Study on electrochemical performance of conductive Polypyrrole
                                                          ZHANG Teng teng, WANG Xiang jiang
                   （School of Mechanical Engineering, University of South China, Hengyang 421001, China）

Abstract: Aiming at the electrochemical performance of polypyrrole （PPy）, the preparation process, redox reaction, AC impedance and step response of PPy were studied. The polypyrrole （PPy） film was prepared on the surface of polydual vinylidene fluoride （PVDF） film by electrodeposition in the electrochemical workstation. The redox reaction was analyzed by cyclic voltammetry （CV curve）, the internal ion migration process was explored, the expansion and contraction of PPy was analyzed, and the capacity under different sweep was calculated.The impedance of the PPy was tested by AC impedance spectroscopy （EIS）, the equivalent circuit model was established by ZSimpwin software and the conductivity was calculated according to the fitted data. Then, the charge time constant of PPy was investigated. The results indicate that the cyclic voltammetry can effectively describe the redox state and the migration of the internal ions of the PPy film. The AC impedance test can be equivalent to the R（C（RW）） circuit of the PPy, the constant potential step curve can accurately describe the PPy film charge and discharge time constant.

Key words: Polypyrrole; cyclic voltammetry; AC impedance; constant potential step; constant current charge and discharge