Zwitterionic Based Single-Ion Conducting Hydrogel Electrolyte for Flexible Supercapacitor

Abstract

The performance of conventional energy storage with liquid electrolytes have made great progress in the last twenty years, but the inherent instability and leakage issues of liquid electrolytes leads to safety problems. The polymer gel electrolytes (PGEs) offer a perfect solution to these safety concerns and device design due to their flexibility. PGEs are dual ion conductors, in which both cations and anions are mobile and lead to concentration polarization, which leads to poor performance of devices. Hence, the attempt to develop new polymer electrolytes with high single ion transport rates has emerged as a primary strategy for enhancing device performance. But still these systems display ionic conductivities far lower than their polymer/salt mixture counterparts. In order to address these issues, there is need of electrolyte additive which can improve the ionic conductivity of single ion conducting polymer gel electrolyte. Zwitterions, being charged molecules known to enhance the water retention ability, can provide ion migration channel to enhance the charge transportation. Accordingly, in this work we have synthesized single ion conducting hydrogel based polymer gel electrolyte, which has anion covalently bound to the polymer backbone. Furthermore, the synergistic effect of zwitterion as an electrolyte additive has been evaluated by fundamental electrochemical measurement of supercapacitor such as CV, GCD, and EIS measurements.