Electrochemical supercapacitive performance of potentiostatically cathodic electrodeposited nanostructured MnO2 films

Nanostructured MnO2 films were prepared via cathodic electrodeposition under potentiostatic condition. X-ray diffraction (XRD) analyses reveal that the deposited films possess the hexagonal phase of epsilon manganese dioxide (epsilon-MnO2). Fourier transform infrared (FTIR) spectroscopy studies also confirm the manganese dioxide phase of the deposited films. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies show that the film deposited at the potential of 0.2 V has a porous network structure which is made of sparsely distributed grains. Cyclic voltammetry studies show the maximum specific capacitance to be 259.4 F/g at the scan rate of 5 mV/s for the film deposited at the potential of 0.2 V, while the chrono charge-discharge measurements on the film exhibit the maximum specific capacitance to be 325.6 F/g at the current density of 1 mA/cm(2). The variation in specific capacitance values of the films deposited at different potentials is attributed to different morphologies of the films.