Self-powered ionic tactile sensors

Abstract

Tremendous efforts have been devoted to wearable mechanical sensors to meet growing needs in healthcare sensors and electronic skins. Although self-powered sensors based on piezoelectric and triboelectric nanogenerators have been intensively investigated, self-powered ionic tactile sensors have been attaining increasing interest owing to their intrinsic deformability. Ionic materials used for the self-powered tactile sensors include hydrogels, iongels, restacked 2D nanosheet membranes, polymer composites, and ionic solutions. The mechanisms of self-powered signal generation can be divided into triboelectricity, ion migration, electrochemical reaction, thermovoltaic energy generation, and streaming potential generation. In this review, we address the ionic materials in each section, and discuss signal generation mechanisms corresponding to the ionic materials. The article ends with outlook and challenges in self-powered ionic tactile sensors.