A facile one-pot fabrication of flowerlike graphene-based particles for electric double-layer capacitors

Flowerlike graphene-based particles had been successfully synthesized from the suspension of graphene oxide (GO) in the aqueous solution of sucrose by one-pot hydrothermal carbonization approach. Porous carbon from sucrose prompted the evolution of graphene from flat-shaped to flowerlike curved morphology, which was confirmed by the observation of scanning electron microscopy and transmission electron microscopy. The graphene-based particles possess large pore volume (0.69 cm3 g−1) and surface area (470.5 m2 g−1), which is about 6 times greater than that of carbonized graphene sheets (79.2 m2 g−1). Electrochemical investigation indicated that the specific capacitance of the particles reached 162 F g−1 at current density of 0.1 A g−1 in 30 wt% KOH aqueous electrolytes and the capacitance maintenance achieved 90% as the current density enlarged 50 times. The keys to the ideal capacitive performance are the abilities to make full utilization of specific surface area of graphene and ensure a quick kinetic process for the diffusion of ions within curved graphene particles with considerable open edges.