Abstract
The electrochemical (EC) properties and stability of hydrous ruthenium oxide (denoted as RuO x ·nH 2 O) and ruthenium-iridium oxide (denoted as (Ru+Ir)O y ·mH 2 O) were systematically investigated in 0.5M H 2 SO 4 by cyclic voltammetry (CV) and chronopotentiometry (CP). The EC characteristics of RuO x ·nH 2 O and (Ru+Ir)O y ·mH 2 O annealed at temperatures equal to/above 200°C were demonstrated to be more applicable for the EC supercapacitors. The crystalline information of these oxides annealed in air for 2 h up to 300°C was obtained from the X-ray diffraction (XRD) spectra. The morphologies of these oxide-coated electrodes were examined by a scanning electron microscope (SEM). The effect of annealing temperatures on the surface composition of (Ru+Ir)O y ·mH 2 O was studied by X-ray photoelectron spectroscopy (XPS). © 2002 Elsevier Science B.V. All rights reserved.