Characterization of porous cobalt hexacyanoferrate and activated carbon electrodes under dynamic polarization conditions in a sodium-ion pseudocapacitor

Abstract We report here the activated carbon and cobalt hexacyanoferrate composite, which is applied as the electrode materials in symmetric supercapacitors containing a 1.0 M Na2SO4 aqueous electrolyte. This novel material combines high specific surface area and electrochemical stability of activated carbon with the redox properties of cobalt hexacyanoferrate, resulting in maximum specific capacitance of 329 F g−1 with large voltage working window of 2.0 V. Electrochemical studies indicated that cobalt hexacyanoferrate introduces important pseudocapacitive properties accounting for the overall charge-storage process, especially when I