A Self-Healing Gel Polymer Electrolyte, Based on a Macromolecule Cross-Linked Chitosan for Flexible Supercapacitors

Gel polymer electrolytes with a satisfied ionic conductivity have attracted interest in flexible energy storage technologies, such as supercapacitors and rechargeable batteries. However, the poor mechanical strength inhibits its widespread application. One of the most significant ways to avoid the drawbacks of the gel polymer electrolytes without compromising their ion transportation capabilities is to create a self-healing structure with the cross-linking segment. Herein, a new kind of macromolecule chemical cross-linked network ionic gel polymer electrolyte (MCIGPE) with superior electrochemical characteristics, a high flexibility, and an excellent self-healing ability were designed, based on chitosan and dibenzaldehyde-terminated poly (ethylene glycol) (PEGDA) via dynamic imine bonds. The ionic conductivity of the MCIGPE-65 can achieve 2.75 × 10^-2 S cm^-1. A symmetric all-solid-state supercapacitor employing carbon cloth as current collectors, activated a carbon film as electrodes, and MCIGPE-65 as a gel polymer electrolyte exhibits a high specific capacitance of 51.1 F g^-1 at 1 A g^-1, and the energy density of 7.1 Wh kg^-1 at a power density of 500.2 W kg^-1. This research proves the enormous potential of incorporating, environmentally and economically, chitosan into gel polymer electrolytes for supercapacitors.