Liquid-Metal-Based\nSuper-Stretchable and Structure-Designable\nTriboelectric Nanogenerator for Wearable Electronics

Abstract

The\nrapid advancement of intelligent wearable electronics imposes\nthe emergent requirement for power sources that are deformable, compliant,\nand stretchable. Power sources with these characteristics are difficult\nand challenging to achieve. The use of liquid metals as electrodes\nmay provide a viable strategy to produce such power sources. In this\nwork, we propose a liquid-metal-based triboelectric nanogenerator\n(LM-TENG) by employing Galinstan as the electrode and silicone rubber\nas the triboelectric and encapsulation layer. The small Young’s\nmodulus of the liquid metal ensures the electrode remains continuously\nconductive under deformations, stretching to a strain as large as\n∼300%. The surface oxide layer of Galinstan effectively prevents\nthe liquid Galinstan electrode from further oxidization and permeation\ninto silicone rubber, yielding outstanding device stability. Operating\nin the single-electrode mode at 3 Hz, the LM-TENG with an area of\n6 × 3 cm² produces an open-circuit voltage of 354.5\nV, transferred short-circuit charge of 123.2 nC, short-circuit current\nof 15.6 μA, and average power density of 8.43 mW/m², which represent outstanding performance values for TENGs. Further,\nthe LM-TENG maintains stable performance under various deformations,\nsuch as stretching, folding, and twisting. LM-TENGs in different forms,\nsuch as bulk-shaped, bracelet-like, and textile-like, are all able\nto harvest mechanical energy from human walking, arm shaking, or hand\npatting to sustainably drive wearable electronic devices.