Coal-Tar-Pitch-Derived Carbon Nanocages for High-Performance Supercapacitors

Hierarchical porous carbons are advanced hosts for electrochemical energy storage. Herein, using inexpensive coal-tar-pitch (Ctp) obtained from coal mining as the precursor of the MgO template method, a series of hierarchical carbon nanocages (CNC) with different specific surface areas, pore volumes, conductivities, and wettabilities were synthesized. The optimized CNC demonstrates outstanding supercapacitor performance, exhibiting a specific capacitance of 236 F g–1 at 1 A g–1 and a capacitance retention of 94.6% cycled at 50 A g–1 for 120,000 charge–discharge cycles in 6 M KOH electrolyte and showing a specific capacitance of 191 F g–1 at 1 A g–1 and a capacitance retention of 84% cycled at 50 A g–1 for 120,000 cycles in 1 M Na2SO4 electrolyte. This study not only provides an advanced hierarchical porous carbon material with excellent supercapacitor performance but also suggests an efficient way for the high-value utilization of Ctp in coal mining.