Facile synthesis of ZnCo2O4 micro-flowers and micro-sheets on Ni foam for pseudocapacitor electrodes

Abstract Two structures composed of ZnCo 2 O 4 micro-flowers and ZnCo 2 O 4 micro-sheets on Ni foam were synthesized through a facile hydrothermal method and annealing treatment. These two different structures were evaluated as electrodes for supercapacitors. The ZnCo 2 O 4 micro-flowers electrodes offer specific capacitance of 2256 F/g at 2 mA/cm 2 , excellent rate capability of 84% as the current density increasing from 2 to 20 mA/cm 2 . The ZnCo 2 O 4 micro-sheets electrodes could achieve a specific capacitance of 2037 F/g at 2 mA/cm 2 and low rate capability of 46% as the current density increasing from 2 to 20 mA/cm 2 . The reasons of these different electrochemical performances of ZnCo 2 O 4 micro-flowers and ZnCo 2 O 4 micro-sheets are discussed. This study provides a comprehension of structure dependent of the electrochemical performance of electrodes.