Ordered hierarchical mesoporous/microporous carbon with optimized pore structure for supercapacitors

Abstract

A series of ordered mesoporous/microporous carbon materials with controllable micropore size was prepared from chlorination of ordered mesoporous titanium carbide/carbon composites obtained by an evaporation induced self-assembly approach. The proportion of micropores can be tuned easily by changing the Ti content in the parent TiC/C composites in order to study the effect of micropore content on rate capability and specific capacitance. Under the optimized condition, an optimal mesoporous/microporous carbon with moderate micropores (52.4% in volume) was obtained. It has a high surface area (1698 m² g⁻¹) and a large pore volume (1.17 cm³ g⁻¹), with the mesopore size centered at 4.4 nm, and micropore sizes of 0.52, 0.76 and 1.35 nm. It exhibits a high capacitance of 132 F g⁻¹ at the current density of 500 mA g⁻¹ and good rate capability with capacitance retention of 79% at a scan rate of 2000 mV s⁻¹vs. 20 mV s⁻¹ in nonaqueous electrolyte, and also shows a good cycling stability with capacitance retention of 84% over 5000 cycles.