Ruthenium oxide-carbon composite electrodes for electrochemical capacitors

For amorphous ruthenium, the current-voltage characteristics of cyclic voltammetric (CV) curves depended strongly on the voltage scan rate. At high voltage scan rates, asymmetrical reduction and oxidation current behavior was obtained. The specific capacitance decreased with increasing voltage scan rate. The composite electrode was made by mixing ruthenium oxide powders and activated carbon black. The CV curve symmetry improved significantly at high voltage scan rates using composite electrodes, and the specific capacitance was less sensitive to the voltage scan rate. An electrochemical capacitor made with ruthenium oxide-carbon composite electrodes demonstrated current densities as high as 1.57 A/cm².