Use of polymers and their composites with ruthenium oxide as active electrode materials in electrochemical supercapacitors

The composite electrodes consisting of ruthenium oxide and polyaniline as active electrode materials, as well as poly(vinylidene fluoride) and Nafion ® (ethanesulfonyl fluoride, 2-[1-[difluoro-[(trifluoroethenyl) oxy] methyl]-1,2,2,2-tetrafluoroethoxy]-1,1,2,2,-tetrafluoro- tetrafluoroethylene) as binders were synthesized and investigated as electrode materials for applications in electrochemical supercapacitors. The composite electrodes were synthesized by casting a suspension of different amounts of ruthenium oxide in the solutions of the corresponding binders onto the glassy carbon electrodes. Various quantities of polyaniline were deposited onto the composite electrodes by the cyclic voltammetry method using different number of potential cycles. The electrochemical properties of the composite electrodes were investigated by cyclic voltammetry and electrochemical impedance spectroscopy techniques. The specific capacitances obtained were compared and the charging/discharging mechanism was elucidated. The results show that the overall properties of the composite electrodes strongly depend on the quantities of different components in the mixture and the type of the binder. The best electrochem ical properties were achieved when poly(vinylidene fluoride) was used as a binder. In this case utilization of RuO2 was maximized and specific capacitance higher than 500 F/g was achieved. After the deposition of PANI on this composite, specific capacitance was increased to 700 F/g.The difference in the behaviour between two binders is explained by the difference in their physical and chemical properties and the different role they assume in the resulting composite materials.