二维层状负极材料MXene具有电子电导率和锂离子扩散速率高，倍率性能和循环性能优异等优点，但较低的比容量限制了其能量密度；硅负极拥有4200mAh/g的高比容量，然而巨大的体积效应和SEI膜不稳定等问题导致其循环性能较差。本研究提出将纳米硅和多孔碳插入MXene原子层构建MXene/Si@C复合材料体系，利用其协同效应提高材料的电化学性能：通过硅、碳前驱体与MXene原子层表面羟基等结合，消除有害官能团的同时增加活位点，极大地提高材料的比容量；利用MXene原子层间距及层间张力抑制硅在嵌锂时垂直方向的体积膨胀，利用MXene层间的多孔碳缓冲硅在水平方向的体积膨胀，从而提高SEI膜的稳定性并显著改善材料的循环性能；利用MXene和多孔碳形成高效导电网络来提高材料的电子电导率，通过硅纳米化和扩大MXene层间距提升材料的锂离子扩散速率。最终获得高比容量、高倍率性能和长寿命的锂离子电池负极材料。

The anode material, two-dimensional layered MXene, has high electron conductivity and lithium ion diffusion rate, excellent rate capability and cycle ability, however its energy density is limited by the specific capability. The silicon material exhibits a high specific capacity of 4200 mAh/g, but its cycling performance is poor due to the serious volume effect and SEI film instability. In this study, a composite material system MXene/Si@C is constructed with the insertion of nano-silicon and porous carbon into the MXene atomic layer, and the electrochemical properties of the material can be enhanced by the composites synergistic effect. By combining the precursors of silicon and carbon with the hydroxyl groups on the surface of the MXene atomic layer, the harmful functional groups can be eliminated and the active sites can be increased, greatly improving the specific material capacity. The volume expansion of silicon in the vertical direction during lithium intercalation can be suppressed with MXene interlayer spacing and interlayer tension, and the expansion in the horizontal direction can be buffered by the porous carbon in the MXene interlayer, resulting in significantly increasing the stability of SEI film and the material cycling performance. An efficient conductive network consisted of MXene and porous carbon can be gained to improve the electronic conductivity of the material, and the lithium ion diffusion rate will also be improved by silicon nanocrystallization and the increase of MXene interlayer spacing. From the above, the high specific capacity, high rate capability and long life anode composite material is obtained.