Ti3C2Tx MXene wrapped, carbon-coated porous Si sheets for improved lithium storage performance

Abstract

Si-based materials have shown great potential as lithium-ion batteries (LIBs) anodes due to their natural reserves and high theoretical capacity. However, the large volume changes during cycles and poor conductivity of Si lead to rapid capacity decay and poor cycling stability, ultimately limiting their commercial applications. Herein, we have skillfully utilized the microporous MCM-22 zeolite as the unique silicon source to produce porous Si (pSi) sheets by a simple magnesiothermic reduction, followed by a carbon coating and further Ti3C2Tx MXene assembly, obtaining the ternary pSi@NC@TNSs composite. In the design, porous Si sheets provide more active sites and shorten Li-ion transport paths for electrochemical reactions. The N-doped carbon (NC) layer serves as a bonding layer to couple pSi and Ti3C2Tx. The conductive network formed by 2D Ti3C2Tx and medium NC layer effectively enhances the overall charge transport of the electrode material, and helps to stabilize the electrode structure. Therefore, the as-made pSi@NC@TNSs anode delivers an improved lithium storage performance, exhibiting a high reversible capacity of 925 mAh/g at 0.5 A/g after 100 cycles. This present strategy provides an effective way towards high-performance Si-based anodes for LIBs.