Structural, optical, morphological, and supercapacitive studies of electrophoretically deposited nanostructured Mn3O4 thin films

Abstract

Herein, the trimanganese tetraoxide (Mn3O4) thin films were deposited by the simple electrophoretic deposition technique using MnSO4 precursor of different molarities (0.05, 0.075, 0.1, and 0.125 M). The effect of different molar concentrations of MnSO4 precursor on structure, morphology, optical properties, and supercapacitive performance has been examined. The deposited thin films were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and Brunauer-Emmett-Teller studies. The Mn3O4 thin films have nanocrystalline tetragonal Hausmannite structure and porous morphology (grass/nanowire and nanoflower) with preferred orientation in the (220) plane. The supercapacitive performance of the Mn3O4 thin film electrodes was evaluated by cyclic voltammetry and galvanostatic charge-discharge techniques. The maximum specific capacitance value 237 F g−1 was obtained for the thin film deposited at 0.05 M MnSO4 concentration and also exhibited 70 % capacitance retention after 2000 cycles. The pseudocapacitive nature of Mn3O4 thin films was confirmed by cyclic voltammetry and electrochemical impedance spectroscopy studies. This study revealed the nanostructured Mn3O4 thin films have the potential to be used as electrode material for supercapacitor applications.