Facile preparation of MoO3@Mo2CT x nanocomposite with high lithium storage performance by in situ oxidation

In this work, a new MoO₃@Mo₂CT_xnanocomposite was prepared from two-dimensional (2D) Mo₂CT_xMXene byin situoxidization in air, which exhibited wonderful lithium-storage performance as anodes of lithium-ion batteries (LIBs). The precursor Mo₂CT_xwas synthesized from Mo₂Ga₂C by selective etching of NH₄F at 180 °C for 24 h. Thereafter, the Mo₂CT_xwas oxidized in air at 450 °C for 30 min to obtain MoO₃@Mo₂CT_xnanocomposite. In the composite,in situgenerated MoO₃nanocrystals pillar the layer structure of Mo₂CT_xMXene, which increases the interlayer space of Mo₂CT_xfor Li storage and enhances the structure stability of the composite. Mo₂CT_x2D sheets provide a conductive substrate for MoO₃nanocrystals to enhance the Li⁺accessibility. As anodes of LIBs, the final discharge specific capacity of the MoO₃@Mo₂CT_xcomposite was 511.1 mAh g^-1at a current density of 500 mA g^-1after 100 cycles, which is about 36.7 times that of pure Mo₂CT_xMXene (13.9 mAh g^-1) and 3.2 times that of pure MoO₃(159.9 mAh g^-1). In the composites, both Mo₂CT_xand MoO₃provide high lithium storage capacity and can enhance the performance of each other. Moreover, this composite can be made by a facile method ofin situoxidation. Therefore, the MoO₃@Mo₂CT_xMXene nanocomposite is a promising anode of LIB with high performance.