Effect of Nafion on the preparation and capacitance performance of polyaniline

With manganese dioxide (MnO2) as the oxidant, perfluorinated sulfonic acid ion exchange resin (Nafion) as the doping agent and emulsifier, Nafion doped polyaniline (PANI-Nafion) was prepared by emulsion polymerization method. Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were carried out to characterize the structure and morphology of PANI-Nafion. Symmetric redox supercapacitor was assembled with PANI-Nafion as active electrode material and 1.0 mol L−1 H2SO4 aqueous solution as electrolyte. The electrochemical characteristics of these supercapacitors were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge tests. These results show that the diameter of PANI-Nafion nanofiber is about 30 ∼ 40 nm and the pores between PANI-Nafion composite materials are distributed uniformly. The specific capacitance of PANI-Nafion electrode is about 385.3 F g−1, which is higher than that of undoped PANI (235.8 F g−1). After 1000 charge/discharge cycles the specific capacitance of PANI-Nafion electrode is 272.4 F g−1, its capacity retention is 70.7%, which is significantly better than that of PANI electrode materials.