Facile and rapid synthesis of highly crumpled graphene sheets as high-performance electrodes for supercapacitors

Highly crumpled graphene sheets (HCGSs) have been prepared by a facile and rapid route through freezing a chemically reduced graphene oxide aqueous suspension with liquid nitrogen. The porous and highly crumpled graphene structure with a large surface area and pore volume facilitates fast ionic transport within the electrode while preserving excellent electrical conductivity and thus endows HCGSs with excellent electrochemical properties. As the electrodes for supercapacitors, the HCGSs exhibit high specific capacitance (259 F g(-1)), excellent rate capability and cycling stability (93% retention after 5000 cycles).