Contact Electrification Behaviors of Solid–Liquid Interface: Regulation, Mechanisms, and Applications

Abstract

Liquid–solid contact electrification is a universal physical phenomenon. The electrical energy produced by a drop of water during the solid–liquid triboelectric electrification (TE) process is negligible, usually at the level of nA or uA. However, by adjusting the structure and composition of materials, or by designing devices more rationally, TE of a drop of water can reach voltages in the thousands of volts and currents in the mA level, which is sufficient to power many electronic devices. Therefore, studying solid–liquid triboelectric nanogenerators is of great significance in the field of energy harvesting. To achieve the manipulation of liquid–solid triboelectrification to nurture strengths and bypass weaknesses, a thorough knowledge of the liquid–solid contact electrification process and its influencing elements is required. The concept, influencing variables, mechanisms, and current control tactics of solid–liquid triboelectrification are addressed in this review. Then, using triboelectric generator technology, solid friction layers are designed and fabricated from three perspectives: structure design, surface functionalization modification, and interface wettability control, with discussion of how the three factors interact and contribute to solid–liquid electrification behavior. How solid–liquid triboelectrification can be used to capture energy and create self-powered sensors is discussed.