Preparation and Properties of Poly-2,5-dihydroxyaniline/Activated Carbon Composite Electrode

Poly-2, 5-dimethoxyaniline (PDMA) coating was successfully prepared by electrochemical method on the surface of active carbon (AC) electrodes in oxalic acid aqueous solution. The resulted coating was hydrolyzed to produce poly-2,5-dihydroxyaniline (PDHA) to enhance the capacitance of the composite electrode. Scanning electron microscope (SEM), cyclic voltammetry (CV), galvanostatic charge/discharge test, and electrochemical impedance spectroscopy (EIS) were used to investigate the properties of these electrodes. A comparative analysis on the electrochemical properties of bare-carbon electrode was also conducted under similar conditions. The specific capacitance of the PDHA/AC composite electrode was 947.04 F•g-1 between 0.0 and 1.0 V at a current density of 3.0 mA•cm-2 in 0.5 M H2SO4 electrolyte. The capacitance retention of composite electrode was about 89.2% during 700 charge-discharge cycles.