Electrochemically induced deposition method to prepare γ-MnO2/multi-walled carbon nanotube composites as electrode material in supercapacitors

The γ-MnO2/multi-walled carbon nanotube (γ-MnO2/MWNT) composite has been prepared by electrochemically induced deposition method. The morphology and crystal structure of the composite were investigated by X-ray diffraction and scanning electron microscopy, respectively. The capacitive properties of the γ-MnO2/MWNT composite have been investigated by cyclic voltammetry (CV). A specific capacitance (based on γ-MnO2) as high as 579 F g−1 is obtained at a scan rate of 10 mV s−1 in 0.1 M Na2SO4 aqueous solution. Additionally, the γ-MnO2/MWNT composite electrode shows excellent long-term cycle stability (only 2.4% decrease of the specific capacitance is observed after 500 CV cycles).