Zwitterionic silica sulfobetaine grafted activated carbon as electrode material for supercapacitors

This study introduces novel approach to enhance the energy and power capabilities of activated carbon (AC) electrodes through the incorporation of zwitterionic silica sulfobetaine (ZSS). ZSS helps to disperse the aggregation of AC increasing the surface area, thereby increasing specific capacitance, while its zwitterionic nature facilitates ionic transport, improving charge-discharge efficiency. The enhanced electrochemical properties of ZSS-AC were confirmed with cyclic voltammetry with nearly 100 % initial capacitance retention after 5000 cycles, galvanostatic charge-discharge, and impedance spectroscopy with ZSS-AC exhibiting higher specific capacitance of 325 F g(-1) compared to AC with 212 F g(-1). The AC had an energy density of 29.4 W h kg(-1) and a power density of 1339.7 W kg(-1) whilst the ZSS-AC had an energy density of 45.1 W h kg(-1) and a power density of 1218.0 W kg(-1) at 1 A g(-1). These results show grafting ZSS onto AC is a viable solution for enhancing supercapacitor electrode materials.