High-Electrification Performance and Mechanism of a Water–Solid Mode Triboelectric Nanogenerator

With the advantages of superior wear resistance, mechanical durability, and stability, the liquid–solid mode triboelectric nanogenerator (TENG) has been attracting much attention in the field of energy harvesting and self-powered sensors. However, most reports are primarily observational, and there still lacks a universal model of this kind of TENG. Here, an equivalent circuit model and corresponding governing equations of a water–solid mode TENG are developed, which could easily be extended to other types of liquid–solid mode TENGs. Based on the first-order lumped circuit theory, the full equivalent circuit model of water–solid mode TENG is modeled as a series connection of two capacitors and a water resistor. Accordingly, its output characteristics and critical influences are examined, to investigate the relevant physical mechanism behind them. Afterward, a three-dimensional water–solid TENG array constructed from many single-wire TENGs is fabricated, which can not only harvest tiny amounts of energy from any movement of water, but also can verify our theoretical predictions. The fundamentals of the water–solid mode TENG presented in this work could contribute to solving the problem of electrical phenomena on a liquid–solid interface, and may establish a sound basis for a thorough understanding of the liquid–solid mode TENG.