Metal oxide thin film based supercapacitors

Supercapacitors have been known for over fifty years and are considered as one of the potential energy storage systems. Research into supercapacitors is presently based primarily on their mode of energy storage, namely: (i) the redox electrochemical capacitors and (ii) the electrochemical double layer capacitor. The commonly investigated classes of materials are transition metal oxides (notably, ruthenium oxide) and conducting polymers. Recently, many chemically deposited metal oxide thin film electrodes including ruthenium oxide, iridium oxide, manganese oxide, cobalt oxide, nickel oxide, tin oxide, iron oxide, pervoskites, ferrites etc. have been tested in supercapacitors This review presents supercapacitor performance data of metal oxide thin film electrodes. The supercapacitors exhibited the specific capacitance (Sc) values between 50 and 1100 F g−1, which are quite comparable with bulk electrode values; therefore, it is likely that metal oxide films will continue to play a major role in supercapacitor technology.