Single-electrode Triboelectric Nanogenerator Research Articles

Influence of Surface Functional Groups of ZnO Nanorods on the Performance of Cellulose Paper-Based Flexible Triboelectric Nanogenerator

We report on the fabrication of zinc oxide (ZnO) nanorod-based flexible, cost-effective single electrode triboelectric nanogenerator (STENG) on cellulose paper platform. In particular, the influence of surface functional groups of ZnO nanorods on the STENG output has been investigated. The STENG has been designed with chemically grown ZnO nanorod-coated paper as active triboelectric layer and Teflon/ Aluminum as counter triboelectric layer/ electrode. It has been found that post-annealing of nanorods at 125∘C improves the output voltage by twice compared to the pristine nanorods and delivers an output power of [Formula: see text]W/cm2. With annealing up to 125∘C, the optimal removal of the chemisorbed water from the defect sites of ZnO surface increases the intrinsic carrier concentration leading to maximum charge transfer and hence higher triboelectric output. On the other hand, a higher extent of oxygen accumulation from air at 150∘C lowers the intrinsic carrier concentration resulting in the reduced output. It has been proposed that the competition between the events like water removal and oxygen accumulation under different annealing temperatures can influence the STENG output largely. Finally, the optimized STENG has been demonstrated to work as wearable bio-mechanical sensors operating through bio-mechanical stimuli.

A skin-inspired, self-powered tactile sensor

Self-powered pressure- and temperature-sensing abilities are essential for the skin-inspired tactile perception ability of artificial electronic skins (e-skins). Recent research on e-skins has focused on simultaneous detection of pressure and temperature with a single device, whereas sensor operation without energy consumption remains a challenge. For genuine skin-like extrasensory perception, this study demonstrates a self-powered multifunctional ionic tactile sensor (SMITS) through lamination of a single-electrode triboelectric nanogenerator (SETENG) and a capacitive ionic sensor (CIS) sharing a common electrode. For this new type of electronic mechanoreceptor, a single touch not only enables identification of the kind of material but also electrifies the CIS, with the voltage varying under different pressures from 0 to 60 kPa and temperatures from 25° to 45°C without any additional energy supply.

Robust Hydrogel Adhesion by Harnessing Bioinspired Interfacial Mineralization.

Hydrogels have gained intensive interest in biomedical and flexible electronics, and adhesion of hydrogels to substrates or devices is indispensable in these application scenarios. Although numerous hydrogel adhesion strategies have been developed, it is still challenging to achieve a hydrogel with robust adhesion interface through a universal yet simple method. Here, a strategy for establishing strong interfacial adhesion between various hydrogels and a wide variety of substrates (i.e., soft hydrogels and rigid solids, including glass, aluminum, PET, nylon and PDMS) even under wet conditions, is reported. This strong interfacial adhesion is realized by constructing a bioinspired mineralized transition layer through ion diffusion and subsequent mineral deposition. This strategy is not only generally applicable to a broad range of substrates and ionic pairs, but also compatible with various fabrication approaches without compromising their interfacial robustnesses. This strategy is further demonstrated in the application of single-electrode triboelectric nanogenerators (TENG), where a robust interface between the hydrogel and elastomer layers is enabled to ensure a reliable signal generation andoutput.

Flexible single-electrode triboelectric nanogenerator with MWCNT/PDMS composite film for environmental energy harvesting and human motion monitoring

Flexible single-electrode triboelectric nanogenerator with MWCNT/PDMS composite film for environmental energy harvesting and human motion monitoring

Self-Powered Flexible Sensor Based on Triboelectric Nanogenerators for Noncontact Motion Sensing

Flexible sensors with surface suitability for complex-shaped objects generally sense object motion through a contact mode, which limits their application range and shortens their service life. The development of flexible sensors with noncontact working modes can overcome these shortcomings. Herein, superhydrophobic and self-powered flexible sensors based on a triboelectric nanogenerator (TENG) were fabricated by a step-by-step swelling-permeation method to prepare natural latex films with carbon black and silica nanoparticles embedded on their inner and outer surfaces, respectively. In addition to sensing object motion through contact, the TENG-based sensor can also sense charged object motion in noncontact mode based on the principle of electrostatic induction. The TENG-based sensor can sense horizontal and vertical movements of objects above it and can even detect the movement of objects with speeds as low as 0.04 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}/\text{s}$ </tex-math></inline-formula> . Interestingly, the sensor’s ability to monitor object motion in noncontact mode remains unchanged even at 70% strain. The TENG-based sensor can also be used to distinguish the type and amount of charge carried by an object and can harvest energy from moving objects in noncontact mode. Combining a single-electrode TENG with a freestanding TENG allows monitoring of the motion direction of an object loading an unknown type of charge in a noncontact mode. Based on the characteristics of our TENG-based flexible sensors to sense moving objects in both contact and noncontact modes, they have potential applications for human-machine interfaces, smart wearable devices, and flexible robots.

Wearable, freezing-tolerant, and self-powered electroluminescence system for long-term cold-resistant displays

Tremendous efforts in wearable optoelectronics have recently harnessed considerable advances in intrinsically stretchable electroluminescence (EL) devices. However, developing wearable optoelectronics that maintain long-term stability in harsh cold environments is still challenging. Here, a wearable, freezing-tolerant, and self-powered EL system is developed based on organohydrogel-based EL (OH-EL) device integrated with liquid electrolyte-based single-electrode triboelectric nanogenerator (LE-TENG), in which the OH-EL device based on self-healing and highly conductive organohydrogel electrodes can be directly lit by the LE-TENG. The stretchable OH-EL device demonstrates a bright and uniform light emission under 140% tension stretching as well as severe mechanical deformations of bending, rolling, and twisting. Moreover, the optical performances of the OH-EL device exhibit excellent repeatability and durability after continuous 2000 cycles. More importantly, bright blue-green light emission of the self-powered EL system stored at 253 K can maintain for six months, demonstrating extremely long-term freezing-tolerant capability. Furthermore, while harvesting the biomechanical energy of hand slapping and knee/elbow bending, the self-powered EL system worn on different parts of human body can achieve real-time visualized displays. Consequently, the simple fabrication and unique operation of the self-powered EL system demonstrate potential application in cold-resistant displays, wearable self-powered photoelectric devices, soft robotics, and other fields.

A high-performance, single-electrode and stretchable piezo-triboelectric hybrid patch for omnidirectional biomechanical energy harvesting and motion monitoring

Triboelectric nanogenerators (TENGs) have recently drawn much attention in the field of biomechanical energy harvesting and motion monitoring. However, the electrode stretchability and contact-separation model induced complicated packed structure remain a problem that heavily affects output performance during various human movements and requires to be urgently addressed. Here, a single-electrode piezo-triboelectric hybrid nanogenerator (SEP-TENG) integrated with stretchable liquid-metal metal electrodes is reported, which simultaneously achieves outstanding energy harvesting performance and skin-comfort human motion monitoring. A polarized piezoelectric BaTiO3/silicon rubber (SR) composites film is served as the effective negative tribomaterial, benefiting from the improved dielectric constant and piezoelectric charge transfer, the optimized SEP-TENG generates a high peak power density of 5.7 W/m2 while contacted with human skin. Besides, owing to the ultralow Young's modulus of the SR encapsulation layer and tribo-piezoelectric hybrid layer, the homogeneous integrated multilayer composite serves no break till a 745% elongation, promoting that the SEP-TENG could effectively harvest biomechanical energy and realize stable power supplying for wearable electronics even under large deformation state. Furthermore, the SEP-TENG could comfortably attach to the finger joints and collect bending energy. This work provides a novel design methodology for a single-electrode TENG to realize omnidirectional biomechanical energy harvesting and motion monitoring.

Multi-dimensional, transparent and foldable cellulose-based triboelectric nanogenerator for touching password recognition

Transparent power sources are required for emerging electronics and energy devices. However, most transparent materials/systems present certain problems: they are often fragile and unsuitable for shaping into fixed three-dimensional structures. Here, we attempted to overcome these challenges by constructing a cellulose-based multilayer film as a single-electrode triboelectric nanogenerator (TENG). The TENG was simply fabricated by the step-by-step deposition of a cellulose triboelectric layer, a silver nanowire electrode layer, and a protective cellulose layer. The tightly packed thin film is transparent, flexible and foldable. Four TENGs were spontaneously assembled into one film, and various spatial configurations were generated by a series of cutting and folding processes. We proved the practicality of a TENG-containing cellulose-based multilayer film by developing a multi-dimensional touch password switch, and expect that it will be widely used in film-based intelligent electronics.

Hierarchical nanofibrous mat via water-assisted electrospinning for self-powered ultrasensitive vibration sensors

Triboelectric nanogenerators (TENGs) have emerged as portable and self-powered sensors owing to its effective energy harvesting capability and rapid electrical responsive signals. Enlarging the contact area is an efficient way for improving output performance of TENGs. Nevertheless, few effective ways to fabricate high roughness nanofibrous mat have been reported. Herein, we report a facile and controllable water-assisted electrospinning approach to fabricate hierarchical morphology mats (HMMs) for self-powered sensor application. Driven by Marangoni flow, the electrospun nanofibers always move toward the center of existing nanofiber net on still water surface and pushing the net contract, the mat is thus formed toward the bottom and grow continuously. By changing the parameters of electrospinning processing, the forming and growth of HMM were tuned successfully, the surface patterning was realized through a designed drying process. The prepared HMM holds good mechanical property and high roughness. Single-electrode TENG (H-S-TENG) was then assembled by using HMMs, and it exhibits high output performance and good stability. On the basis of H-S-TENG, the developed self-powered ultrasensitive vibration sensor (SUVS) achieves precise detection of pulse waves from different arteries, and realizes the identification of recorded vibration spectrum from different strings of a guitar. This study provides a promising approach to fabricate electrospinning nanofibrous mat with tuned surface microstructure for high performance self-powered sensors.

Whey Protein Isolate Film and Laser-Ablated Textured PDMS-Based Single-Electrode Triboelectric Nanogenerator for Pressure-Sensor Application.

The use of biopolymers for realizing economical and eco-friendly triboelectric nanogenerators (TENGs) widens the application prospects of TENGs. Herein, an animal-sourced whey protein isolate (WPI) film, processed and prepared by a simple aqueous solution preparation and drop-casting technique, is applied to demonstrate its potential use in bio-TENGs. With the addition of formaldehyde in WPI, the films result in a free-standing and flexible film, whereas the pure WPI films are difficult to handle and lack flexibility. A TENG device based on the WPI and the laser-ablated textured polydimethylsiloxane (PDMS) for pressure-sensor application were developed. The output voltage of the TENG comprising WPI increased nearly two-fold compared to the TENG without WPI. A simple single-electrode TENG device configuration was adopted so that it could be easily integrated into a wearable electronic device. Moreover, WPI film exhibited tribo-negative-like material characteristics. This study provides new insights into the development of biocompatible and eco-friendly biopolymers for various electronic devices and sensors.

Liquid-solid triboelectric nanogenerators for a wide operation window based on slippery lubricant-infused surfaces (SLIPS)

Triboelectric nanogenerators (TENG) have emerged as suitable devices that are suitable to harvest widely abundant and renewable blue energy. However, a major drawback in related deployments include the reliability of the system when operating in variable atmospheric conditions. To address this limitation, we propose the integration of slippery lubricant-infused porous surfaces (SLIPS) as key TENG component. For instance, we combine SLIPS with transistor-inspired architectures to develop a robust single-electrode triboelectric nanogenerator (SLIPS-SE-TENG) that is shown to operate effectively under extreme temperature and humidity. For this purpose, we use the energy of water droplets (as in rain) impacting a surface to generate the electrical energy output. Our theoretical calculations and atomic force microscopy measurements show that a small volume of lubricant per surface area (4 μL/ per cm2 of porous PTFE) is sufficient to produce a low water contact angle hysteresis, leading to efficient energy conversion, provided the droplet’s moving velocity on the surface surpasses a threshold (0.3 mm/s). As such, we demonstrate SLIPS-SE-TENG to generate an instantaneous short-circuit current of 3 μA (charge density 8.8 nC/cm2). Importantly, we address the limitations of TENG fabricated with traditional superhydrophobic surfaces, affording a device that works normally and stably in harsh environments, under freezing temperatures or high humidity.

A large-area versatile textile for radiative warming and biomechanical energy harvesting

Both thermal management and electricity generation are becoming two basic functions for next-generation clothing integrated with wearable electronics. However, such versatile textiles with a simple design and great comfort have been rarely reported. Here, we propose a tri-layer textile that not only realizes solar and passive radiative warming but also harvests biomechanical energy to generate electricity. The textile is achieved by assembling photothermal nanoparticles on an infrared-reflective and conductive fabric with a tribo-negative polytetrafluoroethylene (PTFE) nanofiber membrane on the backside. The textile offers both a minimal thermal emissivity (down to 11.0%) and a maximum solar absorptivity (up to 83.7%), effectively suppressing radiation heat loss and boosting the harvested solar-thermal energy. Wearing such a textile enables a 3 °C drop of the indoor heating setpoint compared to a cotton textile, saving 25.2–100% of building energy consumption in ten cities worldwide. Moreover, the textile can serve as a single-electrode triboelectric nanogenerator. Remarkably high outputs (150–352 V, 7.5–27.8 μA) can be attained upon hand touching with different forces (14.7–44.0 N) and frequencies (0.9–3.9 Hz), which can power 41 LEDs. This textile opens a promising direction on how to develop a multifunctional energy-saving and electricity-generation textile while keeping thermal comfort for wearers.

Performance-Improved Highly Integrated Uniaxial Tristate Hybrid Nanogenerator for Sustainable Mechanical Energy Harvesting.

Despite advances in the development of individual nanogenerators, the level of output energy generation must be increased to meet the demands of commercial electronic systems and to broaden their scope of application. To harvest low-frequency ambient mechanical energy more efficiently, we proposed a highly integrated hybridized piezoelectric-triboelectric-electromagnetic (tristate) nanogenerator in a uniaxial structure. In its highly integrated approach, a piezoelectric nanogenerator (PENG) based on CsPbBr3 (cesium lead bromide) nanoparticles (NPs) and poly(dimethylsiloxane) (PDMS) nanocomposite was fabricated on a triboelectrically negative nanostructured polyimide (PI) substrate. A cylindrical aluminum electrode grooved with permanent magnets was directed to move along a spring-less metallic guide bounded by these nanocomposites, thus essentially forming two single-electrode mode triboelectric nanogenerators (TENGs). By its optimized material design and novel integration approach of the PENGs, TENGs, and electromagnetic generators (EMGs), this uniaxial tristate hybrid nanogenerator (UTHNG) can synergistically produce an instantaneous electrical power of 49 mW at low-frequency ambient vibration (5 Hz). The UTHNG has excellent charging characteristics, ramping up the output voltage of a 22 μF capacitor to 2.7 V in only 12 s, which is much faster than individual nanogenerators. This work will be a superior solution for harvesting low-frequency ambient energies by improving the performance of hybrid nanogenerators, potentially curtailing the technology gap for self-powered micro/nanosystems for the Internet of Things.

Dizajn i izrada triboelektričnog nanogeneratora sa spiralnom elektrodom i primena kao dinamički senzor nulte snage

Harvesting energy from environmental motions is an efficient method to prepare permanent power supplies for intelligent wireless systems. In this paper, a single spiral electrode triboelectric nanogenerator (TENG) is fabricated and investigated for energy harvesting from multi-directional sliding motions. The device is intended to be also used as a self-powered dynamic velocity sensor. In the first step, four samples are fabricated and characterized by applying 2 Hz sliding motions. The results show an increase in the output power from 1.53 to 20.72 nW, for a device with 4 to 20 turns. To compare the results, the effect of increasing the output power using a parallel array is also studied. In the next step, applications of the device as velocity and position sensors are investigated. A linear dependence between the input and output of the sensor is noticed for the device with 8, and 16 spiral turns. Finally, a circuit modeling for the device is presented, and a trend is suggested for the virtual capacitive behavior of the single electrode TENG.

Humidity-resistant, durable, wearable single-electrode triboelectric nanogenerator for mechanical energy harvesting

Humidity-resistant, durable, wearable single-electrode triboelectric nanogenerator for mechanical energy harvesting

Hydrogel‐based triboelectric nanogenerators: Properties, performance, and applications

The development of triboelectric nanogenerators (TENGs) in 2012 revolutionized the vision of environmental energy harvesting. Nowadays, TENG assembly, working mode, and material selection are investigated continuously in order to obtain high-performance and long-lasting devices. Hydrogels are flexible and stretchable water-swollen 3D polymer networks, which can be tailored to conduct electricity and render outstanding mechanical properties. Hydrogels have been used to develop novel flexible wearable TENGs. Here, we review the current knowledge concerning hydrogel-based TENGs, including an overview of relevant hydrogel characteristics, hydrogel-based TENG performance, and their practical applications. The single-electrode TENG working mode is the most popular in hydrogel-based TENGs as they can be easily attached and stretched for biomechanical energy harvesting. Hydrogel-based TENGs have demonstrated to be capable of delivering high electrical output (250-400 V, ≥10 μA) and being robust enough for devices that last for several months. Biomechanical energy sensing and harvesting, smart farming, biomedical, and human–machine control interfaces are investigated as potential applications of hydrogel-based TENGs. Interestingly, energy harvesting from human motion is of particular interest for this type of TENG due to its outstanding stretchability, strength, and additional physical properties, such as self-healing ability. In most cases, the devices are capable of powering small electronics entirely from harvested biomechanical energy. Biomedical applications involved wound healing acceleration driven by TENG-powered electrical stimuli and disease monitoring, including implantable devices. Despite showing promising electrical performance, controlling water evaporation is still challenging to maintain the mechanical and conductive properties of hydrogel-based TENGs. On the other hand, fully biodegradable TENGs are largely unexplored, as well as many applications, such as blue energy harvesting, the internet of things, and others. The next steps in this line of research must focus on addressing the main challenges of hydrogel-based TENGs and filling the application knowledge gaps.

Wearable Triboelectric Sensors with Self-Powered Energy: Multifunctional Laser-Engraved Electrets to Activate Satellite Communication for Life-Emergency Alert in Pandemics

Reliable sustainable power is inevitably a pillar resource for effective response to operate medical alert devices in pandemics. Only a few minutes of power outages can be a life-threatening event, especially for those who are vulnerable, such as bedridden patients and seniors with disabilities. This article addressed a self-powered wearable sensor that can send life-emergency requests instantly using satellite signals. The wearable sensor relied on a single-electrode triboelectric nanogenerator (SETENG) operated by a highly capacitive laser-engraved electret made of cuprite ions attached to graphene oxide [GO-Cu(II)] and coated on polytetrafluoroethylene. The multifunctional electret possessed the duality of negative triboelectric material and conductive GO-Cu(II) electrode that could generate self-power energy conversion when in contact with a positive triboelectric material of silk-Mg(II)–Ca(II). The voltage multiplier circuit (VMC) was integrated with the SETENG as an assistance unit to accelerate fast charge accumulation to capacitors, reaching 0.32 mC/m2 within a few minutes. Without the integration of VMC, SETENG itself exhibited intrinsically excellent stability and durability, obtaining a peak power density of 41 μW/cm2 and a high current density of 1.52 μA/cm2 under a loading force of 20 N. Besides, the electrical potential changes at different loading pressures on alphabetic electrets were further investigated using the finite element method. Hybrid quantum mechanics/molecular mechanics simulation revealed cationic ions on a finger bend electret segment via the translocation of cuprous ions in graphene voids. With the duality of high current density possessed by SETENG and the integrated VMC unit for fast charging, the SETENG wearable sensor can be self-powered using human finger pressures and can send a life-emergency signal via a satellite so the healthcare personnel can locate the person in distress and in need of immediate help.

Regulation of nanocrystals structure for high-performance magnetic triboelectric nanogenerator

Triboelectric nanogenerator (TENG) is a kind of capacitive conduction to convert mechanical triggering into electricity, which is the realized applications of Maxwell's equations in the field of nano energy and self-powered systems. As a conductor to participate electrostatic induction, the induction electrode has received little cognition. According to the unified theory of electromagnetics, the investigation of magnetic medium in TENG should not be ignored. Here we fabricate flexible single-electrode triboelectric nanogenerator (S-TENG) by the Micro Electromechanical System (MEMS) compatible technology, including non-destructive peeling technology and in-situ electrodeposition. Specifically, the S-TENG is composed of polydimethylsiloxane (PDMS) as the negative triboelectric layer and electrodeposited nickel as the induction electrode. Theoretically and experimentally, we demonstrate that ferromagnetic Ni electrode could substantially enhance the electrical output of TENG, which is attributed to the generated magnetizing current. The enhancement mechanism proposed in this work follows the law of energy conservation, which utilizes the natural magnetostatic energy inside the ferromagnetic medium and couples the working principle of TENG, thus making great contributions to the output of TENG. Furthermore, the relationship between the magnetic structure and performance is surveyed, and the stability of Ni and Ni-based S-TENG is also investigated. Finally, the proposed strategy for fabricating enhanced and stable Ni electrode is utilized in flexible energy harvester, and shows great prospects in flexible electronics. • The correlation between the micro magnetic structures and performance is investigated. • The magnetization effect in magnetic TENG is demonstrated. • MEMS technology is utilized to fabricate flexible and stable TENG.

A Flexible and Wearable Textile Electrode-Based Single Electrode Triboelectric Nanogenerator

Harvesting abundant mechanical energy is considered as one of the promising technologies for the development of autonomous self-powered power units, active sensors, and Internet-of-Things (IoT) devices [1]. Among various energy harvesting technologies, the triboelectric harvesters based on contact electrification have recently attracted much attention because of their advantages such as high performance, lightweight, and simple design [2]. However, obtaining a high-output performance is still of major concern for many applications.In this work, we proposed flexible and wearable triboelectric nanogenerators (TENG) where a highly conductive carbon cloth (CC) textile was utilized as an electrode and polydimethylsiloxane (PDMS) were used as an encapsulating triboelectric material to construct a single electrode mode TENGs. Further, sandpaper-assisted microtextures were developed on the PDMS surface via a simple soft-imprint lithography technique, and it was employed as a tribo-negative friction layer of TENGs. Moreover, to enhance the output performance of PDMS-based TENGs titania nanoparticles (NPs) were embedded as a function of weight ratio.As prepared wearable single-electrode-mode TENG devices can efficiently convert the mechanical energy into electricity while making continuous contacts/separations with counter tribo-positive friction objects. Fig. 1 shows the charging profile of a 1 µF capacitor by single-electrode TENG. These devices exhibited robust characteristics even after long-term cyclic operations and also generated an electrical output by gently touching with the human hand and were effectively employed as a power source to directly light 130 LEDs. Acknowledgments This work was supported by the research grants AP08052143 “Development of wearable self-charging power unit” from the Ministry of Education and Science of the Republic of Kazakhstan and 240919FD3914 “Self-Charging Rechargeable Lithium-ion Battery” from Nazarbayev University.

Bioinspired kinesthetic system for human-machine interaction

As the most basic and important sense of the human body, kinesthesia has the ability to act and adapt to stimuli. Simulating the kinesthetic process from the level of sensory neurons is an important task toward the emulation of neuromorphic computation, while currently report for artificial kinesthetic system is still not available. Hence, in this work, an artificial kinesthetic system is developed which consists of a single-electrode triboelectric nanogenerator (S-TENG) that can be attached to human skin and a field effect synaptic transistor (FEST). The S-TENG based on PDMS/MXene friction layer exhibits high sensitivity of 0.197 kPa−1 in a low-pressure region (<6 kPa) and 0.003 kPa−1 in a high-pressure region (6–30 kPa). FEST achieves synaptic plasticity in biology and simulates the short-term to long-term memory transition and learning process. Artificial kinesthetic system can readily achieve the perception of human muscle/joint motion state and orientation information. In addition, the assessment of fatigue driving risk is realized which substantially improves the efficiency and accuracy of the instruction recognition process. Furthermore, the identification of ASL (American Sign Language) gestures is simulated to demonstrate the recognition accuracy. This work shows a widespread potential in the construction of next-generation neuromorphic sensory network, neurorobotics and interactive artificial intelligence.