Carbon Fabric Supported Manganese and Ruthenium Oxide Thin Films for Supercapacitors

Ru oxide/carbon fabric (CF), Mn oxide/CF, and binary Mn-Ru oxide/CF composites were prepared by reactions between the reductive functional groups on the CF and Ru (VI), Ru(VII) + Mn(VII), and Ru(VII) + Mn(VII) mixtures, which resulted in spontaneous deposition of the metal oxides as thin films on the carbon fiber surfaces. Capacitances, resistances, stabilities, and power versus energy densities were measured in acidic (Ru oxide/CF), neutral (Mn oxide/CF), and basic (all composites) electrolytes. A maximum average specific capacitance of 824 +/- 152 F/g was obtained for the Ru oxide component of a 7.4% Ru oxide/CF composite in 1 M H(2)SO(4). Mn oxide/CF composites exhibited specific capacitances in bases that were greater than 1000 F/g for the Mn oxide component, but not stable to cycling. The mixed Mn-Ru oxide/CF composites were significantly more stable and also exhibited very high specific capacitances for the oxide component. (C) 2011 The Electrochemical Society. [DOI:10.1149/1.3525591] All rights reserved.