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

Composites of mesoporous carbon (CMK-3) and Co3O4 nanosheets grown on nickel foam were successfully synthesized by a simple route. A bare Co3O4 film was synthesized for comparison. With the addition of CMK-3, the Co3O4 nanoparticles self-organize and agglomerate into nanosheets, showing a significant influence by CMK-3 on the morphology. The CMK-3/Co3O4 exhibits an optimal specific capacitance of 1131.3Fg−1 in 3molL−1 KOH aqueous electrolyte at 0.5Ag−1, and a retention ratio of 91% over 3000 cycles, both being much higher than that achieved from the bare Co3O4 film (727Fg−1 of specific capacitance, and 82% capacitance retention ratio), indicating that the CMK-3/Co3O4 nanosheets are very promising as electrode materials for supercapacitor applications.