Triboelectric nanogenerators comprising single-ion conducting materials : mechanisms and applications

Abstract

To solve worldwide energy and environment issues as well as to provide distributed and sustainable power sources for the future of the Internet of Things (IoT), triboelectric nanogenerators (TENGs) that can covert mechanical energy into electricity based on contact electrification (CE) and electrostatic induction is one of the most promising technologies. However, the fundamental mechanism of CE and the TENGs’ functionalization need to be studied for insight into better theoretical understanding and real applications. In this thesis, we investigated the mechanism of CE involving ion transfer and electron transfer in the fluorinated ethylene propylene (FEP)/ single-ion conducting material (SICM) pairs and the results show that higher humidity leads to more free ions and higher contribution of ion transfer in the total transferred charges. Furthermore, we developed a novel smart skin using SICM as the triboelectric layer that can sense static pressure and dynamic vibration by triboelectric effect and sense environmental humidity by hygroelectric effect. We also used machine learning to interpret the signals sensed by the smart skin and achieve high accuracy of sensation for different tactile modalities. Our research not only provides new insights into the mechanism of CE that involves ion transfer but also introduces a unique category of triboelectric materials that are single-ion conducting and demonstrates their unique potential applications in self-powered sensors for robotics, prosthetics, healthcare, and intelligent industry.