Mode Triboelectric Nanogenerator Research Articles

The Influence of Discontinuity‐Induced Fringing Effect on the Output Performance of Contact‐Separation Mode Triboelectric Nanogenerators: Experiment and Modeling Studies

Triboelectric nanogenerators (TENGs) are promising self‐powering supplies for various intelligent sensing and monitoring devices, especially because they can harvest electric energy from low frequency and small‐scale mechanical motions. Despite the fact that contact‐separation mode TENGs with smaller contact areas harvest higher electrical outputs due to fringing effect, the impact of fringing effect on TENGs’ electrical outputs is rarely investigated quantitatively. Herein, in this study, the influence of fringing effect on the electrical outputs of contact‐separation mode TENGs by introducing discontinuity on the tribo‐negative side manually is investigated. In the results, it is revealed that the TENGs with more discontinuities show higher overall electric performance. Compared to pristine TENGs, the TENGs with discontinuity increased significantly, improving the surface charge by 50% and the power density by 114% when cross discontinuities are applied. However, one should generate discontinuities on tribo‐negative side of TENGs using ceramic blade instead of metal blade within a positive‐ion atmosphere due to the neutralization through the electrically conductive metal blade. The computational simulation validates that the TENGs with discontinuities obtain higher electrical outputs, and further investigates the effect of discontinuity gap size and array distance on TENGs performance. In this study, a promising method is provided for the future design of TENGs using discontinuous structures.

Spontaneously established reverse electric field to enhance the performance of triboelectric nanogenerators via improving Coulombic efficiency

Mechanical energy harvesting using triboelectric nanogenerators is a highly desirable and sustainable method for the reliable power supply of widely distributed electronics in the new era; however, its practical viability is seriously challenged by the limited performance because of the inevitable side-discharge and low Coulombic-efficiency issues arising from electrostatic breakdown. Here, we report an important progress on these fundamental problems that the spontaneously established reverse electric field between the electrode and triboelectric layer can restrict the side-discharge problem in triboelectric nanogenerators. The demonstration employed by direct-current triboelectric nanogenerators leads to a high Coulombic efficiency (increased from 28.2% to 94.8%) and substantial enhancement of output power. More importantly, we demonstrate this strategy is universal for other mode triboelectric nanogenerators, and a record-high average power density of 6.15 W m−2 Hz−1 is realized. Furthermore, Coulombic efficiency is verified as a new figure-of-merit to quantitatively evaluate the practical performance of triboelectric nanogenerators.

Wave‐to‐Wire Model and Output Performance Analysis of a Point Absorption Wave Energy Converter Based on Triboelectric Nanogenerator

Herein, a point absorption wave energy converter (WEC) model combined with a contact–separation mode triboelectric nanogenerator (PAW TENG) is proposed. The model considers the interaction between the hydrodynamic forces captured by a point absorption conversion device of wave energy and the electrostatic force of the TENG. According to the established harmonic oscillation model of the buoy, the buoy's hydrodynamic properties and power generation characteristics are studied using finite element simulation and numerical simulation calculations. The best matching resistor circuit for PAW TENG in regular waves is investigated and analyzed. The electrical characteristics of the PAW TENG in the irregular wave spectrum are also solved. This work will provide design ideas for the experimental design of a novel point absorption WEC.

Liftoff of a soft-actuated micro-aerial-robot powered by triboelectric nanogenerators

Aerial insects can nimbly navigate in cluttered natural environments while they interact with delicate objects such as flowers and leaves. To achieve insect-like agility and robustness, power dense dielectric elastomer actuators (DEAs) have been developed for driving sub-gram micro-aerial-vehicles (MAVs). However, despite exhibiting muscle-like bandwidth and resilience, DEAs require a high driving voltage in the range of 1 – 2 kilovolts. This requirement poses substantial challenges for developing compact boost electronics and energy sources, which prohibit power autonomous operations of soft-actuated sub-gram MAVs. Here, we develop a compact and high power triboelectric nanogenerator (TENG) that can effectively charge a high-voltage DEA and enable the liftoff of a soft-actuated MAV. We propose an In-plane Charge Pump (ICP) design that can deliver over 1500 V and 110 mW without requiring a secondary charge pump or magnetic circuit components such as inductors or transformers. Compared to conventional free-standing mode TENGs, our ICP design shows a 280 % and 920 % increase in voltage and energy generation, respectively. When this TENG powers a DEA-driven MAV, the 160 mg robot achieves liftoff with a lift-to-weight ratio of 1.75. This result highlights the potential of powering high-voltage microrobots with energy-harvesting devices.

Effective parameters on polydimethylsiloxane/graphene composite-based triboelectric nanogenerator performance

ABSTRACT This paper systematically investigates the effective parameter on the performance of polydimethylsiloxane/graphene (PDMS@Gr)-based triboelectric nanogenerators (TENGs) as well as their applications. PDMS@Gr films containing 0, 0.05, 0.5, 1, and 1.5 wt.% graphene are synthesized, and their surface characteristics, mechanical behavior, and electrical properties are characterized. Vertical contact-separation mode TENGs are fabricated, and their performance is evaluated. The results demonstrate that the surface roughness and surface charge density are the most critical parameters for the performance of PDMS@Gr-based TENGs compared to the electrical and mechanical properties of the friction layers. The PDMS@Gr-based TENG with 1 wt.% graphene shows the highest power output of 2.6 W/m2 at an optimized working condition (5 Hz and 15 N). It also exhibits stable power output until 15,000 working cycles and displays battery-free applications by powering a light-emitting diode (LED) array, a calculator, a digital watch, and a digital thermometer.

Self-powered wireless flexible sensing for food storage based on triboelectric-electromagnetic generator

In Controlled Atmosphere (CA) food storage, maintaining optimal conditions, including gas concentration, temperature, and humidity on the food surface, is crucial. This paper proposes the application of a self-powered wireless flexible sensing system based on a triboelectric-electromagnetic generator in food CA storage. To configure certain concentrations of mixed CA gases, we need to accurately control the volume of CA gas input into the mixed gas tank within a certain period, and the gas flow velocity in the pipeline will directly affect this factor. The gas flow velocity in the pipeline is detected by the CA gas flow velocity detection part (FVS) with an independent layer working mode triboelectric nanogenerator (FV-TENG) as the main component. Simultaneously, a flexible Temperature and Humidity Sensor (THS) affixed to the food surface provides real-time monitoring. EMG collects irregular wind energy in the CA warehouse to provide energy for the processing of information in the system and wireless transmission to the IoT cloud platform, realizing the system's self-power and wireless transmission. The self-powered wireless sensing system facilitates remote collection of CA gas flow velocity data, precise control of mixed atmosphere gas concentrations, and real-time monitoring of food surface temperature and humidity in the CA warehouse.

Autonomous self-healing hybrid energy harvester based on the combination of triboelectric nanogenerator and quantum dot solar cell

Realization of multi-source energy harvesting with one single device would maximize power output. Thus, it is emerging as a promising strategy towards renewable energy generation and has attracted worldwide attention in the past decades. Capable of capturing mechanical energy that is ubiquitous in the ambient environment, triboelectric nanogenerator (TENG) has been considered a novel yet effective source towards next-generation energy harvesting. In this work, a flexible hybrid energy harvester (HEH) is developed via the rational integration of autonomous self-healing TENG and high bending-stable lead sulfide quantum dot (PbS QD) solar cell, enabling independent electricity generation by two different mechanisms. The single-electrode mode TENG component with self-healing is realized by a polydimethylsiloxane/Triton X-100 (PDMS/TX100) mixture as the dielectric layer and the shared gold (Au) electrode, which generates 0.39 µA of output current (Iout), 24.6 V of output voltages (Vout), 15.4 nC of transfer charges (Qsc), and 7.80 mW m−2 of output power peak density. The thin-film solar cell component is based on a PbS QD layer as the light absorber with a planar structure fabricated under low-cost and compatible conditions, achieving 22.8 mA cm−2 of short-circuit current density (Jsc) and 4.92% of power conversion efficiency (PCE). As a proof of concept, an electronic watch is successfully powered by harnessing ambient mechanical and solar energy with a hybridized energy cell. This approach will offer more opportunities to construct a versatile platform towards remote monitoring and smart home systems.

Polystyrene Waste-ZnO nanocomposite film for energy harvesting via hydrophobic triboelectric nanogenerator: Transforming waste into energy

This research aimed to generate electricity from polystyrene waste materials combined with zinc oxide (ZnO) nanomaterials. Developing alternative polystyrene waste materials for generating electricity in triboelectric nanogenerator (TENG) could be beneficial in a circular economy and sustainable development. With the motivation to reduce environmental pollution by using polystyrene waste, a recycled polystyrene-ZnO nanocomposite film (rPS-ZnO NF) was synthesized and served as a triboelectric material for energy harvesting applications. ZnO nanopowder was produced by a low-temperature solution immersion method in conjunction with a simple film-casting method to prepare the rPS-ZnO NF. The effects of varying amounts of toluene as a solvent medium and the immersion time in stearic acid (SA) solution treatment on the structural properties, wettability behavior, surface morphology, chemical bonding properties, surface characteristics, and TENG performance were investigated. In this work, rPS film, rPS-ZnO NF, and SA-treated rPS-ZnO NF were paired with Kapton film as the opposite triboelectric material in constructing the vertical contact-separation mode TENG. Compared to rPS TENG, the rPS-ZnO TENG exhibited a two-fold enhancement in performance (8.2 V) in output voltage and ∼4.5 fold enhancement (28.1 μW/cm2) in power density. Furthermore, following SA treatment, the triboelectric performance further improved, reaching the highest open circuit voltage of ∼8.8 V and the highest power density of 32.0 μW/cm2 for repeated 2 N-solenoid tapping force. The hydrophobic behavior was also improved with the highest water contact angle of 134.7 (when the SA treatment immersion time was 1 h). These findings demonstrate that SA-treated rPS-ZnO NF could be a promising candidate for efficient mechanical energy harvesting with high electrical output and excellent surface wettability. This research not only exhibits an excellent output performance of SA-treated rPS-ZnO TENG, but it also sheds new light on the sustainable approach of converting polystyrene waste into energy-harvesting material.

Design and development of a horizontal contact separated (HCS) test setup for measuring the performance of triboelectric nanogenerator for sustainable energy harvesting applications.

Triboelectric nanogenerators (TENGs) can play a pivotal role in harnessing non-utilized reciprocating motion and convert it into electrical energy that can later be stored in a battery or capacitor to power various Internet of Things-based smart electronic and wearable devices. Herein, we designed a cost-effective instrumental test bed focused on investigating the output performance of a horizontal contact separation mode triboelectric nanogenerator by varying the input parameters, such as applied force, motor speed, triboplate separation, and frequency of instrumental setup. The test bed mainly consists of three major parts: (i) application of force, (ii) tapping of TENG sample, and (iii) output parameters measurement. The output performance in terms of open circuit output voltage (VOC), short circuit current (ISC), and power density of polydimethylsiloxane-based TENG was monitored and optimized by varying the input parameters. A low-cost current measuring circuitry using an operational amplifier integrated circuit has been proposed with 92% accuracy. The maximum value of VOC and ISC was observed to be 254V and 31.8 µA at a motor speed of 600rpm, the distance between both the plates was 6mm, the input applied force of 40 N, and the striking frequency of 3Hz. The maximum power density of 2.1 W/m2 was obtained at an input impedance of 8 kΩ. The durability of the test bed as well as the TENG sample was also measured for 25h. The degree of uncertainty was measured for VOC, ISC, and applied force and calculated to be 1.62%, 7.45%, and 6.27%, respectively.

Formaldehyde degradation by soft-sliding-electrification-induced air ionization

Formaldehyde (HCHO), a highly toxic and carcinogenic gas, is the most common indoor air pollutant and a threat to human health. Developing simple and effective technological routes to achieve sustainable degradation of HCHO has become a common goal. In this work, we reported a self-powered air-ionized HCHO degradation system based on a soft-sliding freestanding mode triboelectric nanogenerator (SSF-TENG). The sliding-electrification process between soft rabbit fur and a robust PTFE film enables the generation of electrical outputs of up to ten thousand volts that can trigger air breakdown. The generated O3, ·OH and other highly oxidizing substances could degrade HCHO into CO2 and H2O. Through a standard ball gap platform based on two hollow Cu balls, the voltage of air discharge was measured to be between 11.2 kV and 14.4 kV. For demonstration, the SSF-TENG was applied to two parallel disk-shaped Cu electrodes to continuously breakdown the air with a peak discharge current of 6 mA. The system can produce a maximum O3 concentration of 1.2 ppm within 50 minutes. Moreover, the HCHO concentration can be reduced from 1.6 ppm to 0 within 20 minutes, and the degradation speed reaches 0.08 ppm/min. This work highlights the application of triboelectric microplasma in pollutant removal, which has great potential in self-powered environmental purification.

Regulating the electrical performance of contact-separation mode triboelectric nanogenerators based on double-sided groove textures

The contact-separation mode triboelectric nanogenerators (CS-TENGs) is a kind of micro/nano electromechanical power system based on the contact electrification and electrostatic induction. With the expansion of application field of the CS-TENG, regulating the electrical performance becomes essential. In this paper, simple and effective methods for the CS-TENG output regulation based on the double-sided groove textures are proposed. To do this, groove textures on both Cu contact electrode and PDMS dielectric layer are fabricated, and influences and mechanisms of the alignment angle (the angle between the direction of groove textures on the Cu electrode and that on the PDMS dielectric layer), matching condition (textures sidewall contact and non-contact) and applied pressure on the CS-TENG output are explored through output tests, contact and electrostatic simulations. It is shown that altering the alignment angle, matching condition and applied pressure of groove texture on the Cu contact electrode and PDMS dielectric layer, could simply regulate the output of CS-TENG, where changing the alignment angle is the most effective. Under low and high applied pressures, the variations of the output voltage with alignment angle from 0˚–90˚ reach to 343.8% and 297.2%, respectively, and CS-TENG at 0˚ angle outputs the maximum voltage under both pressures, while the minimum voltages under the two pressures are exhibited from different angles. The change of contact area induced by the longitudinal deformation and transverse expansion of the groove textures is the main reason for the output regulations.

Synthesis and characterization of zinc basic salt–loaded PVA-PEI polymeric composite for antimicrobial activity and triboelectric nanogenerator applications

There is a growing global demand for biodegradable, economical, and versatile materials. Accordingly, a novel material called zinc basic salt-loaded polyvinyl alcohol-polyethylene imine (ZBS@PVA-PEI) is introduced, which exhibits potential applications in antimicrobial, triboelectric, and energy harvesting. The film composed of ZBS@PVA-PEI demonstrated a significant inhibition zone against Escherichia coli (E. coli) strain during a modified agar diffusion antimicrobial test, after being in contact for 24 hours. Upon evaluation, it was observed that the material exhibited an inhibition zone ranging from 4.5–12 mm. This effect was attributed to the interaction between the positive surface charge of ZBS and the negative surface charge of the bacteria, and Zinc ion release. This study marks the first report on the utilization of ZBS as an agent for antimicrobial activity. Furthermore, the ZBS@PVA-PEI was assessed for its suitability in a single-electrode mode triboelectric nanogenerator (SE-TENG). A flexible film measuring 2.1 × 1.9 cm², consisting of ZBS@PVA-PEI, was utilized as positive triboelectric layer and generated approximately 230 V under a frequency of 5.6 Hz and a gap distance of 40 mm. Additionally, the TENG self-standing films were employed as keyboard covers, harnessing energy from typing and producing up to 13 V from conventional finger typing.

A multi-dimensional tactile perception system based on triboelectric sensors: Towards intelligent sorting without seeing

Tactile perception systems as the medium between the ambient environment and robotics lie in the heart of modern artificial intelligence. By providing different electronic readouts under various circumstances, they can give easily captured information for post-processing. However, for applications of most reported tactile perception systems, external location assistances are still needed. Here, as inspired by the platypus’ sixth sense, we developed a new kind of tactile perception system based on triboelectric sensors with the additional function from quantum rods. This terminal can be used as a single-electrode mode triboelectric nanogenerator for both location detection and vertical force sensing with high sensitivity and fast response. Moreover, by adding CdSe/CdS quantum rods into an imprinted polydimethylsiloxane film, different lateral stretching levels can be perceived by a modified luminescence. Supported by the machine learning technology, the as-fabricated tactile perception system finally obtains an excellent recognition accuracy among 18 different objects of 98.5% on a micro-controller unit platform, which provides an easy pathway in smart home robotics for intelligent sorting.

Electrohydrodynamic drying of pollens based on a dual-polarization induction mode triboelectric nanogenerator

Drying pollen and other powders are important procedures of the food industry. Here we demonstrate a self-powered cold plasma drying system for collecting and drying pollen powders based on a dual-charge-induction mode triboelectric nanogenerator (TENG). The charge accumulation strategy of TENG has been modified by a dual-polarized module, where both ultra-high voltage output (over 30 kV) and sufficient output charge density could be generated to enhance drying efficiency. Comparing with all the other direct-current TENGs with an output voltage over 15 kV, this as-fabricated TENG can provide the highest transferred charge density so far. The electrohydrodynamic forces generated by the high-voltage TENG can be used to evaporate moisture from pollen. Within 20 min, it can lower the moisture content of fresh pollen from 35% to 7%, presenting a straightforward design for storing pollen at present. As for the same electrohydrodynamic drying process, the energy consumption of this self-powered TENG-based drying system for evaporating 1 kg water is about 5.36 kJ, which is only 36.4% of energy consumption of commercial high-voltage power source. This design provides a simple yet effective low-power consumption drying system for current pollen storage, which can be a promising environment-friendly alternative for food industry.

Boron Minerals with Different Crystal Structures as Performance Manipulators in Triboelectric Nanogenerators

Triboelectric nanogenerators (TENGs) are energy generation devices that naturally convert mechanical movements into electrical energy through both triboelectric and electrostatic effects. The electricity generation capacity of silicone/boron minerals‐based composite and glass fiber‐based vertical contact separation mode TENGs enhances by adjusting the triboelectrification characteristics by embedding natural boron minerals (NBO) such as borax, colemanite, and ulexite additives. Considering the generated voltages, the NBO‐doped silicone and glass fiber‐based TENGs offer the maximum performance with 2.5 wt% borax, 7.5 wt% colemanite, and 5 wt% ulexite. The highest power density of corresponding NBO‐doped silicone glass fiber TENGs finds as 25.4, 26.03, and 32.03 W m−2, respectively. This work demonstrates that using boron significantly improves the TENG's power and charging capacities fabricated with silicone and glass fiber. Thus, the clean and safe generation of energy will contribute to the reduction of fossil fuel consumption and help protect the environment.

Orange peel-like triboelectric nanogenerators with multiscale micro-nano structure for energy harvesting and touch sensing applications

With the continuous advancements in technology, triboelectric nanogenerators (TENGs) have gained significant traction as efficient harnessers of low-frequency mechanical energy to meet the escalating energy demands. Notably, employing solid polymer electrolyte (SPE) as a contact layer or optimizing the microstructural composition of the surface material represents a prevalent strategy for augmenting the output performance of TENGs. However, the fabrication of numerous microstructures poses significant challenges, particularly in terms of incorporating environmentally harmful materials. Moreover, the utilization of triboelectric nanogenerators is further constrained by limitations associated with electrode materials. Although various techniques are available for producing transparent and stretchable electrodes for such generators, these procedures can be intricate and necessitate the use of hazardous chemicals. In this study, we exploit Poly(vinyl alcohol) (PVA) and natural bacterial cellulose (BC) nanofibers to fabricate contact layers with OP structures characterized by micron-scale domes and nanoscale microcracks. The electrodes were fabricated using BC hydrogel and ionic liquids(ILs). Under the action of hydrogen bond topological network, a multi-scale structure is formed comprising of a molecular-scale interlacing network of hydrogen bonds and a nanoscale fiber skeleton, which synergistically confer the ionic gel with remarkable tensile strength and high ionic conductivity (up to 83.51mS/cm). The resulting OP-TENG exhibited an output open-circuit voltage of 280 V, a short-circuit current of 24μA, and a maximum power density of 5.6 W m−2, enabling it to illuminate up to 303 LEDs. A SSEM-TENG was devised by stacking two single electrode mode TENGs on top of each other using a single wire. This innovative design holds great potential for applications in wearable motion monitoring, high-precision writing stroke recognition, and low-frequency mechanical energy harvesting.

A single-electrode mode triboelectric nanogenerator based on natural leaves for harvesting energy

This work reports a single-electrode mode triboelectric nanogenerator (G-TENG) based on natural leaf as the friction layer for application in the field of outdoor self-power supply.

Ultra-stability and high output performance of a sliding mode triboelectric nanogenerator achieved by an asymmetric electrode structure design

A new type of sliding-TENG with asymmetric electrode design achieves high output performance and ultra-stability by the balance of electrostatic shielding and charge accumulation for providing power supply to some electrical devices.

Highly Robust Self‐Switching Mode Triboelectric Nanogenerator Based on Misaligned Triple‐Cam Design

To enhance the robustness and lifespan of triboelectric nanogenerator (TENG) and facilitate its industrial applications, herein, a self‐switching mode TENG that combines the advantages of contact mode and noncontact mode TENG is presented. Noncontact mode TENG prevents material wear but generates insufficient power, whereas contact enhances power generation by increasing the charge density on the electrode surface. The proposed device can automatically switch between contact and noncontact modes through a triple‐cam mechanism and gear train deceleration mechanism. Experimental results determine the optimal force value of 6 N and corresponding cam height of 1 mm, contact time of 8 min, and noncontact time of 30 min, to ensure good power output and minimal material wear. Simulation results demonstrate that the three cams have more stable mechanical properties and can improve the device's robustness. The cam repose angle and gear train structure are optimized based on the curves of electrical output versus time for both modes, and a method is proposed to extend the self‐switching time. The self‐switching mode TENG has a longer life than the other two modes, with its transfer charge maintaining 90% of its initial value after 80 h of continuous operation.

Achieving Ultra‐Durability and High Output Performance of Triboelectric Nanogenerators

AbstractWith rapid development of the Internet of Things (IoTs) era, a variety of miniaturized and distributed electronics appear in every corner of industrial production and daily life. The shortage of fossil fuels requires renewable clean energy to replace traditional energy to meet the needs of smart and low‐power devices. Triboelectric nanogenerator (TENG) is a new technology for converting high‐entropy mechanical energy into electric energy to power these devices. However, improving the output energy and durability of TENG remains a considerable challenge for practical applications. To solve these problems and push forward its commercialization process, this paper systematically reviews how to improve the durability of the sliding mode TENG (S‐TENG) from the aspects of material optimization and structural design. Besides, a variety of ways are introduced to improve the electric output of the S‐TENG under the premise of high durability. At last, challenges and future research focus in this field are also predicted, which provide a guideline for the research of the high electric output and ultra‐durability TENG for highly efficient energy harvesting and self‐powered sensing applications in the IoTs.