Effect of Precursor on the Morphology and Supercapacitor Performance of CuCo2O4

Two CuCo2O4 spinel crystals with different morphologies were successfully synthesized by one step hydrothermal method and used as active electrode materials for supercapacitors. A chrysanthemum-like CuCo2O4 crystal (CuCo2O4-C) was obtained by using cobalt chloride and copper chloride as the raw materials, and a rose-like CuCo2O4 crystal (CuCo2O4-N) was prepared by using cobalt nitrate and copper nitrate. The structural analysis results indicated that CuCo2O4-C has a more open-framework structure. The following electrochemical tests showed that the CuCo2O4-C electrode exhibited a better supercapacitive performance than that of CuCo2O4-N in 6 mol L-1 KOH solution. The specific capacitance of CuCo2O4-C was 335.8 F g(-1) at a current density of 0.5 A g(-1), however, the capacitance of CuCo2O4-N was only 235.3 F g(-1) under the same conditions. Furthermore, at a current density of 3 A g(-1), the capacitance retention of the CuCo2O4-C electrode remained at 85% after 2000 cycles, whereas the retention of the CuCo2O4-N electrode was only 67%. The peculiar structure of chrysanthemum-like CuCo2O4-C, which affords a highly porous structure and an enhanced specific surface area, helps to explain these results.