Electrochemical performance amelioration at higher scan rates of electrodeposited cobalt oxide electrode by Ru incorporation

In the present work, ruthenium incorporated cobalt oxide thin films were synthesized on stainless steel substrates using potentiodynamic electrodeposition via aqueous route. The aim of the Ru incorporation is to ameliorate the electrochemical performance of the pristine cobalt oxide thin film. XRD, FESEM and TEM were used for the structural and morphological characterizations while cyclic voltammetry (CV) and chronopotentiometry were used for the electrochemical characterizations of the prepared samples. The XRD patterns of the deposited samples shows polycrystalline face centered cubic and tetragonal type crystal structures for Co₃O₄ and RuO₂ respectively. TEM study confirms compact granular type morphology with crystalline nature as depicted from SAED analysis. Prepared samples show nearly hydrophobic nature. CV study reveals hybrid capacitive behavior with optimum specific capacitance 296.55 F/g at the scan rate 2 mV/s in 1 M KOH. Ru incorporation showed improvement in the electrochemical stability achieving 94.10% retention after 1000 cycle at the scan rate 100 mV/s in 1 M KOH. Electrochemical impedance spectroscopy (EIS) reveals the 0.88 Ω internal resistance of optimized electrode.