Effect of the Oxidant/Monomer Ratio and the Washing Post-Treatment on Electrochemical Properties of Conductive Polymers

Polyaniline (PANI) and polypyrrole (PPy) were prepared via the chemical oxidative polymerization with various oxidant/monomer initial mole ratios (O/M) in hydrochloric acid aqueous solution and washing with water or ethanol to investigate the effect of the O/M ratio and the washing process on their electrochemical performance as electrode materials for supercapacitors. Their morphologies were characterized with transmission electron microscopy (TEM), and the electrochemical performance of the PANI and PPy electrodes was studied by cyclic voltammogram and galvanostatic charge/discharge tests. It was found that the electrical conductivities and specific capacitances of the polymers were mainly dependent on the O/M ratio. An additional post-treatment of washing was considered as an unfavorable processing with the decrease in yield, conductivity, and capacitance, except for the partial enhancement of the cyclic stabilities. This understanding will lead to a better design of conductive polymer-based electrode materials for supercapacitors.