The capacitive properties of amorphous manganese dioxide electrodeposited on different thermally-treated carbon papers

The surface structure of the commercial carbon paper (CP) has been modified through thermal treatment, and then MnO2 was electrodeposited on the thermally-treated carbon paper (TTCP) by cyclic voltammetry (CV) method in the phosphate buffer solution (PBS, pH 9.18) containing KMnO4. The obtained samples were characterized by X-ray diffraction (XRD), X-ray photoelectron energy spectroscopy (XPS) and scanning electron microscopy (SEM). The results showed that the phase of the obtained MnO2 was amorphous, and that the morphology of the MnO2 deposited on the substrates was influenced strongly by the substrates. The capacitive properties of MnO2 deposited on the carbon substrates were investigated by CV, galvanostatic charge/discharge, electrochemical impedance spectroscopy technique. It was found that the specific capacitance of MnO2 deposited on the optimum ITCP can reach to 749 F g(-1) based on the charge/discharge measurement, which was far larger than that on the CP (345 F g(-1)). (C) 2013 Elsevier Ltd. All rights reserved.