Figures‐of‐Merit for Rolling‐Friction‐Based Triboelectric Nanogenerators

Abstract

(1 of 10) 1600017 wileyonlinelibrary.com Adv. Mater. Technol. 2016, 1, 1600017 and freestanding mode, [15][16][17][18] the energy conversion effi ciency and device durability may be limited by the frictional resistive force between triboelectric surfaces, especially for the sliding-friction-based TENG. [19][20][21] Compared to in-plane sliding friction, rolling friction not only consumes less mechanical energy but also results in a higher robustness with minimized wearing of the materials. [ 21,22 ] In a previous work, a rolling triboelectric nanogenerator (RTENG) based on the rolling electrifi cation between cylindrical steel rods and planar thin fi lms of fl uorinated ethylene propylene (FEP) was reported, and a high energy conversion effi ciency of 55% was demonstrated, with a smaller surface wearing due to the low friction coeffi cient of the rolling movement. [ 21 ] Despite the unique merit of RTENGs, so far a systematic theoretical model to provide an in-depth understanding of their working principle is still lacking, and the issue of how to optimize their output performance remains to be studied.Recently, a standard method to quantitatively evaluate the performance of TENGs was proposed by Wang's group. [ 23 ] The performance fi gure-of-merit for TENGs was defi ned, consisting of a structural fi gure-of-merit (FOM S ), related to the structural design, and a material fi gure-of-merit (FOM M ), related to the square of the surface charge density. Hence, the performance FOM is directly proportional to the highest possible average output power and associated with the highest achievable energy conversion effi ciency, regardless of the mode and size of the TENG. Standards and evaluation methods would facilitate the comparison of various TENGs and lay the foundation for further applications of TENG technology. In the above-mentioned report, the structural FOM for various working modes was calculated using analytical formulae and fi nite-element simulations and it was found that the freestanding confi guration possesses the highest FOM S because of the lower capacitance between the electrodes. Besides the effect of the working mode, it should be possible for a certain working mode to explore the impact of structural design on the structural FOM, which was not included in the previous work, such as the electrode-gap effect for freestanding TENGs.In the present work, a theoretical model of rolling-frictionbased TENGs in a rolling, freestanding mode was constructed. The fi nite-element method (FEM) and theoretical equations were applied to reveal the fundamental physics and dynamic output characteristics of rolling TENGs for both Figures-of-Merit for Rolling-Friction-Based Triboelectric NanogeneratorsTao Jiang , Wei Tang , Xiangyu Chen , Chang Bao Han , Long Lin , Yunlong Zi , and Zhong Lin Wang * Triboelectric nanogenerators (TENGs) have emerged as a highly effective and easily scalable technology for harvesting mechanical energy. Recently, standards and fi gure-of-merits have been defi ned to quantify the pe...

A Self‐Powered Smart Roller‐Bearing Based on a Triboelectric Nanogenerator for Measurement of Rotation Movement

“…The output voltage with a resistance region from ≈100 to 10 8 Ω is shown in Figure S4 in the Supporting Information. This tendency of the output voltage increasing with higher external resistance was very similar to that of other TENGs and the theory of sliding‐mode TENG . Meanwhile, the output power of the smart bearing increased in the resistance region to 5 MΩ and then decreased under a larger load (>10 MΩ).…”

“…Here, by utilizing the mechanism of in‐plane charge separation working in a rotation mode, we demonstrate a triboelectric generator based on the structure of a roller‐bearing. The self‐powered roller‐bearing sensor is based on periodic contact between rollers and electrodes.…”

Large‐Scale Smart Carpet for Self‐Powered Fall Detection

“…[13][14][15][16][17][18][19][20][21] When two friction surfaces of TENG with different affinity contact under external force, Maxwell's displacement current will generate. [13][14][15][16][17][18][19][20][21] When two friction surfaces of TENG with different affinity contact under external force, Maxwell's displacement current will generate.…”

“…[13][14][15][16][17][18][19][20][21] When two friction surfaces of TENG with different affinity contact under external force, Maxwell's displacement current will generate. [18,23,24] Therefore, TENGs are also a kind of excellent self-powered sensor and can be used for detecting strain/force, motion trajectory, chemicals, sounds, etc. [18,23,24] Therefore, TENGs are also a kind of excellent self-powered sensor and can be used for detecting strain/force, motion trajectory, chemicals, sounds, etc.…”

Theoretical Study of Sliding‐Electrification‐Gated Tribotronic Transistors and Logic Device

“…[7,8] They can find important applications in artificial intelligence, human-machine interaction, and communication. [9,10] Recently, triboelectric nanogenerator (TENG) has emerged as a powerful technology for harvesting mechanical energy, [11][12][13][14] with three major applications in micro/nanopower source, self-powered sensors, and blue energy. [15][16][17][18][19][20][21] A new research field of tribotronics was then opened up in 2014, [22,23] using the electrostatic potential created by TENG as a "gate" voltage to tune/control chargecarrier transport in semiconductors.…”