The Effect of a Small Amount of Water on the Structure and Electrochemical Properties of Solid-State Synthesized Polyaniline

A series of polyaniline (PANI) salts were synthesized with the presence of a small amount of water varying from 0 to 1 mL at the beginning of solid-state polymerization. The structure and morphology of the samples were characterized by fourier transform infrared (FTIR) spectra, ultraviolet-visible (UV-Vis) absorption spectra, X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrochemical performances of the products were investigated by galvanostatic charge-discharge, cyclic voltammetry, cycling stability and electrochemical impedance spectroscopy (EIS). The results showed that the amounts of water can affect the oxidation degree, conjugate level and crystallinity of PANI salts. All PANI salts showed spherical morphology with the diameter of about 60 nm as shown by TEM. The electrochemical tests showed the highest specific capacitance value 593.3 Fg in 1 M H2SO4 for PANI prepared with the addition of 0.5 mL of water at the beginning of solid-state polymerization.