Electrochemical polymerization of polyaniline doped with Cu2+ as the electrode material for electrochemical supercapacitors

Abstract

Polyaniline doped with Cu²⁺ (PANI/Cu²⁺) was synthesized by cyclic voltammetry on the stainless steel mesh with various concentrations of copper sulfate (CuSO₄·5H₂O) in an electrolyte. The structure and morphology of PANI and PANI/Cu²⁺ films were characterized by Fourier transform infrared, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The electrochemical properties of PANI and PANI/Cu²⁺ films were investigated by cyclic voltammetry, galvanostatic charge–discharge testing and electrochemical impedance spectroscopy (EIS) in a 0.5 mol L⁻¹ H₂SO₄ electrolyte in a three-electrode system. The specific capacitance of the PANI/0.2 M Cu²⁺ film shows a larger specific capacitance of 618 F g⁻¹, lower resistance and better stability compared with the pure PANI film, although it is reduced to 340 F g⁻¹ after the first 100 cycles. Thus the good capacitive performance demonstrates its potential superiority for supercapacitors.