A renewable hydrogel electrolyte membrane prepared by carboxylated chitosan and polyacrylamide for solid-state supercapacitors with wide working temperature range

Supercapacitors are regarded as the forefront of next-generation aqueous energy storage device, while polymeric hydrogel electrolyte is regarded as an ideal electrolyte candidate for flexible aqueous supercapacitor due to its high ionic conductivity and outstanding mechanical properties. However, for lack of renewable property and environmental stability, using hydrogel electrolyte to design supercapacitor will face challenges in front of harsh and sustainable applications. Herein, by using carboxylated chitosan as the matrix material, acrylamide as the monomer, and glycerol as the humectant, a new kind of hydrogel electrolyte membrane could be fabricated, which will meet the standards of renewable and environmental stability. The obtained hydrogel electrolyte membrane exhibits the ionic conductivity of 2.59 × 10−2 S cm−1, tensile strength of 0.8 MPa, and water retention of 55 %. The supercapacitor assembled with hydrogel electrolyte membrane could be operated in a wide temperature range from −11 °C to 70 °C effectively. The supercapacitor also exhibits stable electrochemical performance compared to the devices based on the pristine hydrogel electrolyte membranes. Therefore, this work provides a new insight in exploring hydrogel electrolyte-based device with favorable environmental stability and renewability.