GaN-Based Solid–Liquid Triboelectric Nanogenerator in Single-Electrode Mode

Water resources, as an environmentally friendly and renewable energy source that does not emit greenhouse gases or other pollutants, have driven the development of triboelectric nanogenerators (TENGs) for liquid-based energy harvesting into a significant research and application trend. Compared to solid–solid TENGs, solid–liquid TENGs offer enhanced durability and stability by mitigating issues related to material wear and performance degradation. A single-electrode GaN-based solid–liquid triboelectric nanogenerator was designed to investigate the energy conversion mechanisms of droplet interactions with gallium nitride under different contact modes, including dripping, sliding, and jetting. The study systematically analyzed the effects of droplet motion mode, flow rate, volume, and surface inclination angle on the output performance of the GaN-based solid–liquid TENG. By adjusting the water flow rate, droplet volume, and salt solution concentration, we effectively optimized the output performance of the TENG. The GaN-based solid–liquid TENG utilizing a salt solution exhibited the highest output current, demonstrating the enhancement of charge separation due to the increased ion concentration in the droplets. Furthermore, rectification circuit experiments validated its capability to power low-power electronic devices such as LEDs and digital watches. This research provides a theoretical foundation for the application of GaN-based solid–liquid TENGs and the advancement of solid–liquid interface energy harvesting technologies.