Fabrication of N/O co-doped porous carbon derived from coal liquefaction pitch for high-performance supercapacitors

Transforming coal liquefaction pitch (CLP) from hazardous waste to high-value carbon precursors is a vital research avenue toward efficient utilization of coal. Here, a synergistic activation strategy is proposed, in which C 2 H 10 N 6 ·H 2 CO 3 is employed as the nitrogen source and couple with KCl to assist HCOOK activation, enabling the fabrication of N/O co-doped porous carbon from CLP. Systematic studies were executed to elucidate the influence of the nitrogen source and activator on the structural properties and electrochemical performance of the as-prepared porous carbon materials. The results indicate that synergistic effects originating from the pyrolysis interaction of C 2 H 10 N 6 ·H 2 CO 3 and HCOOK, the templating function of KCl, and the eutectic melting behavior of the mixed salts collectively facilitate the formation of a three-dimensional thin-walled honeycomb structure. Concurrently, N/O co-doping enhances interfacial reaction kinetics through interfacial activation and charge-transfer modulation. These multiscale cooperative effects ultimately enable the formation of a micropore-dominated porous architecture with small mesoporous contributions. This architecture maintains a high surface area while facilitating ion transport, thereby delivering superior electrochemical performance. The optimized NPC-2-2 sample achieves an ultrahigh specific surface area of 2259.69 m 2 /g, a microporosity of 86.54 %. Electrochemical measurements further reveal that NPC-2–2 delivers promising electrochemical energy storage performance and remarkable cycling stability, achieving a specific capacitance of 314.5F/g at 0.5 A/g, with a capacitance retention of 89.27 % after 10,000 cycles. The present findings afford feasible strategies for the high-value utilization of CLP and efficient fabrication of porous carbon materials.