Voltammetric Behavior of Ruthenium Oxide in Organic Electrolyte Containing Imidazolium Salt

The pseudo-capacitance of ruthenium oxide electrode has been compared in organic solvent electrolytes having different solutes, tetrafluoroborate salts with tetraethylammonium and ethylmethylimidazolium cations, and various solvents using cyclic voltammetry. Some kinds of solvents such as acetonitrile promote substantial capacitance of ruthenium oxide in imidazolium-based electrolyte salt over tetraethylammonium-based one, while propylene carbonate exhibited no such difference between these two electrolyte systems. The pseudo-capacitance of ruthenium oxide in imidazolium-based electrolyte is stable over cycles under limited anodic potential range of 0.5 V vs. Ag. The contamination of ca. 1000 ppm of water induces further substantial capacitance only for imidazolium-based electrolyte.