Pore structure regulation of hierarchical porous carbon derived from coal tar pitch via pre-oxidation strategy for high-performance supercapacitor.

Carbon materials with rational pore structure have attracted tremendous attention in high-performance supercapacitor applications. However, designing and constructing such carbon materials with excellent performances via a simple and low-cost route is still a challenge. Herein, the nitrogen self-doped oxygen-rich hierarchical porous carbons (OTS-PC) derived from coal tar pitch are constructed via a facile strategy of air pre-oxidation-activation. The air pre-oxidation treatment can effectively regulate the small-sized mesopore structure (2-4 nm) of samples. The optimal OTS-PC sample exhibits a high specific capacitance of 298 F g at 0.5 A g, and delivers a high energy density of 14.9 Wh kg at a power density of 0.15 kW kg with remarkable cycling stability in KOH aqueous electrolyte. This excellent electrochemical performance is attributed to its ultrahigh specific surface area (SSA, 2941 m g), huge total pore volume (V, 1.9 cm g), rational pore structure and reasonable heteroatom configuration, which ensure sufficient charge storage, rapid electrolyte ions diffusion, as well as the contributed pseudocapacitance. This research not only offers a facile route for high-value utilization of coal tar pitch but also provides the cost-effective and excellent porous carbons for supercapacitor with high performance.