Sliding-mode Triboelectric Nanogenerator Research Articles

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.

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.

Super-Low Friction Electrification Achieved on Polytetrafluoroethylene Films-Based Triboelectric Nanogenerators Lubricated by Graphene-Doped Silicone Oil.

The novel proposal of Wang's triboelectric nanogenerator (TENG) has inspired extensive efforts to explore energy harvesting devices from the living environment for the upcoming low-carbon society. The inevitable friction and wear problems of the tribolayer materials become one of the biggest obstacles for attaining high-performance TENGs. To achieve super-low friction electrification of the TENGs, the tribological and electrical behaviors of the sliding-mode TENGs based on polytetrafluoroethylene (PTFE) films and metallic balls under both dry friction and liquid lubrication conditions were investigated by using a customized testing platform with a ball-on-flat configuration. Most interestingly, a super-low friction coefficient of 0.008 was achieved under graphene-doped silicone oil lubrication. The corresponding wear rate of the PTFE film was drastically decreased to 8.19 × 10-5 mm3/Nm. Simultaneously, the output short-circuit current and open-circuit voltage were enhanced by 6.8 times and 3.0 times, respectively, compared to the dry friction condition. The outstanding triboelectrical performances of the PTFE film when sliding against a steel ball are attributed to the synergistic lubricating effects of the silicone oil and the graphene nanosheets. The current research provides valuable insights into achieving the macro-scale superlubricity of the TENGs in practical industrial applications.

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

AbstractRotary 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.

Boosting Output Performance of Sliding Mode Triboelectric Nanogenerator by Shielding Layer and Shrouded-Tribo-Area Optimized Ternary Electrification Layered Architecture.

Sliding mode triboelectric nanogenerator (S-TENG) is effective for low-frequency mechanical energy harvesting owing to their more efficient mechanical energy extraction capability and easy packaging. Ternary electrification layered (TEL) architecture is proven useful for improving the output performance of S-TENG. However, the bottleneck of electric output is the air breakdown on the interface of tribo-layers, which seriously restricts its further improvement. Herein, a strategy is adopted by designing a shielding layer to prevent air breakdown on the central surface of tribo-layers. And the negative effects of air breakdown on the edge of sliding layer are averted by increasing the shrouded area of tribo-layers on slider. Output charge of this shielding-layer and shrouded-tribo-area optimized ternary electrification layered triboelectric nanogenerator (SS-TEL-TENG) achieves 3.59-fold enhancement of traditional S-TENG and 1.76-fold enhancement of TEL-TENG. Furthermore, even at a very low speed of 30rpm, output charge, current, and average power of the rotation-type SS-TEL-TENG reach 4.15 µC, 74.9µA, and 25.4mW (2.05W m-2 Hz-1 ), respectively. With such high-power output, 4248 LEDs can be lighted brightly by SS-TEL-TENG directly. The high-performance SS-TEL-TENG demonstrated in this work will have great applications for powering ubiquitous sensor network in the Internet of Things (IoT).

A speed-amplified tri-stable piezoelectric-electromagnetic-triboelectric hybrid energy harvester for low-frequency applications

This work proposes a new speed-amplified multi-stable tri-hybrid energy harvesting technique via the multi-stable nonlinearity enhanced frequency up-conversion and rack-pinion mechanisms to efficiently harness structural and biomechanical vibration energy. In the present design, two frequency up-conversion piezoelectric generators, an array-type electromagnetic generator and a sliding-mode triboelectric nanogenerator are integrated together to form a compact and interactive system. By utilizing the rack-pinion mechanism, the relative speed between the stators and the translators of the electromagnetic and triboelectric generators are both doubled. Meanwhile, the process of frequency up-conversion in the piezoelectric generators is also doubled per each cycle. This results in better performance under wideband and low-frequency vibration sources. For verification, a prototype of this design is tested by mechanical excitations and body-induced motions. In the shaker test, the prototype can generate a peak output power of 446.16 mW under an optimal resistance load, resulting in a normalized power density of 4.20 mW cm–3 g–2 at 5 Hz under 1 g. The prototype also exhibits exceptional performance under various human motion tests, it can drive 600 commercial light-emitting diodes simultaneously. Using a commercial DC/DC voltage regulator circuit, the proposed harvester can serve as a universal power source to charge commercial electronic devices, including smartphones and GPS sensors. The present design shows great potential as a sustainable power source for wearable/portable electronics as well as wireless monitoring systems.

Friction force excitation effect on the sliding-mode triboelectric nanogenerator

Triboelectric nanogenerator (TENG) is a promising energy harvesting technology. Clarifying the excitation effect of friction force on the sliding-mode TENG is important. In this work, three kinds of sliding-mode TENGs were fabricated and the short-circuit output current（Isc）was measured. The results show that the Isc of sliding-mode TENG under constant friction force improved with the increase of friction force, and a cyclic friction force dramatically excited the Isc. Moreover, it demonstrated that after a cyclic friction force excitation process, a small friction force was beneficial for electrical performance. The mechanism was discussed that the large friction force would result in the local friction heat temperature that has a great impact on friction interface electrons transfer and redistribution, therefore, a proper friction force is vitally important for improving the output performance rather than only increasing the friction force. These findings shed light on further understanding of the triboelectric behavior at the sliding friction interface.

Self-Powered Triboelectric Nanogenerator for Security Applications

Valuable jewels, documents, and files left in hotel rooms by guests can be stolen at any time by an unauthorized person. This could have a serious psychological and economic impact on the guests. The house/hotel owners should make efforts to prevent theft from occurring. In this study, a self-powered sliding-mode triboelectric nanogenerator (TENG) is used as a sensor on a drawer. It is fixed to the side of the drawer and works in the lateral sliding mode. The electricity generated by the device during the push-pull action of the draw is ~125 V and F~12.5 µA. An analysis of the electrical performance was carried out using PET, paper, and nitrile as sliding materials. The electrical output from the device is used to notify the guest or hotel owner of any theft by an unidentified individual via Arduino and node MCU devices. Finally, this device can be helpful at night and can be extended using different materials.

Mechanism and optimum pressure for sliding-mode nanogenerator

Abstract Triboelectric nanogenerator has extensive applicability because of its capability of harvesting mechanical energy and flexible working modes. To research the optimum pressure and improve the recovered energy of the sliding-mode triboelectric nanogenerator, a contact model of the Al/PTFE tribo-pair is studied by ab initio calculation and finite element simulation. The F-atom of PTFE is proved to be the electron accepter and the charges transferred can be predicted by Bader charge analysis. The mathematical relation between interfacial distance, charges transferred and contact pressure can be fitted. By Gauss’s law, the electric field is simulated and the regeneration energy of the sliding-mode triboelectric nanogenerator can be evaluated by the total electric energy and friction loss. Finally, an optimum pressure can be set to the upper or lower limit of working pressure corresponding to larger recovered energy. And less friction coefficient and larger contact area are also effective methods for recovering energy.

Triboelectric Nanogenerator-Based Vibration Energy Harvester Using Bio-Inspired Microparticles and Mechanical Motion Amplification

In this work, the novel design of a sliding mode TriboElectric Nano Generator (TENG)—which can utilize vibration amplitude of a few hundred microns to generate useful electric power—is proposed for the first time. Innovative design features include motion modification to amplify relative displacement of the TENG electrodes and use of biological material-based micron-sized powder at one of the electrodes to increase power output. The sliding mode TENG is designed and fabricated with use of polyurethane foam charged with the biological material micropowder and PolyTetraFluoroEthylene (PTFE) strips as the electrodes. Experimentations on the prototype within frequency range of 0.5–6 Hz ensured peak power density of 0.262 mW/m2, corresponding to the TENG electrode size. Further numerical simulation is performed with the theoretical model to investigate the influence of various design parameters on the electric power generated by the TENG. Lastly, application of the proposed TENG is demonstrated in a wearable device as an in-shoe sensor. Conceptual arrangement of the proposed in-shoe sensor is presented, and numerical simulations are performed to demonstrate that the real size application can deliver peak power density of 0.747 mW/m2 and TENG; the voltage will accurately represent foot vertical force for various foot force patterns.

Study on the triboelectric performance of porphyrin- and phthalocyanine-crosslinked enhanced fluorinated polyimide films for lateral sliding-mode triboelectric nanogenerator

• Two fluorinated polyimide films crosslinked by TAPP or TAPc were prepared. • The PI/TAPP and PI/TAPc films showed higher dielectric constant than neat PI. • The PI/TAPP and PI/TAPc exhibited smaller charge decay than neat PI in LS-TENGs. • The PI/TAPP and PI/TAPc showed higher friction coefficient stability than neat PI. In order to improve the charge retention, anti-decay ability and durability of traditional triboelectric materials in lateral sliding-mode triboelectric nanogenerators (LS-TENGs), two fluorinated polyimide films crosslinked by porphyrin tetra-amino phenyl porphyrin (TAPP) and tetra-amine phthalocyanine (TAPc) were synthesized, and their contact angles, dielectric properties, output performances and tribological properties were studied in detail. The results showed that the polyimide films crosslinked by TAPP (PI/TAPP) and TAPc (PI/TAPc) with lower surface energies had higher dielectric constants compared with neat PI and Kapton. In addition, TAPP and TAPc not only improved the electrical output with a small decay of charge density, but also reduced the wear of PI films during the whole triboelectrification process, which is attributed to the high permittivity and the crosslinked effect of PI with TAPP or TAPc. Thus, PI films with TAPP and TAPc hold great promise for dielectric research and LS-TENG applications.

Performance analysis and application of a hybrid electromagnetic-triboelectric nanogenerator for energy harvesting

In recent years, the possibility of harvesting the small-scale energies from the environment has been the subject of many scientific studies. Nanogenerators are emerging to be good candidates for converting the small-scale energies from the environment into electrical energy without need for battery. In this paper, a hybrid nanogenerator that integrates three different working mechanisms for conversion of mechanical energy into electrical energy is presented. The hybrid nanogenerator is composed of a zig-zag contact mode triboelectric nanogenerator (TENG), a sliding mode TENG and two electromagnetic generators (EMGs). Triboelectric surfaces are oppositely charged aluminium and Kapton layers for a zig-zag contact mode TENG and aluminium and PTFE layers for a sliding mode TENG. Aluminium layer is used as an electron donor, and also as an electrode. EMG unit is composed of two home-made copper coils and a neodymium magnet. All individual units are integrated into a two-piece acrylic shell. The whole device is of a compact, low-cost, and lightweight design. It has a size of 37 mm × 37 mm × 70 mm, which was optimized by modelling. Performance characterization verified the proposed hybrid nanogenerator as an efficient energy harvester. Output characteristics were tested under different loads (in a range from 10 kΩ to 100 MΩ). The maximum output voltage and current of the hybrid nanogenerator were estimated to be about 65 V and 15.25 μA, respectively. The maximum output power was 1.13 mW at 200 Ω. Charging performance analysis showed that the hybrid nanogenerator significantly enhanced the voltage level and charging speed of the tested capacitors in comparison with individual units. The hybrid nanogenerator charged 1μF capacitor to 9.1 V within 60 s. Individual units could simultaneously power at least 144 light-emitting diodes (LEDs). A hybrid signal could power at least 94 LEDs connected in series and at least 50 LEDs connected in parallel. Electrical energy produced by the hybrid nanogenerator was stored in a 47 μF capacitor bank and used to efficiently power a calculator.

Achieving High Power Density and Durability of Sliding Mode Triboelectric Nanogenerator by Double Charge Supplement Strategy

AbstractTriboelectric nanogenerators (TENGs), a promising energy harvesting technology for distributed power sources, faces inevitable issues regarding long‐term wear and durability. However, current low‐wear TENGs are impaired by lower performances due to low charge density. Here, both issues are addressed using a double charge supplement TENG (DCS‐TENG). Adding two low friction charge brushes allows the DCS‐TENG to achieve a high surface charge density (76.5 µC m−2) and power density (697.5 mW m−2 Hz–1), setting a new record among previously reported low‐wear TENGs. Moreover, the device exhibits unprecedented durability with an attenuation of only 5% after continuous operation for 110 h (3 960 000 cycles). Using a customized energy management module, a 3 × 7 hygrothermograph array, a high‐power vehicle's radar and accelerometer modules are stably powered, demonstrating the DCS‐TENG's strong electrical load capacity. This strategy provides a facile and effective path to conjointly boost power output and durability of TENGs, taking them to the next level for practical applications.

Capturing Dissipation Charge in Charge Space Accumulation Area for Enhancing Output Performance of Sliding Triboelectric Nanogenerator

AbstractThe charge space‐accumulation effect is one of most effective strategies to boost output performance of the sliding mode triboelectric nanogenerator (TENG) with AC output, by which the shielding layer greatly prevents the air breakdown on the sliding interface and the blank triboarea with charge dissipation on its surface promotes charge accumulation. However, charge dissipation speed depends on the properties of materials and these charges are lost in the air. Herein, a novel strategy is proposed to capture dissipation charge in charge space accumulation area for further enhancing output performance of the sliding TENG. DC output electrodes based on the coupling of triboelectrification and air‐breakdown is designed on both sides of the slider to quickly and completely collect the dissipation charge on the stator and accumulated charge on dielectric tribolayer of slider. Hence, the device has multichannel output to improve output charge to 98%. A new recorded average power density of 5.74 W m–2 Hz–1, 14 times higher than previously reported, is obtained. The coupling relationship between AC and DC output is systematically studied. This work provides a new idea for improving the output and energy harvesting efficiency of TENGs.

Output signals control of triboelectric nanogenerator with metal-dielectric-metal configuration through high resistance grounded systems

Toward a wide range of applications of triboelectric nanogenerator (TENG) as a power source, it is essential to develop a facile scheme to fabricate TENG with low output impedance by tuning the instantaneous output voltage without decreasing the output power. Here, we report a modified sliding-mode TENG, in which the flow of electrons between the grounded metal and the earth induces electric potential across a multilayered film consisting of dielectric/electrode/dielectric/electrode, confirmed by COMSOL simulation. By introducing a high-resistance grounding method through the ground, the electron flow is slowed down, thereby decreasing the impedance at the maximum output power from 3 MΩ to 0.6 MΩ with an enhanced output power by two-fold, explained in terms of reduced charge loss. The new-type of the device makes the charging speed to a capacitor (1 mF) faster by more than two-fold. Based on this result, the generated output power from the rotating-type TENG is supplied to an electrochemical water-splitting system for hydrogen production. Results demonstrate that the applied voltage required to reach 40 mA/cm2 is decreased to half of the initial voltage.

Hybrid enhancement effect of structural and material properties of the triboelectric generator on its performance in integrated energy harvester

A wind energy harvester (WEH) comprising a coaxial electromagnetic generator (EMG) and a triboelectric nanogenerator (TENG) is proposed to achieve an energy-autonomous closed loop that can harvest widely untapped energy sources for unattended monitoring systems in desolate regions. Energy conversion in the EMG from wind to electrical energy is implemented via the cyclic fixed-axis rotation, whereas that in the TENG is controlled by reciprocating translation driven by the coaxial rotation of the contact-separation structure. However, it is essential, albeit difficult, for TENG to generate a major portion of the wind energy-based electricity by improving the secondary transformation efficiency and reducing wear abrasion. Here, an arrayed contact-separation structure is fabricated with doped and surface-modified friction silicone rubber, large-area arc-shaped substrates, and a Reuleaux triangle plate-cam with local freedom. When the WEH works in one cycle, the TENG runs 12 times. Compared with the single contact-separation structure, the modified friction material significantly increases the output performance of the hybrid enhanced TENG by 104 % and the arrayed cam structure triples the output energy of TENG in a cycle. The maximum output power of the WEH is 54.78 mW at 90 rpm, to which the EMG and TENG contribute approximately 51.57 mW and 3.21 mW, respectively. The share of TENG output energy rivals the results induced by sliding mode TENG in those hybrid energy harvesters of current research. Furthermore, a WEH with an enhanced TENG is experimentally demonstrated by simulating earthquake, fire, and wind speed monitoring. The results indicate the immense potential of the proposed WEH in terms of power supply capability and long-term operation reliability.

A robust hybrid generator for harvesting vehicle suspension vibration energy from random road excitation

Existing energy harvesters are mostly designed into the electromagnetic shock absorbers to replace the original dampers in automotive suspension systems, possibly deteriorating sprung mass acceleration when the energy harvesters are in trouble. Therefore, this study proposed a hybrid generator based on the sliding-mode triboelectric nanogenerator (S-TENG) and electromagnetic generator (EMG) to harvest the suspension vibration energy without replacing the original damper and deteriorating sprung mass acceleration. First, the patterned polyimide (PI) films were prepared to solve the challenge of the poor durability of the S-TENG due to material wear. The results showed that the wear mass loss of PI film diminished with the decrease of pillar pitch, and the wear mass loss of P2 film was only 37% of that of the smooth one. Furthermore, whether the patterned surface could improve the electrical output of the S-TENG depended on the pattern parameters, which was a departure from the common view that any pattern could enhance triboelectrification. In this paper, P2 was the optimal textural parameter for improving the durability and electrical output of the S-TENG, which could provide a texture design reference for the S-TENG. Second, the hybrid generator charged a 4.7 μF capacitor to 18.05 V in 60 s, and the contribution ratio of charging voltage of the S-TENG component increased with extended charging time. Finally, the hybrid generator moved together with the original shock absorber without a noticeable impact on sprung mass acceleration, which can make the accelerometer self-powered at different random road excitations.

Ultrahigh Performance Triboelectric Nanogenerator Enabled by Charge Transmission in Interfacial Lubrication and Potential Decentralization Design.

Triboelectric nanogenerator (TENG) is a promising strategy for harvesting low frequency mechanical energy. However, the bottlenecks of limited electric output by air/dielectric breakdown and poor durability by material abrasion seriously restrict its further improvement. Herein, we propose a liquid lubrication promoted sliding mode TENG to address both issues. Liquid lubrication greatly reduces interface material abrasion, and its high breakdown strength and charge transmission effect further enhance device charge density. Besides, the potential decentralization design by the voltage balance bar effectively suppresses the dielectric breakdown. In this way, the average power density up to 87.26 W·m−2·Hz−1, energy conversion efficiency of 48%, and retention output of 90% after 500,000 operation cycles are achieved, which is the highest average power density and durability currently. Finally, a cell phone is charged to turn on by a palm-sized TENG device at 2 Hz within 25 s. This work has a significance for the commercialization of TENG-based self-powered systems.

Predicting output performance of triboelectric nanogenerators using deep learning model

With the development of artificial intelligence (AI), the use of AI algorithms for processing experimental data concerning engineering and physics has attracted broad attention, so the research of triboelectric nanogenerator (TENG) field can also adopt AI technology. Sometimes it is difficult and limited to analyze the impacts of structural parameters on output performance in physical experiments. The reason, on the one hand, is that TENGs structure changes in a small range, which makes the control of experiment difficult; on the other hand, is impossible to complete all the experimental parameters for verifying the experimental rules in the experiment. In this research, an AI algorithm model based upon deep neural networks (DNN) for TENGs is introduced for the first time to predict the output performance of TENGs under various structures and various conditions. The results show that the predicted output power values of the grating, disc, and rolling structures of the TENG by DNN model are consistent with the physical experimental data. Subsequently, we use the DNN model to predict the power output of TENG in the parameter range that the experiment has not tested in the grating, disc and rolling structure. Obviously, this will help researchers analyze the law of the data on a wider parameter range scale, so as to get a better experimental law. At the same time, by adopting the DNN model, we also predict the output performance of the sliding mode TENG under various load conditions.

Regulating the high-voltage and high-impedance characteristics of triboelectric nanogenerator toward practical self-powered sensors

In recent years, triboelectric nanogenerator (TENG), as a sensor with promising future, is expected to be widely used in many fields. However, the output of TENG has the characteristics of high voltage (> 10–100 V) and high impedance (in MΩ–GΩ), which hinder the TENG’s applications in sensor with considering the operation voltage of conventional electronic components. In this work, two front-end voltage signal processing circuit schemes are proposed, which can convert the high-impedance and high-voltage signal output from TENG into a low-voltage and low-impedance signal. First, we analyzed the circuit model by measuring the output voltage of the TENG sensor and explained the influence of the input impedance of the measuring device on the measurement accuracy. Then, we proposed two kinds of linear voltage signal processing methods which have been demonstrated the feasibility for a contact-separation mode TENG and a rotating type TENG. Finally, we applied the designed front-end signal processing circuit to a portable measurement system, which can measure the voltage signal up to 100 V output from a sliding mode TENG for local display or transmission to receiving terminal wirelessly. These two front-end voltage signal processing circuit solutions have the advantages of structure simplicities and cost-efficiency, and they can be used in combination with common electronic systems. The method can help with various practical TENG-based sensor applications and also provides an economical and simple solution for TENG voltage measurement. Two front-end voltage signal processing circuit schemes and linear voltage signal processing methods are proposed, which can convert the high-impedance and high-voltage signal output from TENG into a low-voltage and low-impedance signal. These two front-end voltage signal processing circuit solutions have the advantages of structure simplicities and cost-efficiency, and they can be used in combination with common electronic systems. The method can help with various practical TENG-based sensor applications and also provides an economical and simple solution for TENG voltage measurement. • Two regulating methods catering to the characteristics of high voltage and high impedance of TENG sensors were proposed. • A high-accuracy small signal circuit towards TENG was designed to replace specialized expensive measuring instruments. • An economical and exquisite solution for signal measurement is conducive to the practical application of TENG sensor.