Electrochemical behavior of polyaniline: A study by electrochemical impedance spectroscopy (EIS) in low-frequency

Conducting polymers are increasingly attracting the interest of many researchers in different areas due to their good conductivity, stability and easy preparation. Polyaniline is heavily studied in sensors, corrosion protection, electrochromic devices, and supercapacitors, however, even with numerous applications, there are still few pieces of literature that report their electrochemical behavior in regions low-frequency of by electrochemical impedance spectroscopy (EIS). In this work, polyaniline was electropolymerized by galvanic synthesis (chronoamperometry) in stainless steel substrate. Its performance was evaluated by cyclic voltammetry (CV) galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). It was observed in its low-frequency pseudocapacitive analysis, in the benzoquinone and hydroquinone intermediate regions, capacitance values above 100 mF·cm−2, and in the emeraldine state, 295 F·g−1 was obtained. Such results provide a better and detailed understanding of PANI oxidation and reduction processes and could optimize the use of the polymer in various fields of applications.