Liquid‐Metal‐Based Stretchable Triboelectric Nanogenerators for Flowing‐Liquid‐Based Energy Harvesting and Self‐Powered Sensor Applications

Abstract In this paper, a liquid‐metal‐based triboelectric nanogenerator (LM‐TENG) is proposed for harvesting energy from flowing water and self‐powered flow sensor applications. The proposed LM‐TENG mainly consists of a Galinstan working electrode that is encapsulated in a polydimethylsiloxane friction layer. The triboelectric performance of the LM‐TENG is optimized as a function of flow rate and frictional layer thickness. The output performance of the optimized LM‐TENG (6.2 V and 3.6 µA) is superior to that of the copper‐electrode‐based TENG (C‐TENG, 2.4 V and 0.8 µA) at the flow rate of 2.5 L min −1 . This is because the stretchability of the optimized LM‐TENG is three times higher than that of the C‐TENG, which increases the contact area and enhances the output performance. The optimized LM‐TENG is successfully demonstrated as a self‐powered flow sensor for remote monitoring of water flow in pipelines. In addition, the LM‐TENG is a capable of powering more than 30 LEDs and directly powering low‐power electronics (LCDs).