Electrochemical polymerization of polyaniline doped with Zn2+ as the electrode material for electrochemical supercapacitors

Polyaniline doped with Zn2+ (PANI/Zn2+) films was synthesized by cyclic voltammetric method on stainless steel mesh substrates in 0.2 mol L−1 aniline and 0.5 mol L−1 sulfuric acid electrolyte with various concentrations of zinc sulfate (ZnSO4·7H2O). The structure and morphology of PANI and PANI/Zn2+ films were characterized by Fourier transform infrared, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy techniques, respectively. The electrochemical properties of PANI and PANI/Zn2+ films were investigated by cyclic voltammetry, galvanostatic charge–discharge test, and electrochemical impedance spectroscopy in 0.5 mol L−1 H2SO4 electrolyte in a three-electrode system. The results show that the surface morphology of PANI/Zn2+ is more rough than that of pure PANI. The specific capacitance of the PANI/Zn2+ film displays a larger specific capacitance of 738 F g−1, lower resistance, and better stability as compared with the pure PANI film. Thus, good capacitive performance demonstrates its potential superiority for supercapacitors.