Improving the utilization of ruthenium oxide within thick carbon-ruthenium oxide composites by annealing and anodizing for electrochemical supercapacitors

The effects of annealing in air and anodizing on the capacitive behavior of carbon-ruthenium (denoted as C-Ru) composites fabricated by wet impregnation were investigated in 0.1 M H2SO4 by cyclic voltammetry (CV) and chronopotentiometry (CP). The utilization of Ru species within the thick composites (approximate to 1000 mum) was greatly promoted by annealing in air at 240 degreesC for 8 h and anodizing in 0.1 M H2SO4 at 1.2 V for 1.5 h, due to the formation of Ru oxide and the transformation into a hydrous nature and the maximal specific capacity of Ru oxide (760 F g(-1) based oil RuO2) could be obtained. The crystalline information of the composites with annealing at different temperatures was obtained from X-ray diffraction (XRD) patterns. The morphology of C-Ru composites was examined by scanning electron microscope (SEM). The specific surface area and pore-size distribution of the composites with annealing and/or anodizing were analyzed by the BET method. (C) 2002 Elsevier Science B.V. All rights reserved.