Redox deposition of birnessite-type manganese oxide on silicon carbide microspheres for use as supercapacitor electrodes

Silicon carbide microsphere/birnessite-type MnO_x (SiC/B-MnO _x) composites were prepared by removal of a SiO₂ layer with redox deposition of birnessite-type MnO_x for supercapacitor electrode materials. The characterization studies showed that the birnessite-type MnO_x in the composite was homogeneously deposited on the SiC surface. The capacitive properties of the as-prepared SiC/B-MnO _x electrodes were measured in a three-electrode system using 1 M Na₂SO₄(aq) as the electrolyte. The SiC/B-MnO _x(6) electrode, fabricated using a MnO_x/SiC feeding ratio of 6:1, displayed a specific capacitance of 251.3 F g^-1 at 10 mV s^-1. Such excellent electrochemical performance is attributed to an increase in the electrical conductivity in the presence of silicon carbide, an increase in the effective interfacial area between MnO_x and the electrolyte, and the contact area between MnO_x and silicon carbide. The deposition of birnessite-type MnO_x on a SiC surface may be a prospective fabrication technique for electrode materials for supercapacitors.