Porous carbon derived from metal-organic framework@graphene quantum dots as electrode materials for supercapacitors...

The C@GQD composite was prepared by the combination of metal-organic framework (ZIF-8)-derived porous carbon and graphene quantum dots (GQDs) by a simple method. The resulting composite has a high specific surface area of 668 m² g^-1 and involves numerous micro- and mesopores. As a supercapacitor electrode, the material showed an excellent double-layer capacitance and a high capacity retention of 130 F g^-1 at 2 A g^-1. The excellent long-term stability was observed even after ∼10 000 charge-discharge cycles. Moreover, the composite as an anode material for a lithium-ion battery exhibited a good reversible capacity and outstanding cycle stability (493 mA h g^-1 at 100 mA g^-1 after 200 cycles). The synergistic effect of a MOF-derived porous carbon and GQDs was responsible for the improvement of electrochemical properties.