P/N co-doped microporous carbons from H3PO4-doped polyaniline by in situ activation for supercapacitors

P/N co-doped porous carbons have been synthesized by a simple method through direct carbonization of phosphoric acid doped polyaniline. The textural property and the surface chemistry have been investigated by nitrogen sorption and X-ray photoelectron spectra. P/N co-doped carbons exhibit typical microporous characters with a low surface area and a narrow pore size distribution. Interestingly, the concentration and the development of heteroatom-containing surface functionalities are strongly depended on the temperature of heat treatment. Cyclic voltammetry and galvanostatic charge–discharge tests have been used to investigate the capacitive performance of such microporous carbons, which exhibit high specific capacitance (154.4 F g−1) and excellent stability. The improved electrochemical performance is attributed to the combination of the co-doping of heteroatoms (P and N) and micropores generated by the in situ activation of phosphoric acid.