Anion Doping-undoping Process of Electrochemically Polymerized

The electrochemical anion doping-undoping of the film, (C₄H₃N)_x, prepared by the electrochemical polymerization of pyrrole was investigated under potentiostatic conditions. The impedance behavior of the doping-undoping process into the C₄H₃N)_x film was measured by the FFT method and it was represented by the Randles-type equivalent circuit. The resistive R_r value sensitively reflected the variation of doping-undoping process of the C₄H₃N)_x film in a similar, manner as in the case of a polyacetylene film, suggesting that the dopant diffusion process into the polypyrrole film controled the doping process. A charging-discharging of simple Li-C₄H₃N)_x battery in propylene carbonate was also investigated. The resistive Rr value of the cell clearly had the correlation with open-circuit voltage and the charged conditions.