Conducting polymer with metal oxide for electrochemical capacitor - Poly(3,4-ethylenedioxythiophene) RuOx electrode

Electrodes made by depositing ruthenium oxide on conducting poly(3,4-ethyle nedioxythiophene) (PEDT) were studied for their electrochemical and impedan ce properties. In acidic electrolytes the PEDT-RuOx composite electrodes ex hibited large capacitance due to contributions from the double-layer capaci tance and the faradaic capacitance. Optimization of the thickness of the co nducting polymer film and the amount of ruthenium deposition was found nece ssary to realize large specific capacitance. The specific capacitance based on the combined mass of PEDT-RuOx was 420 F/g, and the specific capacitanc e based on the mass of RuO2 was 930 F/g. The energy storage density of a ca pacitance cell constructed with a pair of PEDT-RuOx electrodes reached 27.5 Wh/kg when the cell was charged to 1.0 V. The impedance analysis of the co mposite electrode revealed that both the double-layer capacitance and the p seudocapacitance originating from both PEDT and RuOx contribute to large sp ecific capacitance. (C) 2001 The Electrochemical Society. All rights reserv ed.