Optimizations of preparative parameters in potentiodynamic synthesis of cobalt oxide thin films: Capacitive approach

Abstract

The present article reports synthesis of Co₃O₄ thin films by facile potentiodynamic-electrodeposition technique using variations in the preparative parameters such as ingredient, solution concentration and deposition time. The prepared samples were analysed using XRD, FE-SEM, TEM, cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. Crystallographic study shows polycrystalline face centered cubic spinel structure of the deposit. Cyclic voltammogram reveals pseudocapacitive behavior. The calculated highest value of specific capacitance at the scan rate 5 mV/s was 237.68 F/gin 1 M KOH, within the potential window -0.92 to 0.45 V versus Ag/AgCl. The calculated maximum value of specific energy, specific power and columbic efficiency from chronopotentiometry were 4.91 Wh/kg, 28.69 kW/kg and 94.78%, respectively. The internal resistance observed using electrochemical impedance spectroscopy was~ 3.55 Ω.