▎ 摘　　要

A facile hydrothermal and freeze-drying approach was employed to prepare N, B co-doped graphene gel (N/BGR). Positively charged [BMIm][BF4] ionic liquid as N/B source and negatively charged graphene oxide (GO) as graphene precursor are capable of combining and self-assembly by electrostatic force. The high doped concentrations of N and B elements are 8.16 at% and 6.31 at% (total 14.47 at%). The N/BGR was fabricated as electrode material in the three-electrode system. The as-prepared N/BGR-2 electrode could achieve a specific capacitance of 133.6 F/g at 0.5 A/g. The N/BGR electrode presented enhanced capacitance performance. Compared with the specific capacitance of pure GR at the same current density of 0.5 A/g, the specific capacitances of N/BGR-2 and N/BGR-1 have increased by 68.5 % and 49.4 %. The enhanced capacitance of N and B co-doped graphene could be attributed to the promotion of rapid electron migration and charge transfer and production of redox active sites that provide pseudocapacitance. In addition, N/BGR-2 electrode exhibits good cycling durability with the capacity retention of 93.2 %% after 1500 cycles at a high current density of 10 A/g. Those provide a high co-doped content fabrication strategy for high-performance supercapacitors carbon-based electrode materials.