Microwave selective heating ultrafast construction of coral-like TiO2-MXene /graphene hybrid architectures for high-performance lithium-ion battery

Graphene and MXenes, both as an emerging two-dimensional (2D) material, have become the predominant choice of electrochemical energy electrode materials owing to large surface-area-to-volume ratio and high electrical conductivity. However, severe restacking of such 2D ultrathin nanostructures largely lowers active surfaces and thus constrains their applications. Herein, we develop a microwave selective heating strategy that is highly efficient for ultrafast and scalable fabrication of novel coral-like porous MXene/graphene composite with high-quality graphene and well-dispersed TiO2 nanocrystals. The MXene not only works as a source material but also serves as an excellent microwave absorbent, which leads to that reduction of graphene oxides can be completed within only 10 s under microwave irradiation at a much lower applied power of 200 W than the reported value of 1000 W. Especially the coral-like TiO2-MXene/graphene material with large porosity delivers much higher capacity (356 mAh g−1 at 50 mA g−1) and much better rate capability than those for pure graphene, MXene and other MXene/graphene composites. That is attributed to the composites avoids restacking, assures structural stability, and provides high specific surface area and excellent electrons/ions conductivity. This work provides a new route to large-scale and low-cost production of high-performance electrode materials for lithium-ion battery.