Charge storage performance of doped carbons prepared from polyaniline for supercapacitors

Doped carbons have been prepared from polyaniline for supercapacitors. The morphology of samples has been characterized by scanning electron microscope, the surface chemical composition of samples has been investigated by X-ray photoelectron spectroscopy, and the surface area of samples has been calculated by Brunauer-Emmett-Teller measurement. Electrochemical properties have been studied by cyclic voltammograms, galvanostatic charge/discharge, and electrochemical impedance spectroscopy measurements in 6 mol L-1 potassium hydroxide. Their charge storage performance has been evaluated, and the effect of nitrogen atomic functionalities on the pseudocapacitive property has been studied. The experimental results have proved two mechanisms of energy storage in doped carbons: double-layer formation and pseudocapacitance. The overall specific capacitance of doped unactivated carbon is mainly attributed to pseudocapacitance, that of doped activated carbon prepared by physical activation is attributed to the synergic effect of pseudocapacitance and double-layer capacitance, but that of doped activated carbon prepared by chemical activation is mainly attributed to double-layer capacitance.