Boost the Performance of Triboelectric Nanogenerators through Circuit Oscillation

Abstract

and sustainable energy. Triboelectric nanogenerator (TENG), as a novel mechanical energy harvesting technique invented by Wang et al., has proven to be an effective power alternative for small electronics and attracted plenty of interests in recent years. [4][5][6][7][8][9][10][11] To make TENG more practical and compatible to the commercial electronics, it is always desirable to improve the output performance. One way is from the device perspective, for example, choosing appropriate materials, designing the device structure, etc., [12][13][14][15][16][17][18][19][20][21] which is effective but needs specific optimization. The other one is from the power management perspective, [22][23][24][25][26][27][28][29][30][31] which is more general.Over the past few years, extensive efforts have been put into the power management of TENG for enhancing its output performance. [22][23][24][25][26][27][28][29][30][31][32] Zi et al. first proposed the concepts of "figure of merits" and "cycles for maximum energy output (CMEO)," [28] which provide the guideline for the maximum energy output per cycle of a TENG device. Afterward, Xi et al. [29] and Cheng et al. [30] have separately demonstrated the power management circuits which assist the TENG to achieve the 72% and 80% of the CMEO. However, the further approaching or even beyond the CMEO is more than difficult. Moreover, the maximum energy output can only be achieved when the load matches the impedance of TENG. Considering the low intrinsic capacitance of TENG and low frequency characteristics of the ambient vibration, the matching impedance is always beyond magnitude of tens or hundreds of megaohms. [15,33,34] Although several existing power management strategies can help reduce the matched impedance to several megaohms, [28,30] it is still much larger than the input resistance of common electronics, which are typically around hundreds of ohms. Recently, Qin et al. reported an interesting TENG system which can eliminate the requirement of impedance matching, [31] however, their system is only applicable for elaborate devices.Herein, in both theory and experimental verification, we report a novel power management strategy named oscillation assisting TENG (OA-TENG), which can exceed the CMEO limit of individual TENG under arbitrary load resistance. Unlike the previous power management strategies, the farther the load resistance from the matching impedance, the higher energy output per cycle can be provided from the OA-TENG, which means this strategy is especially suitable for the common electronics of low resistance. This OA-TENG is achieved by Triboelectric nanogenerator (TENG) which harvests ubiquitous ambient mechanical energy is a promising power source that can meet the distributed energy demand in the internet of things, wearable electronics, etc. However, the available output of TENG is severely limited by the saturated polarized charge density, small intrinsic capacitance, and large matching impedance. Herein, an effective power management strategy is proposed that fl...

Overview of Power Management for Triboelectric Nanogenerators

“…g) The V – Q curve for the oscillation‐assisting TENGs. Reproduced with permission . Copyright 2018, Wiley‐VCH.…”

“…Xu et al introduced the oscillating circuit to realize the flip of charge polarity on the conductive layer, the detailed working mechanism is shown in Figure e. When achieving the peak voltage of TENGs and closing the switch and the charge in the conductive layer reversed by the oscillating circuit, the voltage is also reversed, and then the switch is turned off.…”

A Review and Perspective for the Development of Triboelectric Nanogenerator (TENG)-Based Self-Powered Neuroprosthetics

“…The charge/energy accumulation/releasing by the switching operation is a universal method that helps to maximize the energy harvesting efficiency and enables a more sophisticated power management strategy. For example, based on the switching operation, a controlled LC oscillating circuit composed of a diode and inductor can help to further enhance the output energy and enable the impedance matching with low-impedance common electronics ( Figure 5 D) [ 70 ].…”

“…Reproduced with permission from [ 65 ]. Copyright 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim; ( C , D ) Power management methods based on the switchable TENG devices, ( C ) reproduced with permission from [ 69 ] and copyright 2017 Elsevier, and ( D ) reproduced with permission from [ 70 ] and copyright 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim; ( E1 , E2 ) Soft thin-film switchable TENG device used for physical sensing: ( E1 ) The layer structure of the soft thin-film switchable TENG device ( i ) and its typical output waveform by applying difference forces ( ii ); ( E2 ) The application for the physical sensing: ( i ) The physical operations can be decoded from the polarity (positive polarity refers to stretching/releasing and negative polarity refers to bending/pressing) and time constant (bending angle/force); ( ii ) The circuit configuration for the physical sensing; ( iii ) The bending angle decoded from the measured time constant; ( iv ) The application of bending angle and stepping force sensing when the TENG device is attached to the elbow and shoes; Reproduced with permission from [ 71 ]. Copyright 2020 Elsevier; ( F ) The Soft thin-film switchable TENG device connected with an inductor for wireless sensing and transmission.…”

Toward High‐Performance Triboelectric Nanogenerators by Engineering Interfaces at the Nanoscale: Looking into the Future Research Roadmap

“…However, this contact area has nanoscale interfaces that determine the final impact on the TENG’s properties. [ 12–38 ] The separation of these materials induces a dipole moment, which drives the charge (e.g., electrons) transfer by applying an external load onto the nanostructured interfaces of the two triboelectric materials. A TENG as a charge‐pump device could also provide current flow back and forth between the electrodes with a specific frequency to produce an alternating current (AC).…”