Stretchable, high ionic conductivity dual-network hydrogel-polymer electrolytes containing imidazole ionic liquids for supercapacitor and strain sensor

With the rapid development of smart devices and wearable electronic products, there is an increasing demand for flexible, durable, and high-performance energy storage systems. Supercapacitors (SCs) have become strong candidates for the next generation of energy solutions due to their excellent power density, rapid charge and discharge capabilities, and long cycle life. However, the limitations of existing electrolytes in terms of high ionic conductivity, mechanical strength, and stability under extreme conditions have restricted the development of SCs. This study has developed a new type of dual-network hydrogel-polymer electrolyte (DNHPE) based on polyvinyl alcohol (PVA), polyacrylamide (PAM), Lithium bistrifluoromethanesulfonimidate (LiTFSI), and 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF₄]), to enhance mechanical performance and ionic conductivity. The DNHPE-1 exhibits outstanding ionic conductivity (9.34 S m⁻¹), stretchability (650%), and thermal stability, which are crucial for the development of SCs and wearable sensors. In addition, the high strain sensitivity of the DNHPE-1 makes it an ideal material for strain sensors, capable of accurately monitoring various human movements. The research results show that the supercapacitor (SC) based on DNHPE-1 can operate effectively under different environmental conditions, demonstrating its broad application prospects in flexible, wearable smart devices.