Synthesis and Electrochemical Characterisation of Zinc Cobalt Bimetallic Oxide as an Advanced Positrode Material for Supercapacitor Application

Abstract

The optimization and development of efficient, cost effective, eco-friendly synthesis method for advance electrode material for application in supercapacitor as energy storage device has become essential. We studied the use of simple facile cost-effective hydrothermal method for the synthesis of bimetallic oxides in this research. We report the successful synthesis of ZnCo2O4 with spinel structure and urchin like morphology suited for application in supercapacitor electrode material. ZnCo2O4 material is characterized by standard techniques, its electrochemical performance is studied in three- electrode system using 6M KOH electrolyte solution. ZnCo2O4 exhibites high specific capacitance of 864.18 Fg-1 at 1 Ag-1 current density which is higher than CoZn2O4 and superior to ZnO and CoO, and also shows faster electron-transfer kinetics, excellent rate capability with 51% retention of specific capacitance in higher current density of 20 Ag-1, shows excellent cyclic stability maintaining 71% of its capacitance after 4,000 cycles. The improved performance results from the synergistic redox activity of Zn and Co, enhanced electron transport, and optimized porous morphology that favours ion diffusion. This paper demonstrates ZnCo2O4 characteristics are better than previously reported data making it as an effective positive electrode material for high-capacity supercapacitors.