Thermally Stable and Shape-Adaptive Triboelectric Nanogenerators Based on Liquid Electrolytes with Low Vapor Pressure

Aqueous solution-based liquid electrode triboelectric nanogenerators (TENGs) have attracted considerable interest in recent years due to their exceptional stretchability, deformability, and inherent shape-adaptability. However, previous aqueous solution-based TENGs face challenges related to drying, which may lead to operational failures. In this study, a low-vapor pressure liquid (LVPL) electrode TENG (LVPL-TENG) is presented that uses branched polyethyleneimine (bPEI) or deep eutectic solvent, choline chloride/glycerol (ChCl:Gly), to increase the stability of the TENGs at high temperatures. The LVPL-TENGs achieve a power density of ≈6.2 and 4.0 w m^-2 when using bPEI and ChCl:Gly as electrodes, respectively. Furthermore, these devices have remarkable energy harvesting capabilities while being stretched up to 400%. Importantly, the LVPL-TENGs maintain a constant electrical output after being stored at 100 °C for 24 h. Utilizing a simple single-electrode design, the LVPL-TENGs can efficiently harvest various small physiological movements, i.e., finger bending, grasping a coffee cup, or clicking a computer mouse. Additionally, the LVPL-TENGs have the potential to function as self-powered tactile sensors to detect the touch of any material object, indicating promising applications in the realm of human-machine interaction. This study opens new avenues for deploying stretchable and shape-adaptable TENGs operating at high temperatures.