Composite of manganese dioxide and electrochemically reduced graphene oxide (MnO2/ERGO) was prepared and investigated as active material in supercapacitor. In order to synthesize the nanocomposite, a thin film of graphene oxide (GO) was formed by electrophoretic deposition (EPD) technique from an aqueous dispersion of GO on stainless steel (SS). GO/SS was electrochemically reduced to form ERGO. Two-step potential method was used to deposit MnO2 on ERGO/SS. MnO2 nanoparticles with dimensions in the range of 40e70 nm were formed as a uniform coating on ERGO/SS. Specific capacitance of MnO2/ ERGO/SS is 392 F g1 at current density of 1 A g1 in 0.5 M Na2SO4, which was higher than 159 F g1 for ERGO/SS. Also, MnO2/ERGO/SS shows higher power and energy densities than ERGO/SS. Due to unique structure of prepared MnO2/ERGO nanocomposite, the capacitive behavior of ERGO is improved.
