Spray pyrolysed vanadium oxide thin films using different ingredients for redox supercapacitor

Vanadium oxide thin films have been prepared on stainless steel substrate by spray pyrolysis using aqueous solutions of ammonium metavanidate, sodium metavanidate, and vanadyl sulphate as ingredients deposited at 673 K. Deposited samples show orthorhombic crystal structure with V2O5 phase having homogeneous, granular and dense surface morphology. Samples show direct band-gap transitions in the energy range 2.30–3.27 eV. The electrochemical capacitive behavior of V2O5 electrodes are investigated by using cyclic voltammetry, electric parameters using chronopotentiometry and internal resistance by electrochemical impedance spectroscopy. Electrochemical performance of the sample electrodes show highest specific capacitance 307.37 F/gm at 5 mV/s, specific energy 18.73 Wh/kg, specific power 36 kW/kg and columbic efficiency (η) 87.50 % in 1 M aqueous KCl. The observed internal resistance is ~1.34 Ω. Electrode exhibits excellent long cycle stability.