Polyaniline nanosphere as electrode material for supercapacitor applications

Abstract

The development of efficient electrode material is essential to promote the performance of energy storage devices. Nowadays, polyaniline materials have been widely used as electrodes for supercapacitors due to their outstanding property, however, the poor electrochemical performance of polyaniline-based materials and low stability limit their large-scale application. In this work, polyaniline (PANI) nanospheres have been successfully synthesized at room temperature by the chemical oxidative polymerization of aniline with ammonium persulfate (APS) in aqueous salicylic acid. Chemically synthesized PANI nanospheres were characterized using Ultraviolet Visible spectroscopy (UV-Vis), Thermogravimetric analyzer (TGA), Scanning electron microscopy (SEM), X-ray diffraction analysis (XRD) and Fourier transform of infrared spectroscopy (FTIR). The electrical conductivity of the prepared samples were also studied. The electrochemical performance of PANI nanospheres were tested using cyclic voltammetry (CV) technique in H2SO4 electrolyte. Polyaniline nanospheres were found to exhibit better specific capacitance when compared to bulk polyanilines. Furthermore, the polyaniline nanospheres, with [salicylic acid]/[aniline] molar ratio of 0.8 or 0.16:0.2, showed highest specific capacitance of 137.7 Fg-1 at a scan rate of 250 mVs-1 . Electrical conductivity of polyaniline nanosphere is also better when compared to the bulk polyaniline. Thus, PANI nanosphere is found to be promising material for supercapacitors that can deserve intensive study for further enhancements.