Introduction of Co3O4 into activated honeycomb-like carbon for the fabrication of high performance electrode materials for supercapacitors

Abstract

In this work, a three-dimensional hierarchical carbon framework/Co₃O₄ hybrid composite was fabricated. The three-dimensional hierarchical carbon framework was constructed by thermal vapor deposition on the silica nanosphere templates and etching these templates. The resulting carbon framework was activated using phosphoric acid to control its surface area and porosity. The degree of activation of the carbon framework was optimized by measuring the specific capacitance. The carbon framework electrode activated with 3 M phosphoric acid (HCCA(3)) exhibited the highest specific capacitance (134 F g⁻¹ at 10 mV s⁻¹). Subsequently, Co₃O₄ was formed on the carbon framework via the hydrothermal method. The resulting product HCCA(3)/Co₃O₄ showed a dramatic enhancement in the specific capacitance (456 F g⁻¹ at 1 A g⁻¹) compared with the pristine Co₃O₄ and HCCA(3) electrodes. The proposed HCCA(3)/Co₃O₄ composite can be used for the fabrication of high-performance electrodes.