Molybdenum Oxide Electrodes for Asymmetric Supercapacitor Application: Effect of MoO ₃ Concentration

The low‐cost, binder‐free chemical bath deposition (CBD) method was utilized to deposit molybdenum oxide (MoO 3 ) thin films on stainless steel (SS) substrates at various concentrations of sodium molybdate (Na 2 MoO 4 ) precursor (0.025–0.1 M) and applied as an anode for supercapacitive charge storage. The effect of precursor concentration on the physicochemical properties of electrodes was studied. The MO 3 thin films (synthesized using a 0.075 M concentration of Na 2 MoO 4 precursor) exhibited mass loading of 0.56 mg cm −2 , a hexagonal crystal structure and microrod‐like surface morphology. The formation of MoO 3 was proved by Raman and (Energy Dispersive X‐ray Analysis) EDAX studies. The MO3 thin film showed a specific capacitance (C s ) of 958.9 F g −1 at 5 mA cm −2 current density. An aqueous asymmetric supercapacitor (ASC) device was assembled using MoO 3 as an anode and polyaniline (PANI) as a cathode. The assembled MoO 3 //H 2 SO 4 //PANI device showed a C s of 53.7 F g −1 with an energy density (ED) of 14.4 Wh kg −1 at a power density (PD) of 1.3 kW kg −1 and 83.7% capacitive retention over 1500 cyclic voltammetry (CV) cycles.