PERFORMANCE EVALUATION OF POLY 3-(PHENYLTHIOPHENE) DERIVATIVES AS ACTIVE MATERIALS FOR ELECTROCHEMICAL CAPACITOR APPLICATIONS

Electroactive polymers from 3-(4-fluorophenyl)thiophene, 3-(4-cyanophe nyl)thiophene, 3-(4-methylsulfonylphenyl)thiophene, and 3-(3,4-difluor ophenyl)thiophene were electrochemically deposited onto carbon paper e lectrodes from tetramethylammonium trifluoromethanesulfonate (Me4NCF3S O3)/acetonitrile and/or tetraethylammonium tetrafluoroborate (Et-4-NBF 4)/acetonitrile electrolyte solutions. The morphologies and electroche mical performance of the films were shown to depend on both the growth and cycling electrolytes. Constant current multicycle tests were perf ormed on model single-cell devices using the type III capacitor config uration at high voltage (2.8-2.9 V). Active material energy and power densities of up to 50 Wh/kg and 5 kW/kg were achieved at discharge rat es of 50 and 10 mA/cm(2), respectively. The long-term stabilities (up to 1000 cycles) of these polymers were investigated by repeated chargi ng and discharging using cyclic voltammetry in both the p- and n-dopin g regimes.