Optimization of Anion Exchange Membranes Derived from Cross-Linked Chitosan-Poly (diallyldimethylammonium chloride) for All-Solid Electrochemical Capacitors

Abstract

In this study, an advanced anion exchange membrane with high hydroxide ion (OH-) conductivity is fabricated, which consists of cross-linked chitosan and poly (diallyldimethylammonium chloride) (CS/PDDA) composites. The effects of annealing temperature, cross-linker concentration and cross-linking time on OH- conductivity are evaluated using AC impedance technique, along with water uptake and swelling properties of membranes. It is found that by cross-linking modifications, the as-prepared CS/PDDA membrane exhibits a high OH- conductivity of 0.024 S cm-1 under ambient conditions, at a polymer composition of CS/PDDA = 1:0.5 by mass. When served as separator and electrolyte, such a membrane exhibits a high specific capacitance of 3.76 mF cm-2 at 1 V s-1, when it was sandwiched between two symmetrical self-made CNT electrodes. In particular, an excellent rate capability reaching up to 10 V s-1 is realized, indicating its promising potential for application in an all-solid electrochemical capacitor.