Electrodeposition of porous manganese oxide with various surfactants for supercapacitor electrodes

초록

Among the various transition metal oxides, manganese oxide is one of the most prospective active materials for pseudo-capacitor owing to their low cost, high abundance, large theoretical specific capacitance and environmentally-friendly properties. [1-3] Furthermore, porous metal oxides have a large specific surface area and pore volume which provide easy contact with the electrolyte, leading to improved electrochemical performance. In this work, porous MnO2 was successfully fabricated by electrodeposition method with various surfactants such as F127, CTAB and SDS onto indium-tin-oxide-coated (ITO) glasses in a standard three-electrode system using a Pt mesh and Ag/AgCl/KCl (sat’d) electrode as the counter electrode and the reference electrode, respectively. The electrodeposition was carried out under constant potential of 1.0 V versus Ag/AgCl/KCl (sat’d) at room temperature, controlling a totally passed charge from 200 mC to 500 mC. The electrolyte consists of proper amount of manganese precursor and surfactant. Crystallinities of the synthesized manganese oxides were investigated by X-ray diffraction (XRD), and the surface composition was measured by X-ray photoelectron spectroscopy (XPS). The morphology and the surface properties of the samples were also obtained by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical properties were determined by cyclic voltammetry (CV) in a standard three electrode system using a potentiostat.