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

In this work, a new MoO3@Mo2CTx nanocomposite was prepared from two–dimensional (2D) Mo2CTx MXene by in situ oxidization in air, which exhibited wonderful lithium-storage performance as anodes of lithium–ion batteries (LIBs). The precursor Mo2CTx was synthesized from Mo2Ga2C by selective etching of NH4F at 180 °C for 24 h. Thereafter, the Mo2CTx was oxidized in air at 450 °C for 30 min to obtain MoO3@Mo2CTx nanocomposite. In the composite, in situ generated MoO3 nanocrystals pillar the layer structure of Mo2CTx MXene, which increases the interlayer space of Mo2CTx for Li storage and enhances the structure stability of the composite. Mo2CTx 2D sheets provide a conductive substrate for MoO3 nanocrystals to enhance the Li+ accessibility. As anodes of LIBs, the final discharge specific capacity of the MoO3@Mo2CTx composite was 511.1 mAh g–1 at a current density of 500 mA g–1 after 100 cycles, which is about 36.7 times that of pure Mo2CTx MXene (13.9 mAh g–1) and 3.2 times that of pure MoO3 (159.9 mAh g–1). In the composites, both Mo2CTx and MoO3 provide high lithium storage capacity and can enhance the performance of each other. Moreover, this composite can be made by a facile method of in situ oxidation. Therefore, the MoO3@Mo2CTx MXene nanocomposite is a promising anode of LIB with high performance.