▎ 摘　　要

Graphene has showed great promise as supercapacitor electrode materials due to the fast charging/discharging rate, high theoretical surface area and excellent cyclic stability. However, scalable synthesis of graphene, especially with pore architectures, is still a challenge. Herein, we developed a scalable and green method to synthesize the porous graphene nanosheets (PGSs), which involved a liquid-phase exfoliation process carried out in water. PGSs and single-wall carbon nanotubes (SWCNTs) mixed suspension was vacuum filtered to fabricate the PGS@SWCNT composite film (GNCF) for electrode materials. The as-prepared free-standing GNCF electrode exhibits a desirable electrochemical energy storage capability due to the synergistic effect between PGSs and SWCNTs. In addition, the holes out of nanosheets and the pores in plane provide more electrolyte ion transport channels. To assess the practical applications of the GNCF, a flexible symmetric all-solid-state supercapacitor was fabricated. Such a supercapacitor device delivers a specific capacitance of 202.5 F/g at 10 mV/s, along with an outstanding cyclic stability with the capacitance retention of 91.2% over 10,000 cycles. These performances are comparable with those of the graphene-based electrodes prepared by CVD or Hummers' method. These findings provide a cost-effective, environmentally friendly and scalable method for the production of porous graphene nanosheets which can be used in supercapacitors.