Iron-Cobalt Oxides Nanoparticles Loaded Crumpled Graphene for Supercapacitor (Invited)

Mixed transition metal oxides (MTMOs) have been explored as attractive electrode materials for supercapacitors owing to their higher electronic conductivity and larger specific capacitance compared with simple transition metal oxides. Among MTMOs, cobalt-based binary metal oxides such as Iron (Fe)-Cobalt (Co) oxides have emerged as alternative electrode materials for supercapacitors because they have the advantages of low cost, natural abundance, and environmental friendliness. Recently, graphene-based Fe-Co oxide composites have become of particular interest for their improved electrochemical performance of supercapacitors due to the synergetic effect of both materials. In this study, we present three-dimensional (3D) crumpled graphene (CGR) decorated with Fe-Co oxide nanoparticles to determine which molar ratio of Fe/Co can exhibit higher electrochemical supercapacitor performance. The CGR/iron-cobalt oxide composites were synthesized in different molar ratios of Fe/Co from iron (III) nitrate hexahydrate and cobalt (II) nitrate hexahydrate, respectively, via aerosol spray pyrolysis. Sizes of Fe-Co oxides nanoparticles ranged from 5 to 10 nm when loaded onto 500 nm CGR. The electrochemical properties of the CGR/Fe-Co oxide composites with different molar ratios of Co/Fe were examined to compare the electrochemical performance. The CGR/Fe-Co oxide electrodes fabricated at the Fe/Co ratio of 0.1 showed the highest performances in the capacitance and electrical conductivity among those electrodes with different molar ratios of Co/Fe.