harvest mechanical energy, which is expected for application in mechanical components. In this study, we report a kind of flexure hinges based triboelectric nanogenerator (FH-TENG) by 3D printing with great structural integration and stability. Based on the flexure hinges as a mechanical elastomer, the FH-TENG can convert mechanical energy into electricity by utilizing the contact electrification between fluorinated ethylene propylene and copper films. For a two-layer FH-TENG, it can deliver a maximal output voltage of 191 V and an instantaneous output power of 64μWon the external load of 210MΩat a frequency of 0.8 Hz and a force of ∼20 N. The output performances of the FH-TENGs with different layers, areas, minimum thicknesses and radii of the flexure hinges substrate are also systematically studied and discussed. Furthermore, as an alternative design, the FH-TENG has been integrated into a bearing pedestal, which can not only harvest mechanical energy from the shaft radial movement, but also be applied as a self-powered axis deviation sensor. This work has provided potential applications of the TENG for mechanical energy harvesting and self-powered damage monitoring in mechanical systems.

The physical filtration mechanism of a traditional face mask has a low removal efficiency of ultrafine particulates in the size range of 10–1000 nm, which are badly harmful to human health. Herein, a novel self-powered electrostatic adsorption face mask (SEA-FM) based on the poly(vinylidene fluoride) electrospun nanofiber film (PVDF-ESNF) and a triboelectric nanogenerator (TENG) driven by respiration (R-TENG) is developed. The ultrafine particulates are electrostatically adsorbed by the PVDF-ESNF, and the R-TENG can continually provide electrostatic charges in this adsorption process by respiration. On the basis of the R-TENG, the SEA-FM shows that the removal efficiency of coarse and fine particulates is higher than 99.2 wt % and the removal efficiency of ultrafine particulates is still as high as 86.9 wt % after continually wearing for 240 min and a 30-day interval. This work has proposed as a new method of wearable air filtration and may have great prospects in human health, self-powered electronics, and wearable devices.

Mechanical energy in a rolling tire is strong and stable, but it is always wasted and there is no effective means for harvesting. Herein, we demonstrate an array of compressible hexagonal-structured triboelectric nanogenerators (CH-TENGs) for harvesting the mechanical energy from a rolling tire. The CH-TENG units can be stacked in parallel connections and fixed in a rubber tire. The energy harvesting performances are systematically investigated and the maximum instantaneous power is 1.9 mW with the CH-TENG in 8 units, a weight load of 10 N and a speed of 2.51 m/s. The CH-TENGs have stable and durable characteristics for a 30-day continuous work and can drive a wireless tire pressure sensor once every 14 min when the moving speed is 2.51 m/s and weight load is 10 N. On the basis of the measured output power of the CH-TENG, it is expected to produce at least 1.2 W for a standard tire with the CH-TENG in 500 units and the running speed of 100 km/h. This work not only provides a promising solution to harvest the wasted mechanical energy from rolling tires, but also demonstrates the potential applications of the CH-TENG in sustainable automotive electronics.

Flexible electronics has attracted enormous interest in wearable electronics and human–machine interfacing. Here, a flexible organic tribotronic transistor (FOTT) without a top gate electrode has been demonstrated. The FOTT is fabricated on a flexible polyethylene terephthalate film using the p-type pentacene and poly(methyl methacrylate)/Cytop composites as the conductive channel and dielectric layer, respectively. The charge carriers can be modulated by the contact electrification between the dielectric layer and a mobile triboelectric layer. Based on the fabricated FOTT, pressure and magnetic sensors have been developed, respectively, that exhibit great sensitivity, fast response time, and excellent stability. The FOTT in this simple structure shows bright potentials of tribotronics in human–machine interaction, electronic skins, wearable electronics, intelligent sensing, and so on.

Effective power management has always been the difficulty and bottleneck for practicability of triboelectric nanogenerator (TENG). Here we propose a universal power management strategy for TENG by maximizing energy transfer, direct current (DC) buck conversion, and self-management mechanism. With the implemented power management module (PMM), about 85% energy can be autonomously released from the TENG and output as a steady and continuous DC voltage on the load resistance. The DC component and ripple have been systematically investigated with different circuit parameters. At a low frequency of 1Hz with the PMM, the matched impedance of the TENG has been converted from 35MΩ to 1MΩ at 80% efficiency, and the stored energy has been dramatically improved in charging a capacitor. The universality of this strategy has been greatly demonstrated by various TENGs with the PMM for harvesting human kinetic and environmental mechanical energy. The universal power management strategy for TENG is promising for a complete micro-energy solution in powering wearable electronics and industrial wireless networks. With the new coupling mode of triboelectricity and semiconductor in the PMM, the tribotronics has been extended and a new branch of power-tribotronics is proposed for manageable triboelectric power by electronics.

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.

Obtaining a wear-resistant, high-output, flexible direct current (DC) friction energy harvester is quite important for implementing self-powered portable electronic devices and Internet of Things (IoT). In this work, a direct current flexible textile organic tribovoltaic nanogenerator (FT-OTG) is reported, which is consisted of blended film of 11.11% poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT: PSS) and 88.89% polyvinyl alcohol (PVA), a hydrophilic conductive ink, a hydrophobic conductive textile and Al slider. The working mechanism of OTG is that after absorbing friction energy, abound electron-hole pairs are excited at the metal-semiconductor interface. These carriers move directionally under the joint drive of electrostatic field and the built-in electric field to form a current. After PVA doping, the output performance of DC-OTG, including open-circuit voltage and short-circuit current, is improved 5.6 times and 4.2 times, respectively. Furthermore, the mechanical properties of blended film, such as wear resistance, elongation and tensile strength, are improved, among which elongation at break is increased by 8 times and tensile strength increased by 3.2 times. By simplify series connecting, 3 FT-OTGs can constantly power portable electronics, like electronic watch, thermometer and calculator, respectively. This work provides an effective way for simultaneously enhanced output performance and mechanical properties of FT-OTG, which is expected to be a robust way for harvesting friction energy for self-powered electronics device and IoT sensors.

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.

Electrostatic manipulation of particles or droplets has raised huge interests across many fields including biomedical analysis, microchemistry and microfabrication/patterning, because of its merits of simple configuration and easy operation. However, traditionally applied bulky high voltage sources for electrostatic manipulation not only have potential safety risk to the operator and the devices, but also limit the portability. Here, we proposed an electrostatic microparticle manipulation system (EMMS) based on a triboelectric nanogenerator (TENG). Inspired from the pollen collection principle of honeybees, the EMMS featured a simple pin-to-plate electrodes system, which was electrostatically powered by the high voltage of the TENG. Different manipulation modes, including contact manipulation and noncontact manipulation were systematically studied. With a sliding displacement of 5 cm, the TENG delivered an output voltage of ± 3.2 kV, which could manipulate dielectric microparticles with weights of 1.7 mg, 0.9 mg and 13.3 mg at contact manipulation mode, noncontact manipulation (vertical lift) and noncontact manipulation (parallel move) mode, respectively. Manipulation mechanisms for both dielectric and conductive microparticles under different configurations of the pin-to-plate electrodes system were investigated. Finally, potential applications including micropatterning, dust remove and drug release/microchemistry were demonstrated to show the great prospects of the proposed TENG-based EMMS.

Vibrational triboelectric nanogenerators (V-TENG) can be used to harvest broadband vibration energy due to the nonlinear impact force induced by a stopper. However, V-TENGs with a single stopper have limited bandwidth and surface charge density, which has limited their application in wideband vibration energy harvesting. Herein, a V-TENG with two stoppers and a charge pumping effect is proposed for frequency band broadening and charge density enhancement. The theoretical analysis and experimental validation have indicated the V-TENG with two stoppers could improve the bandwidth by 75% compared with one stopper at a gap distance of 0.5 mm. Moreover, a charge pump can be constructed with two output channels, which has improved surface charge density by about 14 times. With the frequency varying from 18 to 38 Hz, the V-TENG can continually power 400 LEDs and charge a commercial capacitor quickly. This work has shown an encouraging method for enhancing the performance of V-TENGs, which also has great prospects in harvesting wideband vibration energy from machines, cars, ships, and human motions for self-powered electronics.

An attractive method to get a sustainable and green power source is to harvest energy from our living environment. However, most of devices for energy generation are fabricated by using bioincompatible materials, which limits their application in biomedical field. Here, we developed an arch-shaped biomedical triboelectric nanogenerator (TENG), which is fabricated by assembling two biocompatible polymer sheets made of materials having different triboelectric charactristics. The power generation mechanism and the electric output of the TENG, the thickness of the polymer sheet, and the style of lines loacated on the electrode were studied. The instantaneous output voltage and current density of the TENG can reach to 310.5 V and 16.2 μA, which can drive several commercial light-emitting diodes (LEDs). Additionally, we found that the appropriate thickness of the sheet and folding line’s design are both helpful to enhance the TENG’s performance. The survival rate of mouse L929 cells stimulated by TENG was significantly higher than that of the negative controlled test. Based on the TENG’s biomecical charateristic, such TENGs have the potential of harvesting energy from biological activities to drive biomedical devices possibly in vivo.

The textile-based triboelectric nanogenerator (tTENG) is one of the most promising energy harvesting devices for realizing self-powered smart textiles and wearable electronics. Herein, we report a scalable machine-knitting fabrication of stretchable, washable and breathable tTENGs for harvesting human motion energies. A plating stitch technique is employed to fabricate tTENGs using various common yarn materials and working in different modes (coplanar sliding mode and contact-separation mode). The tTENG can output voltage up to 232 V and power density up to 66.13 mW/m2. Furthermore, it can constantly power different wearable electronics by integrating with a small-size power management module, which converts the irregular AC output to a stable DC output and improves the energy utilization of tTENG. The stretchability, washability and air permeability of the tTENG are also demonstrated. These findings provide a practically viable textile-based power source that holds great promise in future self-powered wearable electronics and smart textiles.

Replacing the diseased joints with artificial prostheses has long been a common medical mean to alleviate pain or disability, in which the wear debris-induced aseptic loosening is the main mechanism for failure of artificial joint replacement. Timely and in situ detection of the wear debris is necessary to prevent further deterioration of the joint, and provides a basis for the lifetime diagnosis of artificial joint. Here, a self-powered sensor based on triboelectric nanogenerator (TENG) was developed for detecting wear debris generated in artificial joint. The TENG with polyethylene film and steel ball was designed into artificial joint configuration and fabricated by thermo-compression, which could in-situ detect the production of wear debris. Furthermore, the dependence of electrical output signals on the amount and size of the debris was investigated, which demonstrated obvious decrease in voltage with the increase in the amount and size of the particles. Finally, the fabricated sensor was tested in joint wear simulator, which achieved the real-time wear debris monitoring. This work expands the application of TENG in artificial joint wear detection, which is expected to promote the development of biomedical sensor and intelligent healthcare.

Triboelectric nanogenerator (TENG) has demonstrated huge potential in biomedical monitoring, robotic sensors, industrial environmental monitoring and so on. The harsh environment with different pH may have direct impacts on the performances of TENG. In this work, we systematically investigated the effects of interfacial acid-base on the performance of contact-separation mode TENG. The Fourier Transfer Infrared Spectroscopy (FTIR) exhibited the accelerating effect of acid-base on hydrolysis of polydimethylsiloxane (PDMS). Contact electrification on PDMS surfaces in macro and nanoscale both showed the increased charge densities with the increase of the H+and OH-concentration, respectively. X-ray photoelectron spectroscopy (XPS) and FTIR of the PDMS with different contact cycles indicated the heterolytic cleavage of the main chain upon contact, which can produce mechano radicals and induce electron transfer from SiO2to this lowest free molecular orbital (LUMO) of the PDMS naturally. More produced mechano radicals by cleavage induce more electron transfer, contributing to the increasing trend of contact electrification with ion concentration. These results have revealed the effect mechanism of acid-base on the polymer-based TENG’s performance, which can provide guidance for the development of polymer-based TENGs and self-powered smart sensors in harsh environment.

Micromechanical vibration, as one of the most prevalent forms of energy in an ambient environment, has surpassing application potentials as the power source for self-powered electronics. A triboelectric nanogenerator (TENG) can effectively convert vibrational energy to electricity, which has the unique benefit of a wide-band over a traditional vibration energy harvester due to the contact electrification mechanism. Herein, the frequency band characteristics of vibrational TENG (V-TENG) were systematically elaborated. The mechanical model of V-TENG was established to explore its working mechanism for wide-band vibrational energy harvesting. By simulation analysis and experimental validation, the bandwidth dependence of V-TENG on acceleration magnitude, proof mass, stiffness, and gap distance was investigated in detail. With optimized structural parameters, an ultra-wide-band vibration energy harvester (UVEH) was developed by a tandem spring–mass structure. Within the ultra-wide-band range from 3 to 45 Hz, the UVEH can invariably illuminate 36 serial light-emitting diodes (LEDs) and charge a 33 μF capacitor to 1.5 V within 35 s. This work has quantitatively studied frequency band characteristics of V-TENG and provided a promising strategy for wide-band vibrational energy harvesting from a machine, bridge, water wave, and human motion.

As the technology of the Internet of Things (IoT) develops, trillions of wireless nodes need to be powered. It's of significant importance to design self-powered systems by utilizing tirboelectric nanogenerators (TENG) to harness energy from environment. In this paper, a wind-driven self-powered wireless environmental sensing system is presented. A TENG working in the contact-separation mode with high output performance is designed and optimized to convert wind energy into electricity. Nine TENG units are then assembled into a 3D printed shell and demonstrated as a power source for two environmental monitoring systems. At a wind speed of 4.5 m/s, a Carbon monoxide (CO) monitor works sustainably and sends out a signal from 1.5 km away every 18 min, by using the radio transmission with 433 MHz ultrahigh frequency (Sub-1G). Another temperature and humidity hybrid sensor can send out the monitoring data every 9 min through Bluetooth (2.4 GHz) in a range of 50 m. Above all, this wind-driven self-powered system constructs a platform, which can be widely used in any other wireless remote environmental sensing scene, requiring sustainability and free of maintenance.

Smart sensor is the foundation and core of intelligent manufacturing, which is developing for miniaturization, integration and self-powering. Here, we report an active sensor array based on single-electrode triboelectric nanogenerators (TENGs) for dynamic wear monitoring and positioning. The sensor unit is fabricated by embedding the electrode into the core-shell composite with polytetrafluoroethylene (PTFE) as the core and polymethylmethacrylate (PMMA) as the shell. The working mechanism and performances of the sensor unit with different parameters including the thickness of PTFE@PMMA layer, reciprocating frequency, sliding displacement, electrode width and the diameter of copper bar are systematically investigated and discussed. By integrating into the sensor array, the dynamic wear monitoring and positioning have been realized, which can be used to detect the wear states of multiple regions in the sliding bearing system. This work has extended the application of the TENGs to determine the wear states of polymer interface and may promote the great development of intelligent bearing.