Fabrication of 2D Cu-BDC MOF and its derived porous carbon as anode material for high-performance Li/K-ion batteries

2D Cu-BDC MOF nanosheets were designed and synthesized by controlling the reaction time, and then annealed at different pyrolysis temperatures; the final MOF-derived carbons C500 (Final product at 500 °C) and C700 (Final product at 700 °C) were obtained by acid etching. Both carbon derivatives possessed abundant mesoporous structures which could facilitate ion migration and be conducive to the storage of lithium/potassium ions. C500 and C700 exhibited different dominant kinetic behaviors in lithium ion/potassium ion batteries. C500, which was controlled by diffusion process, showed better performance when used as anode material for lithium-ion batteries (LIBs). The C500 anode exhibited a reversible specific capacity of 690.4 mAhg−1 at a current density of 0.1 Ag−1. Even after 500 cycles at a current density of 5.0 Ag−1, the high specific capacity of 210.3 mAhg−1 was still maintained. C700, which was dominated by surface capacitance contribution, was a superior anode material for potassium-ion batteries (PIBs). The reversible specific capacity of C700 anode was maintained at 286.2 mAhg−1 at the current density of 0.1 Ag−1 after 100 cycles. Even after 500 cycles at a current density of 1.0 A g−1, C700 anode still maintained 170.8 mAhg−1.