Pseudocapacitance of Microporous Carbon/Polyaniline Composites

Abstract

High capacity (>200 F/g) supercapacitor electrodes have been fabricated by blending high surface area microporous carbon and polyaniline. The incorporation of a conducting polymer is expected to stabilize the microporous graphitic layers to form a conductive porous composite to increase the capacitance. Well-organized nano- and micropores are believed to facilitate rapid ion diffusion especially when the micropore size is comparable to the ionic radii in the electrolyte solution thereby greatly boosting the capacitance. The initial capacitance of ~110 F/g of the microporous carbon network was found to increase to ~224 F/g (>100% increase) after the incorporation of polyaniline in the 1 M H₂SO₄ aqueous electrolyte. The non-linear behavior in the charge/discharge galvanostatic curve and the appearance of additional redox peaks in the capacitance-voltage curves confirm the presence of pseudocapacitance in the microporous carbon/ polyaniline composite in addition to the electrical double layer capacitance of pristine microporous carbon. The composite material shows the capacitance retention percentage over 80% after 1000 cycles implying a promise for novel supercapacitors with long-lasting ultra-high capacitance and power density.