Investigation of electrochemical behaviour and annealing effect on zinc cobaltite nanoparticles as working electrode material for energy storage device

Spherical-shaped zinc cobaltite (ZnCo2O4) nanostructures have been formed by a simple sol-gel method using citric acid as a chelating agent. As-prepared samples annealed at different temperature ranges (200-900 degrees C) with various morphologies, crystalline nature, vibrational, as well as different physicochemical properties and surface area are effectively analysed. Amongst them, two zinc cobaltite samples annealed at 600 degrees C (ZCO-6) and 900 degrees C (ZCO-9) were examined for electrochemical behaviours, such as CV, GCD and EIS, using the prepared working electrodes. At high annealed temperature entirely removes organic residue in ZCO and then increases of Zn2+ ions atomic ratios are effective in morphology and crystalline. ZCO-9 exhibits a high specific capacitance of 255.22 F g(-1) at a scan rate of 5 mV s(-1) in CV and the capacitance retention value is 90.56% after 2500 cycles of charge-discharge at the current density of 4 A g(-1). The study results conclude that ZCO-9 electrode can be utilised as a suitable electrode in supercapacitors.