Lightweight Triboelectric Nanogenerator for Energy Harvesting and Sensing Tiny Mechanical Motion

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.     

A Multi-Layer Stacked Triboelectric Nanogenerator Based on a Rotation-to-Translation Mechanism for Fluid Energy Harvesting and Environmental Protection

Energy shortage and environmental degradation are two important challenges facing humanity. Here, a multi-layer stacked triboelectric nanogenerator (MLS-TENG) based on a rotation-to-translation mechanism is reported for fluid energy harvesting and environmental protection. The mechanism transforms fluid-induced rotation into a reciprocal translation of the MLS-TENG, enabling the conversion of fluid energy into electrical energy. In addition, benefiting from a multi-layer stacked structural design, the open-circuit voltage is increased from 860 to 2410 V and an efficient energy harvesting rate of 2 mJ min⁻¹ is obtained in an actual river. Furthermore, with the assistance of the MLS-TENG, a self-powered wireless temperature and humidity monitoring system and a metal anticorrosion system are successfully established. Ambient monitoring data can be transmitted continuously at an interval of 49.7 s, and the corrosion rate of steel is significantly slowed down. This study provides guidance for efficient harvesting of ambient fluid energy, with promising applications in environmental monitoring and protection.     

High Durable Rotary Triboelectric Nanogenerator Enabled by Ferromagnetic Metal Particles as a Friction Material

Rotary sliding mode triboelectric nanogenerator (TENG) provides high efficiency, a continuous and high output strategy for harvesting low-frequency mechanical energy. However, poor durability owing to material abrasion during sliding restricts its practical application. Here, a novel ferromagnetic metal particle-based triboelectric nanogenerator (FMP-TENG) is proposed, which couples the unlimited point contact rolling motion of particles instead of planar contact of film to improve durability of TENG. Besides, due to the extensively enhanced contact area by ferromagnetic metal particles, FMP-TENG improves its electric output, achieving a charge density of 103 µC m⁻² and a peak power density of 400 mW m⁻² Hz⁻¹. After 10 000 cycle running-in, FMP-TENG exhibits excellent durability, which retains 97% of the output charge for 110 000 cycles. In addition, a metal powder mass sensor based on FMP-TENG is also designed, which can effectively detect mass change in ferromagnetic metal powder in a dynamic mechanical platform. A novel strategy is proposed here to solve the problem of durability of sliding TENG in practical applications.     

Harvesting Multidirectional Breeze Energy and Self-Powered Intelligent Fire Detection Systems Based on Triboelectric Nanogenerator and Fluid-Dynamic Modeling

Fire warning and monitoring are very important for public safety and environmental protection. However, most of the proposed wind energy conversion devices based on triboelectric nanogenerator (TENG) only work for unidirectional and high-speed wind and face the challenge of fatigue damage and even failure caused by cyclic stress. Moreover, TENG guided by the theory of fluid dynamics needs further exploration. Herein, a flow-induced vibration effect based TENG (F-TENG) for continuously capturing and monitoring multidirectional breeze (1.8–4.3 m s⁻¹) is developed to build a self-powered intelligent fire detection system (SIFDS). A dynamic model is proposed to study the intrinsic interaction between the electrical properties of F-TENG and wind. Since the model optimized F-TENG is more adaptable to wind characteristics, it delivers better performance and higher durability compared with previous studies. Relying on the dynamic model and combining the relationship between F-TENG's electrical output and wind characteristics, a self-powered visual wind sensing system is obtained. F-TENG successfully drives some electronic devices to monitor environmental information, which is expected to provide data for SIFDS to reduce fire hazards. This study can provide an in-depth understanding of the electromechanical conversion mechanism and large-scale capture and utilization of breeze energy.     

基于电流变效应的超精密工件台研究与展望

通过分析超精密工件台系统的研究现状和存在问题及电流变液ERF的机理和应用现状,提出"基于ERF半主动阻尼的直线电机驱动-气浮/磁浮导轨"纳米级超精密工件台系统.介绍了国内外相关研究,分析了此工件台系统具有的特性及尚待解决的问题.     

Multilayered Cylindrical Triboelectric Nanogenerator to Harvest Kinetic Energy of Tree Branches for Monitoring Environment Condition and Forest Fire

Forest fires present a great threat as they can rapidly grow and become large, resulting in tragic loss of life and property when occurring near occupied land. Here a self‐powered fire alarm system based on a novel multilayered cylindrical triboelectric nanogenerator (MC‐TENG) that can produce electrical power for the detection sensors by harvesting the kinetic energy of moving tree branches in a forest is presented. The major parameters for harvesting the kinetic energy using the proposed MC‐TENG are investigated, including the number of triboelectric layers, the frequency, the amplitude of external excitation, and the orientation between motion direction and device configuration. The fabricated MC‐TENG results in a peak power of 2.9 mW and a maximum average power of 1.2 mW at a low frequency of 1.25 Hz. The integrated self‐powered forest fire alarm system, consisting of fire sensors, a carbon‐based micro‐supercapacitor, and the MC‐TENG, is demonstrated to be able to report fire risk or hazard efficiently, accurately, and robustly. This study provides a new solution to reduce the forest fire risk through a portable and sustainable alarm system by effectively harvesting kinetic energies in natural environment with TENG technology.     

Flexible Sponge-Based Nanogenerator for Energy Harvesting from Land and Water Transportation

Triboelectric nanogenerator (TENG) devices with high robustness are promising in collecting powerful energy. In this study, highly elastic and pressure-resistance sponge fabricated TENG capable of adapting to high strength impact in land and water transportation and scalable for any shape is demonstrated for harvesting wave energy and mechanical energy. The polydimethylsiloxane sponge prepared by sacrificial template method has interconnected network and large size ratio of cavity-wall suitable for contact and separation. The operation modes of self-contact and extra-contact collaborating with MXene in electron transfer provide options for different operating conditions. The polydopamine-MXene modification of the sponge enables higher output due to the combination of the electronegativity, excellent adhesion, and antioxidant ability. Sponges are used to collect mechanical energy and applied for TENG-powered cathodic protection, making the 304 stainless steel (304 SS, Φ = 2 mm) electrode enter a thermodynamic stable state. What's more, the work also tries the universal strategies of program monitoring wave in the water tank and harvests the mechanical energy created by cars and passers-by, which enrich the applications of sponge TENG.     

Increase Output Energy and Operation Frequency of a Triboelectric Nanogenerator by Two Grounded Electrodes Approach

Triboelectric nanogenerator (TENG) generally operates using two‐electrodes to form a closed outer circuit loop without directly contacting ground. Here, a newly designed TENG, the two electrodes of which are grounded for doubling the energy output and the operation frequency, is introduced. The TENG operates in two modes: two‐channel mode in which the two electrodes are simultaneously connected to the ground, and single‐channel mode in which the two electrodes are alternately connected to the ground through a self‐triggered vibrating switch. Both modes doubles the total charges to be transported compared to the traditional ungrounded TENG. For the single‐channel TENG, about 30 current peaks with an output frequency of 50 Hz are generated in a single cycle at a motion triggering frequency of 2 Hz. The output energy at a load lower than 10 MΩ of the single‐channel TENG is enhanced, and the enhancing ratio is more than 100 at a load of 100 kΩ. The two electrodes grounded TENG provides a new strategy for effective use of the energy harvested from our living environment.     

Metal-Organic Framework Reinforced Highly Stretchable and Durable Conductive Hydrogel-Based Triboelectric Nanogenerator for Biomotion Sensing and Wearable Human-Machine Interfaces

Flexible triboelectric nanogenerators (TENGs) with multifunctional sensing capabilities offer an elegant solution to address the growing energy supply challenges for wearable smart electronics. Herein, a highly stretchable and durable electrode for wearable TENG is developed using ZIF-8 as a reinforcing nanofiller in a hydrogel with LiCl electrolyte. ZIF-8 nanocrystals improve the hydrogel's mechanical properties by forming hydrogen bonds with copolymer chains, resulting in 2.7 times greater stretchability than pure hydrogel. The hydrogel electrode is encapsulated by microstructured silicone layers that act as triboelectric materials and prevent water loss from the hydrogel. Optimized ZIF-8-based hydrogel electrodes enhance the output performance of TENG through the dynamic balance of electric double layers (EDLs) during contact electrification. Thus, the as-fabricated TENG delivers an excellent power density of 3.47 Wm^–2, which is 3.2 times higher than pure hydrogel-based TENG. The developed TENG can scavenge biomechanical energy even at subzero temperatures to power small electronics and serve as excellent self-powered pressure sensors for human-machine interfaces (HMIs). The nanocomposite hydrogel-based TENG can also function as a wearable biomotion sensor, detecting body movements with high sensitivity. This study demonstrates the significant potential of utilizing ZIF-8 reinforced hydrogel as an electrode for wearable TENGs in energy harvesting and sensor technology.     

Tunable Optical Modulator by Coupling a Triboelectric Nanogenerator and a Dielectric Elastomer

A conjunction system based on triboelectric nanogenerator (TENG) and dielectric elastomer actuator (DEA) is a promising demonstration for the application of TENG in the field of electronic skin and soft robotics. In this paper, a triboelectric tunable smart optical modulator (SOM) has been proposed based on this TENG‐DEA system. The SOM has a very simple structure of an elastomer film and electrodes made of dispersed silver nanowires. Owing to the voltage induced rippling of the elastomer, the output of the TENG for a contact‐separation motion at a velocity ranging from 0.5 to 10 cm s^?1 can decrease the SOM's transmittance from 72% to 40%, which is enough for realizing the function of privacy protection. Meanwhile, an effective operation method is also proposed for this SOM. By serially connecting an accessory DEA to the SOM, an external bias voltage can be applied on the SOM to tune its “threshold” voltage and the output from TENG can smoothly regulate the transmittance on the basis of the bias. The proposed operation method has excellent applicability for all DEA‐based devices, which can promote the practical study of TENG‐DEA system in the field of micro‐electro‐mechanical system and human–robots interaction.     

Template-Assisted Electrospun Ordered Hierarchical Microhump Arrays-Based Multifunctional Triboelectric Nanogenerator for Tactile Sensing and Animal Voice-Emotion Identification

The development of flexible and adaptable multifunctional sensing systems for human–machine interaction, especially for animal voice-emotion identification, is highly desirable yet quite challenging. Herein, a multifunctional triboelectric nanogenerator (TENG) based on ordered hierarchical microhump arrays is proposed and fabricated by template-assisted electrospinning with a facile, low-cost, and expandable manufacturing process. Performances of a single-electrode TENG based on the patterned nanofiber films with microhump arrays (NFM-TENG) are studied in detail by varying mesh number of the template. Electric field structure of the collector is altered by pore sizes, wire diameters, and protrusions of the receiving templates subjected to different mesh numbers, generating different degrees of microhump arrays on the surface of the nanofiber film. NFM-TENG demonstrates high sensitivity (15.94 mV Pa⁻¹), fast response and recovery time (76 and 58 ms), a large power density of 122 mW m⁻², and excellent ability of structural retention. Integrated with four functions of energy harvesting, pressure sensing, human physiological sensing, and animal voice-emotion identification, NFM-TENG achieves real-time monitoring of human physiological, motion, handwriting, and animal voice-emotion signals without an external power supply. This study shows significant application strategies for self-powered human–machine interaction devices, novel animal voice-emotion identification, biodiversity conservation, and so on.     

Remarkably Enhanced Charge Density of Inorganic Material Via Regulating Contact Barrier Difference and Charge Trapping for Triboelectric Nanogenerator

Currently, the research on improving charge density of charge-excitation triboelectric nanogenerators (CE-TENG) mainly focuses on surface modification and thinning of organic polymer materials. However, to increase durability and output, the exploration of high permittivity and high-thickness inorganic materials is important for extensive applications. Meanwhile, the physical mechanism of air ionization caused by air breakdown during secondary self-charge excitation (SSCE) needs to be explored. Herein, this study proposes a new strategy for CE-TENG based on inorganic materials by de-trapping reverse charge and increasing the contact barrier difference to obtain high charge density and achieve secondary self-charge excitation. SSCE of three types of films with different leakage currents are evaluated according to their trapping and de-trapping reverse charges. It is found that the trap distribution of dielectric films with larger leakage currents are mostly shallow-level traps, whose de-trapping ability becomes stronger after reverse charge injection. By regulating the contact barrier difference with thin organic polymer on thick inorganic high permittivity material, this study has achieved a high charge density of 1310 µC m⁻² with a fast start-up time of SSCE, which is a new record for the charge density of inorganic materials. This study promotes TENG of inorganic materials toward high-energy output applications.     

Cobalt-Nanoporous Carbon Functionalized Nanocomposite-Based Triboelectric Nanogenerator for Contactless and Sustainable Self-Powered Sensor Systems

Triboelectric nanogenerators (TENGs), which operate in contactless mode and avoid physical contact, are highly attractive for self-powered sensor systems aiming to achieve long-term reliable operation and reduce rubbing friction. Herein, an ultra-flexible and high-performance contactless double-layer TENG (CDL-TENG) is first designed and fabricated using a metal–organic framework-based cobalt nanoporous carbon (Co-NPC)/Ecoflex with MXene/Ecoflex nanocomposite layer for self-powered sensor applications. The porous structure of the Co-NPC provides a high-surface-area of the nanocomposite and the charge storage layer of the MXene/Ecoflex nanocomposite accumulates more negative charge to improve the functionality of the CDL-TENG two and three times, respectively. Compared with Ecoflex film-based TENGs, the fabricated CDL-TENG exhibits an eight-fold slower decay rate owing to charge trapping characteristics, which were confirmed by surface potential measurements. The CDL-TENG shows excellent humidity and acceleration sensitivity of about 0.3 V/% and 2.06 Vs² m⁻¹. The CDL-TENG also offers non-contact position detection performance in the 20 cm range. Furthermore, the CDL-TENG is successfully integrated with mobile-vehicles and an intelligent robot to perform obstacle and human-motion detection. Finally, a contactless door-lock password authentication system was demonstrated. These multifunctional benefits make it useful for numerous applications, including artificial intelligence, human-machine interfaces, and self-powered sensors.     

Self‐Powered Electrostatic Actuation Systems for Manipulating the Movement of both Microfluid and Solid Objects by Using Triboelectric Nanogenerator

By integrating a triboelectric nanogenerator (TENG) and an electrostatic actuation system (EAS), two kinds of self‐powered EAS are designed for manipulating the movement of both microfluid and tiny solid objects. The mechanical triggering of the TENG can generate an extremely high electrostatic field inside EAS and thus the tiny object (liquid or solid) in the EAS can be actuated by the Coulomb force. Accordingly, the tribomotion of TENG can be used as both the driving power and control signal for the EAS. The TENG device with a contact surface of 70 cm² can drive a water droplet to move across a gap of 2 cm. Meanwhile, the confluence of two droplets with the same charge polarity and different components can also be induced and controlled by this self‐powered EAS. In addition, based on the same working principle, this EAS also demonstrates its capability for manipulating solid object (e.g., a tiny steel pellet). By sliding the Kapton film along a segmented annular electrode, the tiny pellet can well follow the rotated motion of the Kapton film. The demonstrated concept of this self‐powered EAS has excellent applicability for various micro/miniature actuation devices, electromechanical systems, human–machine interaction, etc.     

Stimulating Acrylic Elastomers by a Triboelectric Nanogenerator – Toward Self‐Powered Electronic Skin and Artificial Muscle

Dielectric elastomers are a type of actuator materials that exhibit excellent performance as artificial muscles, but a high driving voltage is required for their operation. By using the amazingly high output voltage generated from a triboelectric nanogenerator (TENG), a thin film dielectric elastomer actuator (DEA) can be directly driven by the contact‐separation motion of TENG, demonstrating a self‐powered actuation system. A TENG with a tribo surface area of 100 cm² can induce an expansion strain of 14.5% for the DEA samples (electrode diameter of 0.6 cm) when the system works stably within the contact‐separation velocity ranging from 0.1 to 10 cm s^?1. Finally, two simple prototypes of an intelligent switch and a self‐powered clamper based on the TENG and DEA are demonstrated. These results prove that the dielectric elastomer is an ideal material to work together with TENG and thereby the fabricated actuation system can potentially be applied to the field of electronic skin and soft robotics.     

Achieving High-Efficiency Wind Energy Harvesting Triboelectric Nanogenerator by Coupling Soft Contact,Charge Space Accumulation,and Charge Dissipation Design

To enhance the durability of a triboelectric nanogenerator (TENG), soft contact is an effective approach due to its flexible and elastic contact mode. However, soft contact is hard to obtain with a large charge density by triboelectrification, resulting in low power output. Herein, a novel blade soft contact TENG (BSC-TENG), coupling flexible functional blades with shielded electrodes on the rotor, charge accumulation, and charge dissipation design on the stator, is proposed. Extra polishing blades and debris storage grooves are adopted in the BSC-TENG to further ensure high durability. A remarkable charge density of 328 µC m⁻² is achieved, setting a new record for soft contact TENGs. Besides, the output charge remains at 100% even after 200 000 cycles. The wind-driven BSC-TENG not only can power 3840 green LEDs and 80 parallel hygrothermometers but also can drive electronic devices for smart farms, establishing self-powered sensing systems. This work provides a novel strategy for enhancing soft contact TENG output and durability.     

A Universal Power Management Strategy Based on Novel Sound-Driven Triboelectric Nanogenerator and Its Fully Self-Powered Wireless System Applications

With the development of the Internet of Things (IoT), the power supply to trillions of IoT nodes has become a serious challenge. It is of significant importance to propose a rational power management scheme for constructing fully self-powered systems using triboelectric nanogenerators (TENG). In this study, as inspired by an embroidery hoop, a new type of TENG without the Helmholtz resonant cavity is developed for collecting sound energy, which can generate the V_oc and I_sc up to 500 V and 124 µA, respectively at a resonance frequency of 170 Hz and sound pressure of 110 dB. Furthermore, the sound-driven TENG integrated with a specially designed power management circuit derived from the universal power management strategy (PMS) can successfully drive a commercial narrow band-IoT wireless node, which realizes periodic temperature and humidity data acquisition and transmission. With the same strategy, an electric switch and a temperature and humidity acquisition system based on Bluetooth technology can also be powered by a contact-separated TENG and a wind-driven TENG, demonstrating excellent versatility, adaptability, and universality of the PMS. This study provides a novel solution for the application of TENG in the field of low-frequency IoT in local and wide areas.     

A Battery‐Less Arbitrary Motion Sensing System Using Magnetic Repulsion‐Based Self‐Powered Motion Sensors and Hybrid Nanogenerator

Self‐powered arbitrary motion sensors are in high demand in the field of autonomous controlled systems. In this work, a magnetic repulsion‐assisted self‐powered motion sensor is integrated with a hybrid nanogenerator (MRSMS–HNG) as a battery‐less arbitrary motion sensing system. The proposed device can efficiently detect the motion parameters of a moving object along any arbitrary direction and simultaneously convert low frequency (<5 Hz) vibrations into useful electricity. The MRSMS–HNG consists of a central magnet for the electromagnetic (EMG)–triboelectric (TENG) nanogenerator and four side magnets for motion sensors. Because all the magnets are aligned in the same magnetization direction, the repulsive force owing to the movement of the central magnet actuates the side magnets to achieve self‐powered arbitrary motion sensing. These self‐powered motion sensors exhibit a high sensitivity of 981.33 mV g^?1 under linear motion excitation and have a tilting angle sensitivity of 9.83 mV deg^?1. The proposed device can deliver peak powers of 27 mW and 56 µW from the EMG and TENG, respectively. By integrating the self‐powered motion sensors and hybrid nanogenerator on a single device, real‐time wireless transmission of motion sensor data to a smartphone is successfully demonstrated, thus realizing a battery‐less arbitrary motion‐sensing system for future autonomous control applications.     

An Intelligent Robotic System Capable of Sensing and Describing Objects Based on Bimodal,Self-Powered Flexible Sensors

This study presents an intelligent soft robotic system capable of perceiving, describing, and sorting objects based on their physical properties. This work introduces a bimodal self-powered flexible sensor (BSFS) based on the triboelectric nanogenerator and giant magnetoelastic effect. The BSFS features a simplified structure comprising a magnetoelastic conductive film and a packaged liquid metal coil. The BSFS can precisely detect and distinguish touchless and tactile models, with a response time of 10 ms. By seamlessly integrating the BSFSs into the soft fingers, this study realizes an anthropomorphic soft robotic hand with remarkable multimodal perception capabilities. The touchless signals provide valuable insights into object shape and material composition, while the tactile signals offer precise information regarding surface roughness. Utilizing a convolutional neural network (CNN), this study integrates all sensing information, resulting in an intelligent soft robotic system that accurately describes objects based on their physical properties, including materials, surface roughness, and shapes, with an accuracy rate of up to 97%. This study may lay a robotic foundation for the hardware of the general artificial intelligence with capacities to interpret and interact with the physical world, which also serves as an interface between artificial intelligence and soft robots.