Supercapacitor Performance of Hydrous Ruthenium Oxide Electrodes Prepared by Electrophoretic Deposition

Electrodes of hydrous ruthenium oxide were prepared by electrophoretic deposition (EPD) without binder and carbon additives. Through EPD and heat-treatment , a network of nanoparticles (ca. ) was developed with porous structure (packing density ca. ). As a result, high specific capacitance ( at and at ) was obtained, where specific energy and power were as high as (at ) and (at ), with loading weight of . At higher loading weight , specific capacitance decreased gradually. Also, volumetric energy was high because low-density additives, such as porous carbon and binder, were not used. From electrochemical impedance spectroscopy, specific energy and power were calculated, showing good agreement with values measured by CV. The decrease of rate capability with thicker electrode could be correlated by distribution of the time constant , which was calculated from impedance spectra by using an equivalent circuit with multiple Warburg elements.