Physical and electrochemical characterization of hydrous ruthenium oxide/ordered mesoporous carbon composites as supercapacitor

Abstract

Ruthenium oxide/ordered mesoporous carbon composites materials were prepared by impregnating an ordered mesoporous carbon CMK-3 with RuCl 3 · xH 2O solution followed by annealing in nitrogen atmosphere from 80 to 400 °C. The content of ruthenium oxide in the composites ranged from 10.0 to 30.7 wt.%. X-ray diffraction (XRD), thermogravimetric analysis (TGA), nitrogen adsorption measurement and transmission electron microscopy (TEM) were used to characterize the composites. The results showed that the ruthenium oxide deposited on CMK-3 mesoporous carbon was hydrous and amorphous when annealed up to 400 °C. The specific capacitance of the composites was determined by cyclic voltammetry. Such composites had high specific capacitance, which was derived from the high specific surface area of CMK-3 mesoporous carbon and the pseudo-capacitance of amorphous RuO 2. In addition, the specific capacitance depended on the annealing temperature and the RuO 2 content. As the temperature increased, the specific capacitance decreased. In contrast, the specific capacitance increased with higher RuO 2 content and reached 633 F/g with a heavy content. However, as the RuO 2 content increased, its contribution to the pseudo-capacitance became poorer. The rate capability of the composite electrodes also decreased as a function of RuO 2 content, due to an increase in the equivalent series resistance (ESR) and the overall capacitance.