Physicochemical and Electrochemical Characterization of Polycyclopenta[2,1-b;3,4-b‘]dithiophen-4-one as an Active Electrode for Electrochemical Supercapacitors

Abstract

Poly(cyclopenta[2,1-b;3,4-b‘]dithiophen-4-one) (PCDT) has been characterized by several electrochemical and spectroscopic techniques so that it can be used as an active electrode material in electrochemical supercapacitors. This polythiophene derivative was prepared by the electrochemical polymerization of cyclopenta[2,1-b;3,4-b‘]dithiophene-4-one (CDT) from a nonaqueous solution (acetonitrile) containing tetraethylammonium tetrafluoroborate. The range of electroactivity of PCDT in nonaqueous media spans at least 2 V. The doping levels measured by cyclic voltammetry and EDAX were found to be 0.19 and 0.14, respectively, for the oxidized-PCDT. Low-frequency capacitance measurements were made by electrochemical impedance spectroscopy to evaluate the film's ability to store charge. Low-frequency capacitances of about ∼70 F/g were found for both the p- and n-doped states. Ionic and electronic resistances were established using both a Randles equivalent circuit and the linear transmission line model to analyze...