Abstract
The electrochemical and textural characteristics of various hydrous ruthenium-iridium oxides (denoted as (Ru+Ir)O x ·nH 2 O) grown by cyclic voltammetry (CV) were systematically studied for the application of electrochemical (EC) capacitors. The faradaic pseudocapacitance of (Ru+Ir)O x ·nH 2 O reached the maximum when the depositing solution contained 5 mM RuCl 3 ·xH 2 O and 1 mM IrCl 3 ·xH 2 O. The linear dependence of C cp on C q* measured respectively by chronopotentiometry (CP) and CV at various (Ru+Ir)O x ·nH 2 O deposits was found to be independent of the compositions of oxides. The intercalation of IrO x ·nH 2 O within the RuO x ·nH 2 O matrix promoted the utilization of electroactive oxyruthenium species while the presence of IrCl 3 ·xH 2 O depressed the rate of (Ru+Ir)O x ·nH 2 O deposition. These effects were further supported by the textural results of these binary hydrous oxides examined by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS).