Comparative Study on Supercapacitive Performances of Hierarchically Nanoporous Carbon Materials With Morphologies From Submicrosphere to Hexagonal Microprism.

Hierarchically nanoporous carbon materials (HNCMs) with well-defined morphology and excellent electrochemical properties are promising in fabrication of energy storage devices. In this work, we made a comparative study on the supercapacitive performances of HNCMs with different morphologies. To this end, four types of HNCMs with well-defined morphologies including submicrospheres (HNCMs-S), hexagonal nanoplates (HNCMs-N), dumbbell-like particles (HNCMs-D), and hexagonal microprisms (HNCMs-P) were successfully synthesized by dual-template strategy. The relationship of structural-electrochemical property was revealed by comparing the electrochemical performances of these HNCMs-based electrodes using a three-electrode system. The results demonstrated that the HNCMs-S-based electrode exhibited the highest specific capacitance of 233.8 F g at the current density of 1 A g due to the large surface area and well-defined hierarchically nanoporous structure. Moreover, the as-prepared HNCMs were further fabricated into symmetrical supercapacitor devices (HNCMs-X//HNCMs-X) using KOH as the electrolyte and their supercapacitive performances were checked. Notably, the assembled HNCMs-S//HNCMs-S symmetric supercapacitors displayed superior supercapacitive performances including high specific capacitance of 55.5 F g at 0.5 A g, good rate capability (retained 71.9% even at 20 A g), high energy density of 7.7 Wh kg at a power density of 250 W kg, and excellent cycle stability after 10,000 cycles at 1 A g. These results further revealed the promising prospects of the prepared HNCMs-S for high-performance energy storage devices.