Effect of precursor on the morphology and supercapacitor performance of CuCo 2 O 4

Abstract

Two CuCo 2 O 4 spinel crystals with different morphologies were successfully synthesized by one step hydrothermal method and used as active electrode materials for supercapacitors. A chrysanthemum-like CuCo 2 O 4 crystal (CuCo 2 O 4 -C) was obtained by using cobalt chloride and copper chloride as the raw materials, and a rose-like CuCo 2 O 4 crystal (CuCo 2 O 4 -N) was prepared by using cobalt nitrate and copper nitrate. The structural analysis results indicated that CuCo 2 O 4 -C has a more open-framework structure. The following electrochemical tests showed that the CuCo 2 O 4 -C electrode exhibited a better supercapacitive performance than that of CuCo 2 O 4 -N in 6 mol L -1 KOH solution. The specific capacitance of CuCo 2 O 4 -C was 335.8 F g -1 at a current density of 0.5 A g -1 , however, the capacitance of CuCo 2 O 4 -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 CuCo 2 O 4 -C electrode remained at 85% after 2000 cycles, whereas the retention of the CuCo 2 O 4 -N electrode was only 67%. The peculiar structure of chrysanthemum-like CuCo 2 O 4 -C, which affords a highly porous structure and an enhanced specific surface area, helps to explain these results.