Continuous and Scalable Manufacture of Coal-Derived Hierarchical Porous Carbon Dominated with Mesopores for High Rate-Performance Supercapacitors

The continuous and scalable manufacture of porous carbon electrode materials with controlled pore architecture holds paramount importance in the development of efficient and sustainable energy storage systems. Herein, a green and industrially feasible physical activation strategy was proposed to produce heteroatom self-doped hierarchical porous carbons (HPCs) by using polyvinyl butyral (PVB) as a sacrificial template and cross-linking agent and low-rank coal as a low-cost precursor. The optimal HPC-20 has highly interconnected multiscale pore structure, large specific surface area, and heteroatom-enriched surfaces. The synergistic effect of these advantages provides HPC-20 with a variety of benefits, including fast charge/discharge rates and abundant energy storage sites. Specifically, HPC-20 exhibited an appreciable specific capacitance of 304 F g–1 at 0.5 A g–1 and an excellent rate performance (capacitance retention of 65.8% at 50 A g–1). Furthermore, the symmetric supercapacitor achieved a maximum energy density of 23.1 W h kg–1 at a power density of 450 W kg–1 in 1 M Na2SO4 electrolytes. This work proposes an approach for the large-scale production of porous carbon with a controllable pore structure from low-rank coal.