Preparation of nitrogen-doped pitch-based carbon materials for supercapacitors

Coal tar pitches (CTP) are used as precursor of electrode material because of their low cost and high carbon yield. In this study, CTP-based activated carbon materials (CACs) with high capacitance for supercapacitors were prepared by doping elemental N with co-carbonization of CTP and melamine. The electrochemical performance and textural characterization of CACs were investigated by constructing a single electrode capacitor in a 6   M KOH electrolyte, N 2 adsorption, scanning electron microscopy, and XPS. Results show that CACs with mass proportion of melamine and CTP being 1:5 possess a surface area of 2573   m 2   g −1 , with mesopore volume accounting for 56% of the total volume. After co-carbonization, N content on the surface of the CACs increased by 134% compared to that of undoped activated carbons. Their capacitance reached up to 228   F   g −1 at a current density of 1   A   g −1 . The high electrochemical performance of the CACs is attributed to its additional pseudo-capacitance and high surface area. The specific capacitance still possessed 94.2% retention after 1000 cycles, indicating good cycle stability.