Preparation and characterization of aligned carbon nanotube-ruthenium oxide nanocomposites for supercapacitors

A novel type of ruthenium oxide (RuO2)-modified multi-walled carbon nanotube (MWNT) nanocomposite electrode (RuO2/MWNT) for super-capacitors has been prepared. The nanocomposites were formed by depositing Ru by magnetic-sputtering in an Ar/O-2 atmosphere onto MWNTs, which were synthesized on Ta plates by chemical vapor deposition. Cyclic voltammetry, chronopotentiometry, and electrochemical impedance measurements were applied to investigate the performance of the RuO2/MWNT nanocomposite electrodes. The capacitance of the M WNT electrodes in 1.0 m H2SO4 is significantly increased from 0.35 to 16.94 mF cm(-2) by modification with RuO2. The RuO2 film on the surface of the nanotubes is composed of small crystal grains with tilted bundle-like microstructures, as observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results demonstrate a promising route to prepare RuO2/MWNT-based double-layer supercapacitors.