Sphere-shaped CuCo2O4 nanostructures battery type electrode for supercapacitor via hydrothermal synthesis approach

Abstract

Transition metal oxide (TMO) is expected to be a highly competitive electrode material for energy storage applications based on its superior electrical and theoretical capacity in supercapacitors. However, a larger surface area and higher porosity are required to improve the electrode's electrochemical performance for practical applications. The nanostructured CuCo2O4 nanoparticles was prepared via a simple hydrothermal process with increased surface area and favorable active site to promote electrolyte penetration. The optimal hydrothermal reaction time was investigated to allow nanoparticle overgrowth, which will be critical in determining the specific surface area of the electrode material. The CuCo2O4 prepared at 7 h hydrothermal reaction period, (i.e. CCO-7 h) battery type electrode revealed a capacity of 193 F/g (96.5 C/g) at 3 mA/cm2 and capacity retention of 85.9% over 6000 cycles at 15 mA/cm2. Furthermore, the activated carbon and CCO-7 h (CCO//AC) asymmetric supercapacitor (ASC) exhibited energy and power densities of 2.120 Wh/kg and 277 W/kg, respectively with a capacity retention of 64% after 2000 cycles. The binary metal oxide CuCo2O4 with unique morphology could be a promising battery type electrode for supercapacitor device application.