Sol-gel synthesis of manganese oxide films and their predominant electrochemical properties

• Manganese oxide films prepared by sol-gel method followed by oxidative annealing.
• Its specific capacitance is 360 F g−1 at 0.82 A g−1 in 0.5 M Na2SO4 electrolyte.
• Its energy density is 48.8 Wh Kg−1 at 1161.6 W Kg−1.
• At the current density of 0.82 A g−1 it presents excellent cycling.

In this paper, mesoporous manganese oxide films are easily grown on stainless steel sheet by post chemical bath deposition oxidative annealing by mixing potassium permanganate (KMnO4) with manganese (II) sulphate (MnSO4) in an acidic medium. The prepared films are characterized by X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), proton elastic backscattering spectrometry (EBS) to obtain the phase, morphology and composition respectively. Electrochemical properties of the manganese oxide films are elucidated by cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) in 0.5 M Na2SO4 electrolyte. A specific capacitance (SC) of the amorphous MnO2 film is found to be 360 F g−1 at current density of 0.82 A g−1 and remains it's 92.7% value after 200 cycles. The film exhibits excellent power density, indicating the superiority for supercapacitor electrode.