Nanostructures and Capacitive Properties of Manganese Oxide Film Synthesized by Hydrothermal Electrochemical Process

For application in a supercapacitor as electrodes, nano-scaled manganese oxide films were deposited on titanium substrates in manganese acetate solution using the hydrothermal electrochemical process. The effects of synthesis temperature, pH, and the concentration of manganese acetate on the material characteristics and capacitive behavior of manganese oxide film were investigated. The complex tri- and divalent hydrous manganese oxides examined using X-ray photoelectron spectroscopy (XPS) and Raman scattering spectroscopy were obtained at 60 °C in 0.2 M neutral solution. A maximum specific capacitance (SC) of 244 F g^-1 was measured using cyclic voltammetry (CV) at 25 °C in 0.1 M Na₂SO₄ within the range of 0–1 V. The nanometer scale surface morphology of the film was altered by varying the synthesis temperature, pH, and the concentration of the solution. In addition to the surface morphology, the extent of hydration in the manganese oxide film also affected the capacitive properties.