In Situ Intercalating Expandable Graphite for Mesoporous Carbon/Graphite Nanosheet Composites as High‐Performance Supercapacitor Electrodes

Abstract

Mesoporous-carbon-coated graphite nanosheet (GNS@MC) composites have been synthesized by the intercalation of resol prepolymer into the interlayers of expandable graphite (EG) under vacuum-assisted conditions, followed by the exfoliation of EG through in situ polymerization, the growth of resol under hydrothermal conditions, and carbonization under Ar. The GNS@MC composites exhibit enhanced capacitive performance compared to mesoporous carbon (MC), microwaved EG after thermal treatment (T-EG), and the physical mixture of MC and T-EG (MC+T-EG). In particular, the GNS@MC-35-800 composite carbonized at 800 °C, which has a graphite-nanosheet content of 35 % and a Brunauer-Emmett-Teller surface area (S(BET) ) of 432.3 m(2) g(-1) , exhibits the highest capacitance of 203 F g(-1) at 1 A g(-1) in 6 M KOH electrolyte. Furthermore, the GNS@MC-35-800 composite exhibits a good cyclic stability with 95 % capacitance retention and a high columbic efficiency of 99 % after 5000 cycles. The energy density of the symmetric supercapacitor GNS@MC-35-800/GNS@MC-35-800 achieved was as high as 11.5 Wh kg(-1) at a high power density of 10 kW kg(-1) . This good performance is attributable to the GNSs in the GNS@MC composite facilitating electron transport owing to its excellent conductivity; moreover, the MC in GNS@MC favors the rapid diffusion of ions by providing low-resistance pathways. The GNS@MC composite may find application in high-performance energy storage and conversion devices.

Isolated Boron and Nitrogen Sites on Porous Graphitic Carbon Synthesized from Nitrogen‐Containing Chitosan for Supercapacitors

“…indicated that porous graphene with a high surface area has good storage properties 15. We also synthesized a series of carbon materials, such as porous graphitic carbon and mesoporous carbon/graphite sheet composites, which exhibited high energy and power densities 16–18. All these results prove that a porous graphitic structure is desirable for achieving a high capacitance of carbon materials.…”

From graphite to porous graphene-like nanosheets for high rate lithium-ion batteries

“…Expandable graphite (EG) is derived from NG after a simple treatment; as EG has a larger interlayer distance than NG, some functional composites can be introduced into the interlayer of NG [42,43]. Based on these considerations, in a previous study, we synthesized mesoporous carbon/graphite nanosheet composites by intercalating resol prepolymer into the EG interlayer, followed by the exfoliation of EG through in situ polymerization and carbonization processes [44]. Along with the need to enhance the LIB specific capacity, cycling life, and rate capability, simplifying the synthesis and further broadening the application of the graphite derivate are still some of the major challenges in the synthesis of electrode anode materials for the next-generation of LIBs.…”

Molybdenum-doped mesoporous carbon/graphene composites as efficient electrocatalysts for the oxygen reduction reaction

“…Mesoporous carbon (MC) materials with abundant mesoporous tunnels could form spatial structure to improve stability, electroconductibility and electrolyte diffusion of the graphene nanosheets. 26 Herein, we demonstrate a novel and effective soft template strategy for the in situ fabrication of molybdenum-doped mesoporous carbon/graphene composites (Mo-doped MCG). The soft template to prepare mesoporous carbon procursor of resol prepolymer is triblock copolymer Pluronic F127.…”