Effect of nitrogen in carbon electrode on the supercapacitor performance

Porous carbons enriched in nitrogen (from 1.9 to 7.2 wt%) substituted for carbon in the network have been tested for supercapacitor application. Voltammetry, galvanostatic and impedance spectroscopy measurements clearly show a beneficial effect of nitrogen on the capacitance behavior in acidic and organic medium. For a series of carbons with similar microtextural characteristics (SBET about 800 m2/g, micropore fraction 0.84-0.93) a perfect correlation of specific capacitance and nitrogen content is reported, especially, for acidic electrolyte. The enhancement of surface area to 1400 m2/g with a moderate nitrogen content (2.6 wt%) leads to a superior capacitance behavior.