▎ 摘　　要

Co-MOF two.dimensional nanosheets were first grown on a carbon cloth by solution method, and MOF-derived porous carbon nanosheets were obtained after high temperature annealing and etching process. Co-MOF derived porous carbon nanosheets/carbon cloths (CNSs/CC) was used as the carbon. based framework, and highly active nitrogen.doped graphene quantum dots (N-GQDs) were loaded by electrochemical deposition to prepare hier. archical porous structures N-GQD/CNS/ CC composite material as electrode material for supercapacitors. The N-GQD/CNS/CC electrode, as a self-supporting and adhesive. free electrode, delivered a specific capacitance of 423 F.g(-1) at 1 A.g(-1). According to the mechanism of energy storage and capacitance contribution, the N-GQD/CNS/CC composite is an ideal supercapacitor electrode material with high capacitance, due to synergetic effect between CNS grown in situ on carbon fiber with high double. layer capacitance and N-GQDs loaded on the surface with high pseudo. capacitance. The highly conductive, hierarchical porous structure of the electrode material is beneficial to the electron transport and the diffusion of electrolyte ions, which presents good kinetic performance, high rate perfor. mance and rapid charge. discharge capability. A symmetrical supercapacitor based on N. GQD/CNS/CC electrode exhibited a high energy density of 250 W.kg(-1) at power density of 7.9 Wh.kg(-1), while the capacitance retention after 10 000 cycles reached 91.2%, which indicates that the N-GQD/CNS/CC composite is an all-carbon electrode material with stable electrochemical performance and high capacitance performance.