Synthesis and characterization of pulsed polymerized poly(3,4-ethylenedioxythiophene) electrodes for high-performance electrochemical capacitors

Poly(3,4-ethylenedioxythiophene) (PEDOT) is electrochemically prepared as a film on flexible thin graphite substrate by short galvanic pulse method in organic media. For comparative studies, PEDOT films are also prepared by potentiostatic polymerization method. The nucleation and growth mechanism for PEDOT film polymerized by short current pulses is presented with morphological and structural studies. The growth of PEDOT is continuous during the pulse off period as confirmed by the deposited mass of PEDOT by these two different methods. The SEM studies of pulse polymerized PEDOT films with different pulse on time show the features of highly porous and ridge like structures which help in rapid migration of dopant ClO4− ions during the charge and discharge processes. The X-ray photoelectron spectroscopy (XPS) studies confirm that in the pulse polymerized PEDOT films polymer chains are fully conjugated with the dopant ClO4− ions. The electrochemical characterization of PEDOT films show that pulse polymerized PEDOT films exhibited high specific capacitance (126.5 F g−1) with an improved energy density and rate kinetics as comparison to the potentiostatically deposited PEDOT films (100 F g−1) in aqueous electrolyte.