Abstract
The high specific capacitance of ruthenium oxide (denoted as RuO x ) nanoparticles prepared by a modified sol-gel method with annealing in air for supercapacitors was demonstrated in this work. The specific capacitance of activated carbon (denoted as AC) measured at 5mA/cm 2 is significantly increased from 26.8 to 38.7F/g by the adsorption of RuO x nanoparticles with ultrasonic weltering in 1M NaOH for 30min. This method is a promising tool in improving the performance of carbon-based double-layer capacitors. The total specific capacitance of a composite composed of 90wt.% AC and 10wt.% RuO x measured at 25mV/s is about 62.8F/g, which is increased up to ca. 111.7F/g when RuO x has been previously annealed in air at 200 °C for 2h. The specific capacitance of RuO x nanoparticles was promoted from 470 to 980F/g by annealing in air at 200°C for 2h. The nanostructure of RuO x was examined from the transmission electron microscopic (TEM) morphology. © 2003 Elsevier B.V. All rights reserved.