Triboelectric Research Articles

Wear-Resistant Smart Textiles Using Nylon-11 Triboelectric Yarns.

The ever-increasing demand for self-powered systems such as glucose biosensors and mixed reality devices has sparked significant interest in triboelectric generators, which hold large potential as renewable energy solutions. Our study explores new methods for integrating energy-harvesting capabilities into smart textiles by developing strong and efficient yarns that can convert mechanical energy into electrical energy through a triboelectric effect. Specifically, we focused on Nylon-11 (PA11), a material known for its crystalline structure well-suited for generating a powerful triboelectric response. To achieve this, we created triboelectric yarns by electrospinning PA11 fibers onto conductive carbon yarns, enabling energy-harvesting applications. Extensive testing demonstrated that these yarns possess exceptional durability, surpassing real-life usage requirements while experiencing minimal degradation. Additionally, we developed a prototype haptic device by interweaving tribopositive PA11 and tribonegative poly(vinylidene fluoride) (PVDF) triboelectric yarns. Our research has successfully yielded durable and efficient yarns with strong energy-harvesting capabilities, opening up possibilities for integrating smart textiles into practical scenarios. These technologies are promising steps to achieve greener and more reliable self-powered systems.

The Rise of Nanogenerators

The present article discusses the recent advancements in the field of self-powered systems that harness mechanical energy from vibrations in the environment to generate electrical power. It introduces the con-cept of nanogenerators, which can convert mechanical energy into electrical energy through piezoelectric or triboelectric effects. These nanogenerators are lightweight, flexible, and have a high energy den-sity, making them suitable for integration into portable electronic de-vices and wearables. The article also highlights their potential applica-tion as biomedical sensors for monitoring human health by capturing bio-mechanical stimuli such as heartbeat and pulse. The choice of ma-terials and device engineering are crucial in developing flexible and wearable nanogenerators, with various materials like semiconductors, transition metal dichalcogenides, and perovskites being explored for their piezoelectric and triboelectric properties. There is a need for fur-ther research to bring these technologies into everyday life, focusing on material selection, device engineering, and signal transmission tech-nology to advance energy harvesting and health monitoring systems.

The Rise of Nanogenerators

The present article discusses the recent advancements in the field of self-powered systems that harness mechanical energy from vibrations in the environment to generate electrical power. It introduces the con-cept of nanogenerators, which can convert mechanical energy into electrical energy through piezoelectric or triboelectric effects. These nanogenerators are lightweight, flexible, and have a high energy den-sity, making them suitable for integration into portable electronic de-vices and wearables. The article also highlights their potential applica-tion as biomedical sensors for monitoring human health by capturing bio-mechanical stimuli such as heartbeat and pulse. The choice of ma-terials and device engineering are crucial in developing flexible and wearable nanogenerators, with various materials like semiconductors, transition metal dichalcogenides, and perovskites being explored for their piezoelectric and triboelectric properties. There is a need for fur-ther research to bring these technologies into everyday life, focusing on material selection, device engineering, and signal transmission tech-nology to advance energy harvesting and health monitoring systems.

A flexible lightweight self-powered wireless metal detector enabled by triboelectric discharge effect

A flexible lightweight self-powered wireless metal detector enabled by triboelectric discharge effect

Enhanced tribocatalytic degradation performance of organic pollutants by Cu1.8S/CuCo2S4 p-n junction

Tribocatalysis research, leveraging the triboelectric effect, presents significant potential for environmental water pollution control. However, there is a notable scarcity of studies pertaining to tribocatalysis involving heterojunctions, particularly in the context of p-n junction tribocatalysis. In this study, we employed a one-step solvothermal method to synthesize a Cu1.8S/CuCo2S4 p-n junction composite catalyst. Subsequently, we explored the tribocatalytic degradation performance of organic pollutants facilitated by the Cu1.8S/CuCo2S4 catalyst. The findings reveal that, under simple magnetic stirring conditions, the degradation rates achieved by the Cu1.8S/CuCo2S4 catalyst for tetracycline (TC), methylene blue (MB), and methyl orange (MO) are remarkably high, reaching 99.9 %, 99.7 %, and 94.0 %, respectively. This underscores the broad applicability of the Cu1.8S/CuCo2S4 catalyst for the tribocatalytic degradation of diverse organic pollutants. Experimental evidence establishes that friction occurring between the polytetrafluoroethylene (PTFE) magnet rod, the beaker, and the catalyst induces charge transfer at their interfaces, generating highly oxidized active species that effectively decompose pollutants. Through free radical capture and electron spin resonance (ESR) tests, it was empirically determined and validated that the principal active species involved in tribocatalytic degradation are holes (h+) and superoxide radicals (O2–). Incorporating insights from the experimental characterization of p-n junctions and density functional theory (DFT) theoretical calculations, we propose a plausible tribocatalytic mechanism for Cu1.8S/CuCo2S4. This research not only contributes novel findings but also serves as a reference for the exploration of innovative heterojunction tribocatalysts.

Mechanically Robust and Electrically Stable High-Performance Triboelectric Nanogenerator Based on Fluffy-Free EC/Nylon-11 and PTFE/PVDF Nanofibers.

Electrospun nanofiber (NF)-based triboelectric nanogenerators (TENGs) have attracted significant attention in recent years due to their high specific surface area, flexibility, and facile fabrication. However, these TENGs' triboelectric (TE) layers composed of electrospun NFs fail easily due to the poor mechanical properties and fluffy characteristics of the NFs. Herein, electropositive and electronegative TE layers based on ethylcellulose-coated nylon-11 (EC/nylon-11) NFs and polytetrafluoroethylene-coated poly(vinylidene fluoride) (PTFE/PVDF) NFs are prepared via electrospinning and postcoating processes. The obtained EC/nylon-11 and PTFE/PVDF NFs are fluffy-free and exhibit 12.26 and 20.33-fold enhancements of Young's modulus compared with those of pure nylon-11 and PVDF NFs, respectively. The optimized TENG exhibits not only superior performance, including an open-circuit voltage (VOC) of 212 V, a short-circuit current (ISC) of 18.5 μA, and a maximum power density of 1.76 W/m2 but also excellent electrical durability for over 100,000 cycles. The TENG's capability is further demonstrated by continuously driving electronics for over 5 min and by being integrated into a self-powered sensor array of electric skin to detect different in vitro stimuli. This work provides an effective approach to obtaining mechanically robust and electrically stable NF-based high-performance TENGs, which may have potential applications in durable, wearable, and self-powered nanoelectronics.

Machine-learning-assisted wearable PVA/Acrylic fluorescent layer-based triboelectric sensor for motion, gait and individual recognition

Flexible sensors with precise perception ability play an important role in environmental sensing. The organic fusion between the sensitive structure and sensitive material presents some challenges for the overall design and integration of the sensor, including designing multiple sensitive branch structures, simplifying system design, and sensing multiple stress modes. Here, based on a same-plane interdigital electrode design, we developed a triboelectric sensor and its array (TSA) that mimics the synaptic structure of a neural cell. The interdigital electrode structure can effectively simulate the synaptic structure of neural cells and achieve effective perception of multi-directional stress. The enhancement of the triboelectric effect is achieved through layer-by-layer self-assembly technology between PVA film and acrylic fluorescent layer. The interface effect between PVA film and acrylic fluorescent layer can effectively enhance the electrostatic effect. Further analysis with deep learning CNN can extract higher-level motion features. A single sensor can be used to identify which part of the body is producing the movement (98.89%). A TSA with different numbers of sensors can achieve high-precision recognition of gesture numbers (99.25%), foot shape, gait (99.23%), and individuals (99.75%). The sensor can be flexibly manufactured and integrated according to specific application scenarios. The long-term goal is to effectively help limb-injured patients with rehabilitation therapy and build intelligent home environment.

A hybrid nanogenerator based on wind energy harvesting for powering self-driven sensing systems

The increase in energy demand makes it urgent to explore green energy sources. And wind energy is one of the most promising renewable energy sources. In this paper, a rotating hybrid nanogenerator with a combination of a direct-current triboelectric nanogenerator (DC-TENG) and an electromagnetic generator (EMG) is designed; the design concept is to harvest wind energy. First, an optimized ternary DC-TENG is designed based on the ternary dielectric triboelectrification effect. A soft contact structure is designed, which can effectively increase the frictional area as well as reduce the frictional resistance. Then, by introducing the EMG unit, the output power of the device and the speed of charging the capacitor are increased. The high output voltage of the DC-TENG and the high output current of the EMG complement each other to produce excellent power output. At 180 rpm/min, the output power of DC-TENG and EMG can reach 1.78 mW and 215 mW, respectively. With a simple power management circuit design, the device is successfully implemented to power small electronic devices. By charging a suitable capacitor, the device can be used as a power supply to power the sensor. Together with the sensor and power management circuit, it forms a self-powered sensing system that can drive the sensor for continuous operation. This work provides a simple, convenient, and reliable design that offers new insights into energy harvesting in nature.

Dual-mode sensor for intelligent solution monitoring: Enhancing sensitivity and recognition accuracy through capacitive and triboelectric sensing

Monitoring solution parameters is of utmost importance in various industries and daily applications. However, the challenge lies in using a single sensor to effectively monitor different parameters in the solution. In this study, a dual-mode sensor is proposed, capable of monitoring multiple solution parameters combined with deep learning method. The fabrication process of the dual-mode sensor is simple, involving a substrate, interdigital electrodes, and a dielectric layer. The sensitivity of the dual-mode sensor is improved by increasing the dielectric constant of the dielectric layer and optimizing the design of the interdigital electrodes. Under the capacitive sensing mode, the sensor effectively identifies solution type by detecting capacitance changes due to the conductivity of the mixed solution. Under the triboelectric sensing mode, the sensor exhibits high sensitivity to solution concentration through the coupling of the capacitive enhancement effect and the triboelectric effect. An electric switch is incorporated into the design to control the signal acquisition of the dual-mode sensor. By combining the deep learning method with the dual-mode sensor, high recognition accuracies have been achieved for both solution type and concentration, with average accuracies exceeding 95%. Furthermore, the dual-mode sensor is not limited to monitoring liquid droplets; it can also be used for monitoring the types of liquids in bottles. In addition, an intelligent system is developed to visualize the intelligent monitoring process. This work not only contributes to a better understanding of the underlying mechanisms of planar capacitive sensors (PCS) and free-standing triboelectric nanogenerators (FS-TENG), but also presents a promising method for intelligent solution monitoring.

Finite element analysis of a 3D triboelectric nanogenerator for biophysical health monitoring applications

The Triboelectric nanogenerator (TENG) has numerous applications in biophysical health monitoring due to its small size, lightweight, and economical use. The triboelectric effect occurs when two triboelectric materials with opposite polarities come into contact or rub against each other. This paper presents the simulated output performance of a three-dimensional TENG with two opposite dielectric circular layers separated by a distance of 0.05 μm. The bottom negative layer of polytetrafluoroethylene (PTFE) with a 0.5 μm diameter and 0.1 μm thickness has a negative aluminium electrode with the same dimensions. The top of the negative layer has cylindrical surface morphology. A layer of copper serves as both a positive layer and electrode with a diameter of 1 μm and a thickness of 0.1 μm. Furthermore, for analysis, PTFE is replaced by polyvinyl chloride (PVC) and polyethylene and the results are compared. The Finite Element Analysis (FEA) was used to analyze the geometry, employing a combination of Solid mechanics and Electrostatic module of COMSOL Multiphysics 5.6 software. The result shows that a maximum output voltage of 35.9 V was observed for an applied pulse pressure of 3 kPa as input. The results indicate that the TENGs have the potential to be used for various devices and wearable healthcare monitors.

Piezoionics: Mechanical‐to‐ionic transduction for sensing, biointerface, and energy harvesting

AbstractPiezoionic materials consisting of a polymer matrix and mobile ions can produce an electrical output upon an applied pressure inducing an ion concentration gradient. Distinct from charges generated by the piezoelectric or triboelectric effects, the use of generated mobile ions to carry a signal closely resembles many ionic biological processes. Due to this similarity to biology, the piezoionic effect has great potential to enable seamless integration with biological systems, which accelerates the advancement of medical devices and personalized medicine. In this review, a comprehensive description of the piezoionic mechanism, methods, and applications are presented, with the aim to facilitate a dialogue among relevant scientific communities. First, the piezoionic effect is briefly introduced, then the development of mechanistic understanding over time is surveyed. Next, different types of piezoionic materials are reviewed and methods to enhance the piezoionic output via materials properties, electrode interfaces, and device architectures are detailed. Finally, applications, challenges, and outlooks are provided. With its novel properties, piezoionics is expected to play a key role in the overcoming of grand challenges in the areas of sensing, biointerfaces, and energy harvesting.

All‐Weather Self‐Powered Intelligent Traffic Monitoring System Based on a Conjunction of Self‐Healable Piezoresistive Sensors and Triboelectric Nanogenerators

AbstractA self‐powered and sustainable traffic monitoring system is highly required for future urban development. Herein, self‐healable piezoresistive sensors and triboelectric nanogenerators (TENGs) are constructed by in situ polymerization of polyvinyl alcohol‐polyacrylamide double network hydrogel in the presence of sodium alginate and tannic acid‐modified cellulose nanocrystals (denoted as PPC) for all‐weather self‐powered intelligent traffic monitoring applications. Because of hydrogen bonding and boron ester bonding, the resultant PPC‐based strain sensor can rapidly self‐heal and restore its sensing ability within 1 min with a self‐healing efficiency of 97.4%. Based on piezoresistive effect, the ions in sodium alginate endow the PPC‐based strain sensor with a relatively high gauge factor of 8.39, which can monitor the motion and fatigue of drivers. Based on triboelectrification effect, the PPC‐based TENG sensor can detect instantaneous vehicle speed, judge traffic accident liability, evaluate vehicle weight, and alert the driver to prevent accidents caused by drowsy driving. After partially replacing water in the PPC with glycerin, the resulting PPC‐based TENG sensor exhibits stable performance at temperatures ranging from ‐30 to 40 °C, ensuring its all‐weather monitoring ability. The all‐weather and self‐powered intelligent traffic monitoring system is promising for ensuring the security of future cities.

Skin-Contact Triboelectric Nanogenerator for Energy Harvesting and Motion Sensing: Principles, Challenges, and Perspectives.

Energy harvesting has become an increasingly important field of research as the demand for portable and wearable devices continues to grow. Skin-contact triboelectric nanogenerator (TENG) technology has emerged as a promising solution for energy harvesting and motion sensing. This review paper provides a detailed overview of skin-contact TENG technology, covering its principles, challenges, and perspectives. The introduction begins by defining skin-contact TENG and explaining the importance of energy harvesting and motion sensing. The principles of skin-contact TENG are explored, including the triboelectric effect and the materials used for energy harvesting. The working mechanism of skin-contact TENG is also discussed. This study then moves onto the applications of skin-contact TENG, focusing on energy harvesting for wearable devices and motion sensing for healthcare monitoring. Furthermore, the integration of skin-contact TENG technology with other technologies is discussed to highlight its versatility. The challenges in skin-contact TENG technology are then highlighted, which include sensitivity to environmental factors, such as humidity and temperature, biocompatibility and safety concerns, and durability and reliability issues. This section of the paper provides a comprehensive evaluation of the technological limitations that must be considered when designing skin-contact TENGs. In the Perspectives and Future Directions section, this review paper highlights various advancements in materials and design, as well as the potential for commercialization. Additionally, the potential impact of skin-contact TENG technology on the energy and healthcare industries is discussed.

Energy harvesting techniques for sustainable underwater wireless communication networks: A review

The emergence of various underwater wireless communication systems has been on the rise due to increasing human activities in the marine environment. In underwater wireless communication networks (UWCNs), several communication devices, such as sensors and autonomous underwater vehicles (AUV) are interconnected to expand communication coverage, monitoring, information gathering, and surveillance. These devices operate on batteries, making their replacement and recharging difficult. Consequently, sustaining the operational lifetime of UWCNs is deemed a major challenge. This leads to the development of various energy harvesting (EH) techniques to perpetuate the power supply to underwater devices. In this paper, we present a review of various energy sources and EH techniques applicable to UWCNs. To achieve this, we classify the energy sources into various categories in order to establish the peculiarities of each source and the type of harvester applicable to each category. Based on this classification, we present discussions on various contributions of articles related to applications of EH techniques in UWCNs. In addition to various insights gained from the presented papers, we establish that energy harvesters based on triboelectric effect, piezoelectric effect, sediment microbial fuel cell, acoustic, and optical power transfer are suitable for low-power (milliwatt-order) consuming devices such as sensors. Also, for devices with high power consumption requirement, such as AUV, solar and inductive power transfer-based harvesters should be employed. Furthermore, we identify several technical challenges that should be taken into consideration during the planning and system design phases. Finally, we highlight open research areas that could further improve the EH and communication processes in UWCNs.

Corrugation-like Triboelectric Nanogenerators Integrated Buoys for Wave Energy Harvesting

Marine buoys, as the nodes of the marine monitoring system, play a vital role in monitoring marine activities, which can collect hydro-meteorological information for marine scientific research, offshore oil development, and construction of marine ports. However, sustainable and cost-effective power supply for marine buoys equipped with electrical devices is still a challenge. In this paper, the corrugation-like triboelectric nanogenerator (C-TENG) integrated with marine buoys was proposed, aiming at harvesting wave energy and powering marine buoys. The C-TENG consisting of corrugated plates, corrugation-like channels, aluminum electrodes, barrier sheets, flat plates, and polytetrafluoroethylene (PTFE) pellets, was capable of effectively converting the energy harnessed from waves into electricity. As a result of the ocean wave’s excitement, the sliding contact between the PTFE pellets and the aluminum electrode produced electron transfer via the triboelectrification effect and electrostatic induction. With the unique corrugation-like channels, the output of the devices was in the same phase, avoiding the electrical loss resulting from rectification. Furthermore, the power density of the 5 layers parallel-connected C-TENG units reached 21.95 W/m3, which was approximately 300% higher than the previous tower-like TENG. The experimental results prove that the proposed C-TENG may provide a possible solution for wave energy harvesting and marine buoy powering.

An Eco-Friendly and Dual-Functional Ag@BMO-Chitosan-Based Triboelectric Nanogenerator for Self-Powered Gas Sensing Application

Real-time monitoring of hazardous gases is critical to determine the influence of the air environment on the lives of people. Herein, a highly biodegradable chitosan-based triboelectric gas sensor has been successfully fabricated by using Ag@Bi2MoO6-Chitosan (Ag@BMO-CS) bilayer film obtained with the facile drop-casting method, which paired with polydimethylsiloxane (PDMS) film as triboelectric layers. The output voltage of the 5% Ag-modified chitosan bilayer-based triboelectric nanogenerator reaches up to 8.35 V at 2 Hz operating frequency. The integrated self-powered gas sensor based on the triboelectrification and gas adsorption effects shows the ability to distinguish ammonia (NH3) gas sensitively, and the response to 20 ppm NH3 (ΔV/Va = 59.1%) is 1.4 times larger than the separated self-powered sensor. In addition, the sensing mechanism combining the triboelectric effect and gas-sensing reaction was proposed to demonstrate the enhancement of NH3 sensing performance for Ag@BMO-CS-based triboelectric gas sensors. This work presents a sustainable self-supply gas sensor based on TENG for the detection of NH3 gas without any external power supply, which has a broad spectrum of applications in hazardous gas leaks, non-invasive diagnostics and fresh food transportation.

Highly Flexible Tribovoltaic Nanogenerator Based‐on P‐N Junction Interface: Comparative Study on Output Dependency Dominated by Photovoltaic Effect in Freestanding‐Mode

AbstractThe emergence of tribovoltaic nanogenerators (TVNGs) paves the way for developing a new kind of semiconductor‐based energy harvester that overcomes the restriction of low output current in a conventional approach. The traditional TVNG generally depends on the frictional pair between two rigid semiconductors (or metal‐semiconductor), limiting the practicability of flexible and portable electronics. Recent developments require the fundamental understanding of charge generation in diverse operating modes and structures. Here, a flexible TVNG based on the p‐Cu2O/n‐g‐C3N4 interface is presented. Operating in a freestanding mode, the proposed TVNG can generate a stable signal in any optical conditions including UV illumination, dark, and ambient. Under UV illumination, the electrical outputs of the TVNG reach 0.43 V and 2.1 µA cm−2, which are significantly larger than those obtained from dark and ambient conditions. The results demonstrate the coupling effect of three phenomena: tribovoltaic, photovoltaic, and triboelectric effects, and the unique mechanism to the observed signal is proposed. Additionally, the TVNG shows the practical feasibility of energy harvesting with capacitor charging and charge‐boosting circuits. This study showcases the unique concept with potential for developing a novel flexible nanogenerator in many aspects, including material, structure, and fundamental mechanism.

Degradation of organic dyes by utilizing CaCu3Ti4O12 (CCTO) nanoparticles via tribocatalysis process

Tribocatalysis is an emerging catalysis process which leverages the triboelectric effect, wherein the interaction between two dissimilar materials through friction yields charges capable of promoting diverse catalytic reactions. The current study utilized Calcium Copper Titanate, CaCu3Ti4O12 (CCTO) nanoparticles as a tribocatalyst to degrade a cationic organic dyes Methylene blue (MB) and Rhodamine Blue (RB). Tribocatalysis, a promising catalytic process, was conducted for a duration of 12 hours using a glass beaker and Polytetrafluoroethylene (PTFE)/Teflon. The degradation process was observed at different stirring speeds of Teflon, namely 300, 500, and 700 rpm for MB dye. The results indicated that as the stirring speed of Teflon increased, there was a corresponding increase in the degradation of MB dye. The maximum degradation achieved within the 12-hour was approximately 78% at a stirring speed of 700 rpm whereas approximately 60% of RB dye was degraded at same speed. Furthermore, stability of CCTO ceramic was maintained even after utilizing it for 4 consecutive cycles for both MB and RB dye. With the outcomes of the present study, it can be said CCTO nanoparticles possess the ability to harness mechanical energy from the surrounding, utilizing friction as a means to remove contaminants from water.

Harvesting and mapping ultrasonic vibration power using semiconducting wire-based tribovoltaic generators

Ultrasonic vibration is an excellent mechanical power source owing to its large power density. Harvesting ultrasonic vibrations has been demonstrated so far through piezoelectric effect, triboelectric effect, and electromagnetic induction. However, the majority of these devices only produce AC output which limits their potential applications. This work demonstrates, for the first time, the conversion of ultrasonic vibration power to DC output using semiconducting wire-based electric generators, in which one or several semiconductor wire/metal junction(s) are employed. A current density of up to 19 µA/cm2 and a peak power density of 5 µW/cm2 can be obtained under ultrasonic vibrations up to 37 kHz. The mapping of the ultrasonic vibrational strength has been achieved, demonstrating the capability of a self-driven powered ultrasonic sensor. The characteristics of individual semiconductor junctions and the series connection of several such junctions are studied using equivalent circuits.

Development of Label-Free Triboelectric Nanosensor as a Drug Screening Platform

Due to the emergence of new diseases, drug resistance and other factors, the discovery and development of new drugs has always been a very important issue in our life. However, discovering and developing new drug requires extensive pharmacological assessment, which is a complex, prolonged, highly expensive and risky process and takes about 10 to 15 years for the drug to be clinically approved. Recently, in order to improve the efficiency and accuracy of drug development, the researchers have been working on developing new drug screening platform. This research is dedicated to the development a label-free, rapid, easy operation and cost-efficient drug screening platform based on triboelectrification. Triboelectrification, also known as contact electrification, is the phenomenon which occurs when two interfaces come into contact and causes charge transfer between them. Recently, new technology with high development potential based on triboelectrification is called triboelectric nanogenerator (TENG), which can transfer mechanical energy into electrical energy. Moreover, TENG is developed as a self-powered sensor called as triboelectric nanosensor (TENS), which is coupling TENG and sensor. This work is the first drug screening platform of its kind based on triboelectrification. Recently, TENS have been developed for chemical sensing applications, in which the contact interface of TENG is functionalized with probe molecules with selectivity for different chemical analytes. After functionalization of the triboelectric contact layer, the rate of electron transfer induced by the triboelectric effect is different, result in the change in the electrical signal of TENG. When the contact interface is modified with target analyte, we observe a variation in the measured electrical output signal due to the amount of target on contact interface, thus demonstrating a self-power sensing process without any external power source. Here, we propose a new platform which when functionalized with protein, exhibits a variation in the electrical output signal with different concentration of drug. Furthermore, based on triboelectric effect, the as-prepared sensor was used to detect drug molecules with different binding affinities to the probe protein. The obtained results demonstrate a great potential for a highly sensitive drug screening platform.