Constructing MOF-derived CoP-NC@MXene sandwich-like composite by in-situ intercalation for enhanced lithium and sodium storage

The development of dual-function anode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) is exceedingly essential. Herein, with rationally designed hierarchical metal-organic framework (MOF)@MXene as a precursor, a novel sandwich-like CoP-NC@Ti₃C₂T_x composite has been successfully fabricated by the following phosphorization reaction. As anode material for LIBs, the CoP-NC@Ti₃C₂T_x composite exhibits remarkable electrochemical performance with high-rate capability (147.8 mAh g⁻¹ at 2000 mA g⁻¹; 245.6 mAh g⁻¹ at 100 mA g⁻¹) and ultralong cycling life (2000 cycles with a capacity retention over 100%). For SIBs, it delivers a discharge capacity of 101.6 mAh g⁻¹ at a current density of 500 mA g⁻¹ after 500 cycles. The well-designed sandwich-like composite effectively supports the easy access to electrolyte, facilitate the Li/Na ion transportation, and protect the active material from pulverization upon long cycling. In addition, the electrochemical reaction kinetics and Li-migration kinetics of the CoP-NC@Ti₃C₂T_x composite have been pioneeringly illuminated by pseudocapacitive behavior calculation and density functional theory (DFT) computations, respectively. This work sheds light on the rational design and development of MOF/MXene-derived dual-function anode materials for Li/Na-storage.