Synthesis of polypyrrole film by pulse galvanostatic method and its application as supercapacitor electrode materials

Polypyrrole (PPy) film-coated stainless steel electrodes were prepared from aqueous solution containing 0.5 M p-toluene sulphonic acid and 0.1 M pyrrole using pulse galvanostatic method (PGM) and galvanostatic method (GM). The morphology was characterized by scanning electron microscopy. The electrochemical properties of PPy films were investigated with cyclic voltammetry, charge–discharge tests, and ac impedance spectroscopy. The results showed that the PGM-PPy films exhibited higher specific capacitance, better high-rate discharge ability and lower resistance, and were more promising for applications in supercapacitor than GM-PPy films. The specific capacitance (SC) of PGM-PPy films was 403 F g⁻¹ in 1 M H₂SO₄ electrolyte and 281 F g⁻¹ in 1 M NaNO₃ electrolyte.