Redox-active mesoporous carbon nanosheet with rich cracks for high-performance electrochemical energy storage

Abstract

Construction of ordered mesoporous carbon (OMC) with two-dimensional morphology and rich redox functionalities may offer the possibility for improving the supercapacitive performances of the OMC-based electrode materials in capacity and rate performance. Herein, a simple approach by assembly soluble phenolic resin with surfactant of F127 on a self-made magnesium hydroxide was developed and applied to the fabrication of ordered mesoporous carbon nanosheet (OMCN). The obtained OMCN possesses weak ordered mesoporous structure, nanosheet morphology, large surface area (1376 m2/g vs soft-templated OMC of 522 m2/g), rich cracks and abundant electroactive oxygen functionalities (13.6%). As electrode for supercapacitor, the OMCN exhibits a two times larger capacity than that of OMC (301 F/g vs 151 F/g) and excellent rate performance with capacitance retention of 84% (vs that of OMC of 62%). For aqueous symmetric supercapacitor in 1.0 M Na2SO4, the OMCN based electrode achieves an ultrahigh energy density of 25.3 Wh/kg at power density of 2000 W/kg. As cathode material working on the voltage range of 1.5–4.5 V, OMCN also exhibits a superior surface-driven lithium-ion storage performance including large capacity of 140 mAh/g at 0.5 A/g (vs that of OMC of 7.6 mAh/g), good rate performance and long cycle stability with about 96% capacity retention after 2000 cycles at 2A/g, showing a promising candidate for the electrochemical energy storage.