Rational design of dense microporous carbon derived from coal tar pitch towards high mass loading supercapacitors.

Schematic illustration of the preparation of dense microporous carbons. [Display omitted] • The dense microporous carbons were prepared by a universal and facile strategy of pre-oxidation carbonization–activation. • The prepared microporous carbons not only possess well-developed porous structure but also have a large packing density. • The optimum microporous carbon shows high specific capacitance and excellent rate performance. • This work offers a good cost-efficiency strategy to prepare electrode materials with prospects for practical applications. The compact carbon materials with huge specific surface area (SSA) and proper pore structure are highly desirable towards high-performance supercapacitors at the cell level. However, to well balance of porosity and density is still an on-going task. Herein, a universal and facile strategy of pre-oxidation–carbonization–activation is employed to prepare the dense microporous carbons from coal tar pitch. The optimized sample POCA800 not only possesses a well-developed porous structure with the SSA of 2142 m2 g−1 and total pore volume (V t) of 1.540 cm3 g−1, but also exhibits a high packing density of 0.58 g cm−3 and proper graphitization. Owing to these advantages, POCA800 electrode at areal mass loading of 10 mg cm−2 shows a high specific capacitance of 300.8 F g−1 (174.5 F cm−3) at 0.5 A g−1 and good rate performance. The POCA800 based symmetrical supercapacitor with a total mass loading of 20 mg cm−2 displays a large energy density of 8.07 Wh kg−1 at 125 W kg−1 and remarkable cycling durability. It is revealed that the prepared density microporous carbons are promising for practical applications. [ABSTRACT FROM AUTHOR]