Preparation and performance of activated carbon doped with manganese oxide as an electrode for electrochemical capacitors

Abstract

A MnOx-doped mesoporous activated carbon(AC-MnOx) and an activated carbon(AC) were prepared with and without Mn-containing additives.The microstructure and properties,such as pore volume,pore size distribution,iodine value and methylene blue value,were determined.The electrochemical performance of the two activated carbons as electrodes for electrochemical capacitors were characterized by cyclic voltammetry,AC impedance and charge-discharge at a constant current.Results show that the yield and iodine value of AC-MnOx are lowered by 28.9% and 12.4% respectively compared to AC.The methylene blue value of AC-MnOx is increased by 19.8% compared to AC.Moreover,AC-MnOx has more mesopores than does AC,especially in the range 3.4-4.2 nm.The specific capacitance of an AC-MnOx electrode is 93.8 F/g,which is 140% of that of an AC electrode,indicating that energy density and pseudo-capacitance of the AC-MnOx electrode are higher than those of AC electrode.