Electron oriented injection TiSe2–C laminated heterojunctions derived from terminal functionalized MXene for high-rate sodium ion storage

Herein, TiSe2-C laminated heterojunction in-situ derived from halogen ion（-Cl, -F）terminal functionalized Ti3C2Tx MXene was prepared by the solid-state reaction. Functional Precursor of Cl-enriched MXene was synthesized by chloride molten etching method, high-crystalline TiSe2-C laminated heterojunction was obtained after the selenylation process. For F-enriched MXene, abundant TiO2 nanoparticles could be acquired besides TiSe2-C lamination. Based on DFT calculation results, byproduct TiO2 and amorphous carbon can continuously inject electrons to TiSe2, owing to the discrepancy of work functions. Excellent charge-carrier transportation peculiarity gives TiSe2-C lamination heterojunction excellent electrochemical performances and can also accelerate the kinetic process. Among them, TiSe¬2-Cl can demonstrate a reversible capacity of 369.14 mAh g-1 at the current of 1 A g-1, and even keep a high rate capacity 372.26 mAh g-1 at 5 A g-1. This study provides a new idea to synthesize MXene derivatives for high performance sodium ion batteries anode materials.