Bipotential deposition of nickel-cobalt hexacyanoferrate nanostructure on graphene coated stainless steel for supercapacitors

Graphene oxide (GO) was deposited on inexpensive and mechanically stable stainless steel (SS) electrode by electrophoretic deposition (EPD) technique. GO was reduced electrochemically in NaNO3 to obtain electrochemically reduced graphene oxide (ERGO). Next, Hybrid nickel-cobalt hexacyanofarrate (NiCoHCF) nanoparticles were deposited from solution containing Ni+2 and Co+2 with ratio of 1:1 on ERGO/SS by bipotential method. Morphological investigation of prepared sample by scanning electron microscopy showed the presence of nanoparticles with diameters in the range of 15-50 nm. Crystal structure of nanocomposite was investigated by X-ray diffraction technique. Electrochemical behavior of prepared film indicates that hybrid nanocomposite has higher specific capacitance (411 F g−1) than ERGO (185.2 F g−1) in KNO3 solution at current density of 0.2 A g−1. In other words, pseudocapacitor that is formed based on the faradaic behavior of NiCoHCF can improve the capacitive performance of ERGO.