High capacitance properties of polyaniline by electrochemical deposition on a porous carbon substrate

Electrochemical deposition of polyaniline (PANI) is carried out on a porous carbon substrate for supercapacitor studies. The effect of substrate is studied by comparing the results obtained using platinum, stainless steel and porous carbon substrates. PANI deposited at 100 mV s(-1) sweep rate by potentiodynamic technique on porous carbon substrate is found to possess superior capacitance properties. Experimental variables, namely, concentrations of aniline monomer and H2SO4 Supporting electrolyte are varied and arrived at the optimum concentrations to obtain a maximum capacitance of PANI. Low concentrations of both aniline and H2SO4, which produce PANI at low rates, are desirable. The PANI deposits prepared under these conditions possess network morphology of nanofibrils. Capacitance values as high as 1600 F g(-1) are obtained and PANI coated carbon electrodes facilitate charge-discharge current densities as high as 45 mA cm(-2) (19.8 A g(-1)). Electrodes are found to be fairly stable over a long cycle-life, although there is some capacitance loss during the initial stages of cycling. (c) 2006 Elsevier Ltd. All rights reserved.