Inverse thermoreversible methylcellulose-based and recyclable conductive gel for versatile triboelectric nanogenerator with rough interface under complex conditions

Recyclable methylcellulose (MC) gel-based versatile triboelectric nanogenerator (TENG) holds great potential in energy harvesting and multi-purpose sensing. However, forming difficulty, inverse thermoreversible sol–gel transition of MC, inferior electrical generation and sensing of TENG pose significant limitations on the widespread application of MC gel-based TENG in various complex environments. Herein, a novel sol–gel of MC and solvent replacement method is proposed to prepare MC/potassium hydroxide/glycerol (MKG) conductive gel with excellent strength, elongation and electrical conductivity based on hydrogen bonds and salting-out effect. To enhance interfacial contact, a simple glass template is used to fabricate MKG gel-based TENG with rough interface, which exhibits superior energy-harvesting capability and can power various electronic devices. As a versatile self-powered sensor, the TENG can monitor motion parameters of moving objects, human motions, as well as letter writing stably and sensitively. The power generation and self-powered sensing performances remain reliable and stable under complex conditions. Moreover, the prepared MKG gel can be recycled, and recycled MKG gel-based TENG that retains comparable electrical generation and multifunctional self-powered sensing to the original. This study provides new insights for designing high-performance inverse thermoreversible MC gel and versatile MC-based flexible electronics.