MnO2/graphene/nickel foam composite as high performance supercapacitor electrode via a facile electrochemical deposition strategy

A novel MnO 2 /graphene (G)/nickel foam (NF) composite as supercapacitor electrode was fabricated by a facile electrochemical deposition approach for the first time. The approach includes electrophoretic deposition of G on NF (EPD-G/NF) and electrodeposition of MnO 2 on EPD-G/NF (MnO 2 /EPD-G/NF). Compared with other methods for preparing MnO 2 /G composite, our green strategy avoids using harsh chemicals (e.g. hydrazine) or high temperature treatment for reducing graphene oxide. Owing to unique structure, specific capacitance ( C s ) of the MnO 2 /EPD-G/NF electrode is as high as 476 F g − 1 at high current density of 1 A g − 1 in 0.5 M Na 2 SO 4 solution, which is the highest C s for MnO 2 /G composites to date, and the C s is higher than that of MnO 2 /NF electrode. Furthermore, it also exhibits high rate capacity, such as 216 F g − 1 of C s at 10 A g − 1 . On the other hand, our strategy provides a versatile method for fabrication of other G-based composites with metal oxide/hydroxide or conducting polymer as supercapacitor electrode.