Cathodic Electrodeposition of Manganese Oxides for Electrochemical Supercapacitors

Manganese oxide films for electrochemical supercapacitors (ES) have been prepared by cathodic electrolytic and electrophoretic deposition. The cathodic reduction of KMnO4 solutions resulted in the formation of manganese oxide deposits. In another approach electrophoretic deposition (EPD) has been utilized for the deposition of manganese oxide nanoparticles prepared by a chemical precipitation method. The films exhibited pseudocapacitive behavior in a potential window of 0-1 V versus SCE in aqueous 0.5 M Na2SO4 and 0.5 M K2SO4 solutions. The deposition methods allowed the formation of porous films which exhibited a specific capacitance (SC) in the range of up to 240 F/g. The SC decreased with increasing scan rate. The films prepared by electrolytic deposition showed higher SC compared to the SC of EPD deposits.