Abstract:

Polyaniline (PANI) nanomaterials doped with three different sulfonic acid surfactants (perfluorinated sulfonic acid ion exchange resin (Nafion), sodium dodecyl sulfate (SDS), and sodium dodecyl benzene sulfonate (SDBS)) were prepared using an emulsion polymerization method with manganese dioxide (MnO₂) as the oxidant. The structure and morphology of the products were studied by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). Symmetric redox supercapacitor was assembled with doped PANI as the active electrode material. The electrochemical performances of the materials were evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge tests. These results suggest that the introduction of surfactant is beneficial for the formation of a fiber structure and increases the dispersion of PANI. A PANI-Nafion network with distributed porosity and average diameters of 30-40 nm is obtained. The specific capacitances of PANI-Nafion, PANI-SDS, and PANI-SDBS electrodes at 0.1 A·g^-1 are 385.3, 359.7, and 401.6 F·g^-1, respectively. Among these electrodes PANI-Nafion delivers the best cycle performance, maintaining 70.7% of its initial capacitance after 1000 cycles.

Key words: Polyaniline, Organic sulfonic acid, Emulsion polymerization, Nanofiber, Supercapacitor