Stretchable and Elastic Triboelectric Nanogenerator with Liquid-Metal Grid-Patterned Single Electrode for Wearable Energy-Harvesting Devices.

Abstract

Triboelectric nanogenerators (TENGs) have garnered significant attention as efficient energy-harvesting systems for sustainable energy sources in the field of self-powered wearable devices. Various conductive materials are used to build wearable devices, among which, gallium-based liquid metal (LM) is a preferred electrode owing to its fluidity and metallic conductivity even when strained. In this study, a stretchable, elastic, and wearable triboelectric nanogenerator is designed using a single electrode fabricated by embedding LM grid patterns into a stretchable silicone substrate through a two-step spray-coating process. Contrary to conventional double-electrode TENG that is challenging to integrate to human body, the LM grid-patterned single-electrode TENG (LMG-SETENG) has a simplified design and provides more flexibility. The LMG-SETENG can generate voltages of up to 100V via triboelectrification upon contact with the human body, even under various degrees of strain, owing to the fluidity of the LM electrode. The generated energy can be utilized as a sustainable energy source to power various small appliances. Moreover, the proposed LMG-SETENG can be utilized in soft robotics, electronic skin, and healthcare devices.