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

The gamma-MnO2/multi-walled carbon nanotube (gamma-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 gamma-MnO2/MWNT composite have been investigated by cyclic voltammetry (CV). A specific capacitance (based on gamma-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 gamma-MnO2/MWNT composite electrode shows excellent long-term cycle stability (only 2.4% decrease of the specific capacitance is observed after 500 CV cycles). (C) 2007 Elsevier Ltd. All rights reserved.