Facile preparation of MoO 3 @Mo 2 CT x nanocomposite with high lithium storage performance by in situ oxidation.

In this work, a new MoO 3 @Mo 2 CT x nanocomposite was prepared from two-dimensional (2D) Mo 2 CT x MXene by in situ oxidization in air, which exhibited wonderful lithium-storage performance as anodes of lithium-ion batteries (LIBs). The precursor Mo 2 CT x was synthesized from Mo 2 Ga 2 C by selective etching of NH 4 F at 180 °C for 24 h. Thereafter, the Mo 2 CT x was oxidized in air at 450 °C for 30 min to obtain MoO 3 @Mo 2 CT x nanocomposite. In the composite, in situ generated MoO 3 nanocrystals pillar the layer structure of Mo 2 CT x MXene, which increases the interlayer space of Mo 2 CT x for Li storage and enhances the structure stability of the composite. Mo 2 CT x 2D sheets provide a conductive substrate for MoO 3 nanocrystals to enhance the Li + accessibility. As anodes of LIBs, the final discharge specific capacity of the MoO 3 @Mo 2 CT x 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 Mo 2 CT x MXene (13.9 mAh g -1 ) and 3.2 times that of pure MoO 3 (159.9 mAh g -1 ). In the composites, both Mo 2 CT x and MoO 3 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 MoO 3 @Mo 2 CT x MXene nanocomposite is a promising anode of LIB with high performance.