Anodic deposition of hydrous ruthenium oxide for supercapacitors

This communication demonstrates the success in the anodic deposition of hydrous ruthenium oxide (denoted as RuO2·xH2O) from RuCl3·xH2O in aqueous media with/without adding acetate ions (CH3COO−, AcO−) as the complex agent. The benefits of as-deposited RuO2·xH2O include the low electron-hopping resistance and the low contact resistance at the Ti-RuO2·xH2O interface which are clarified in electrochemical impedance spectroscopic (EIS) studies. The cycling stability, specific capacitance, and power performance of as-deposited RuO2·xH2O are further improved by annealing in air at 150 °C for 2 h. The morphologies of as-deposited and annealed RuO2·xH2O films, examined by scanning electron microscopy (SEM), are very similar to that of thermally decomposed RuO2. The high onset frequencies of 660 and 1650 Hz obtained from EIS spectra for the as-deposited and annealed RuO2·xH2O films, respectively, definitely illustrate the high-power merits of both oxide films prepared by means of the anodic deposition without considering the advantages of its simplicity, one-step, reliability, low cost, and versatility for electrode preparation.