Stretchable, self-healable, conductive and adhesive gel polymer electrolytes based on a deep eutectic solvent for all-climate flexible electrical double-layer capacitors

With the development of all-climate flexible/wearable supercapacitors, it is highly desired to prepare multifunctional gel polymer electrolytes (GPEs) with low-temperature tolerance. Herein, a GPE containing a deep eutectic solvent (DES), which is consisted of choline chloride and glycerol, is developed as the electrolyte of all-climate and flexible supercapacitors by in situ polymerization of acrylic acid monomers in the DES. The as-prepared DES-based GPE shows a room-temperature ionic conductivity of 3.33 mS cm−1, intrinsical adhesion, mechanical stretchability of 1000%, and quickly healable performance within 10 s. More significantly, the carbon-based supercapacitors assembled by using such a GPE have an areal specific capacitance of 101.3 mF cm−2 and all-climate stability from -20 to 80 °C. It also demonstrates a remarkable flexibility and an excellent self-healing capability. The presented work provides a facile and eco-friendly way to design GPEs for next-generation energy storage devices with high performance and all-climate tolerance.