Introducing catalytic gasification into chemical activation for the conversion of natural coal into hierarchically porous carbons with broadened pore size for enhanced supercapacitive utilization

Abstract

Focusing on engineering the pore structure of porous carbons for enhanced supercapacitive performances, a new type of coal derived hierarchically porous carbon which is synthesized by introducing a catalytic gasification mechanism into an often-utilized chemical activation process is demonstrated. Such a strategy skillfully employs the catalytic effects of the minerals in natural coal on the etching reaction between CO2 molecules and carbon framework, which easily widen the pore size of well-developed micropores, thereby yielding a hierarchical pore configuration with simultaneously high surface area, large pore volume as well as broadened pore size distribution. The enhanced pore development mechanism is elucidated by a series of control experiments and thermogravimetric analysis. Evaluated as supercapacitor electrode materials, the resulting HPC exhibits state-of-the-art supercapacitive performances in both aqueous and non-aqueous electrolytes, particularly the superior rate capabilities, which highlights the favorable role of broadened pore configuration in facilitating electrolyte ion transfer and storage. Combining with the naturally abundant carbon resource and easily-implemented preparation craft, the as-obtained coal transferred hierarchically porous carbons hold great potentials for industrial production and supercapacitor applications.