Substrate dependent morphological and electrochemical properties of V₂O₅ thin films prepared by spray pyrolysis

A scheme of substrate dependent self-organization of vanadium oxide has been used to create unique supercapacitor electrodes. In present work, thin films of V₂O₅ were prepared on different substrates by using well known spray pyrolysis technique.The sample depositions were carried out at 673 K, by spraying 0.05 M, 40 ml solution of ammonium metavanadate at the spray rate 10 ml/min. V₂O₅ thin films grown on aluminum (Al), copper (Cu) and stainless steel (SS) substrates shows porous valley and mountains, rough and dense morphology with overgrown agglomeration of nano grains. In electrochemical characterizations, by using standard electrode configurations, specific capacitance values were evaluated from cyclic voltammetry in 1 M KCl, these are 18.43, 1500.0, 439.60 and 250.58 F/g at 5 mV/s for the electrodes deposited on Al, Cu, SS substrates and two electrode cell respectively. Charge discharge behavior of the SS electrode and two electrode cell was observed using chronopotentiometry. This exhibits specific energy, specific power, and coulombic efficiency (η) 84.91 Wh/kg, 120.00 kW/kg and 89.51 % for SS electrode and 19.92 Wh/kg, 65.00 kW/kg and 99.90 % for two electrode cell respectively. Impedance study was carried out in the frequency range 1 mHz–1 MHz depicts less internal resistance of SS electrode ~2.69 Ω and two electrode cell ~3.04 Ω.