Mn-doped activated carbon aerogel as electrode material for pseudo-capacitive supercapacitor: Effect of activation agent

Carbon aerogel (CA) was prepared by a sol-gel polymerization of resorcinol and formaldehyde, and a series of activated carbon aerogels (ACA-X, X = H3PO4, K2CO3, KOH, and ZnCl2) were then prepared by a chemical activation using different activation agent (X represented an activation agent). Specific capacitances of activated carbon aerogels were measured by cyclic voltammetry and galvanostatic charge/discharge methods in 6 M KOH electrolyte. Among the samples prepared, ACA-K2CO3 showed the highest specific capacitance (152 F/g). In order to combine excellent electrochemical performance of activated carbon aerogel with pseudo-capacitive property of manganese oxide, 7 wt% manganese oxide was doped on activated carbon aerogels (Mn/ACA-X) by an incipient wetness impregnation method. Capacitance measurements revealed that Mn/ACA-K2CO3 showed the highest specific capacitance (189 F/g). The enhanced capacitance of Mn/ACA-K2CO3 was attributed to the fine pore structure and outstanding electric properties of activated carbon aerogel as well as the faradaic redox reactions of manganese oxide.

► Activated carbon aerogels (ACA-X, X = H3PO4, K2CO3, KOH, ZnCl2) were prepared.
► Manganese oxide supported on ACA-X (Mn/ACA-X) was prepared.
► Among ACA-X, ACA-K2CO3 showed the highest specific capacitance.
► Among Mn/ACA-X, Mn/ACA-K2CO3 showed the highest specific capacitance.