Fabrication of microporous and mesoporous carbon spheres for high-performance supercapacitor electrode materials

Abstract

Summary: Microporous and mesoporous carbon spheres (CSs) were fabricated using resorcinol and formaldehyde as precursors in the presence of Pluronic F127 as porogen and KOH as the active agent. The textural characteristic and morphology were characterized by scanning electron microscopy, transmission electron microscopy, and N2 adsorption/desorption techniques. Pluronic F127 played an important role for generating mesopores, while KOH activation brought abundant micropores and resulted in a combined microporous and mesoporous structure of the CSs. The results showed that a typical sample (denoted as CS-F-K) possessed a spherical shape, with a high specific surface area of 735.4m2/g, large pore volume of 0.622cm3/g, and combined microporous and mesoporous structure, which endowed CS-F-K good electrochemical performance with a specific capacitance of 182F/g under a current density of 0.5A/g, remarkable rate performance, and long-term cycling stability. After 1000 cycles at 3A/g, CS-F-K electrode can still remain the specific capacitance of 154.8F/g with a retention of 98.9%. The excellent electrochemical performance of CS-F-K was mainly attributed to the micro-mesoporous structure, which promoted the ion accumulation on the electrode surface and facilitated fast ion transportation.