Nanocrystalline metal oxides dispersed multiwalled carbon nanotubes as supercapacitor electrodes

RuO2/MWNT, TiO2/MWNT, and SnO2/MWNT nanocrystalline composites for supercapacitor electrodes have been synthesized by chemical reduction method using functionalized MWNT and respective salts. MWNT have been synthesized by thermal catalytic chemical vapor deposition (CCVD) over hydrogen decrepitated Mischmetal (Mm)-based AB3 alloy hydride catalysts. Structural and morphological characterizations of metal oxide dispersed MWNT have been carried out using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM and HRTEM), energy dispersive X-ray analysis (EDAX), and Raman spectroscopy. Electrochemical performance of these electrodes has been investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. Specific capacitance of RuO2, TiO 2, and SnO2 dispersed MWNT electrodes increases compared to that pure MWNT electrode due to the pseudo capacitance of the nanocrystalline metal oxides dispersed on the functionalized MWNT. The present study shows the potential of cost-effective TiO2/MWNT novel nanocrystalline composite material for electrochemical double layer capacitor. © 2007 American Chemical Society.