Formation of CMK-3/Co3O4 nanosheets on nickel foam with markedly enhanced pseudocapacitive properties

Composites of mesoporous carbon(CMK-3) and Co_3 O_4 nanosheets grown on nickel foam were successfully synthesized by a simple route. A bare Co_3 O_4 film was synthesized for comparison. With the addition of CMK-3, the Co_3 O_4 nanoparticles self-organize and agglomerate into nanosheets, showing a significant influence by CMK-3 on the morphology. The CMK-3/Co_3 O_4 exhibits an optimal specific capacitance of 1131.3 Fg~(-1) in 3 mol L-1 KOH aqueous electrolyte at 0.5 Ag-1, and a retention ratio of 91% over3000 cycles, both being much higher than that achieved from the bare Co_3 O_4 film(727 Fg~(-1) of specific capacitance, and 82% capacitance retention ratio), indicating that the CMK-3/Co_3 O_4 nanosheets are very promising as electrode materials for supercapacitor applications.