Rapid synthesis of homogeneous MnO2/multi-wall carbon nanotubes nanostructure and its electrochemical capacitive behavior

A homogeneous composite of MnO2/multi-wall carbon nanotubes (MnO2/MWCNTs) was rapidly and efficiently synthesized by a redox reaction of MnO4- and Mn2+ on the MWCNTs under ultrasonic irradiation. The structure and morphology of the obtained MnO2 and MnO2/MWCNTs composite were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy. Electrochemical investigation indicated that the maximum specific capacitance of the MnO2/MWCNTs composite, measured by galvanostatic charge-discharge test, was 315 F g(-1). compared to the pristine MnO2 (192 F g(-1)) and MWCNTs electrode (25 F g(-1)), showing the synergistic effect of MWCNTs and MnO2. The homogeneous hybrid nanostructure and the good conductivity of MWCNTs were considered to be responsible for its preferable electrochemical performances. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.