Porous Si decorated on MXene as free-standing anodes for lithium-ion batteries with enhanced diffusion properties and mechanical stability

Silicon is an ideal anode candidate for next-generation lithium-ion batteries (LIBs) due to its high specific capacity, low working potential and abundant sources. However, its practical application is seriously hindered by its huge volume expansion, which leads to the destruction of the electrode structure and the short cycle life. Herein, we fabricated flexible self-supporting binder-free porous silicon/MXene-2:1 composite film (pSi/MXene-2:1 film) as anode for LIBs by vacuum filtration. The pSi possesses sheet-shape resulting from layered montmorillonite, which is beneficial to shorten ion transport length. Furthermore, the pSi/MXene-2:1 film possesses excellent mechanical flexibility and the voids in the structure can well accommodate the volume expansion during cycling. Benefitting from these advantages, the pSi/MXene-2:1 film anode shows steady cycling performance with 1039.3 mAh/g at 500 mA g−1 after 200 cycles and excellent rate performance with 840.3 mAh/g at 5 A/g. Furthermore, a high reversible capacity of 1201 mAh/g can be obtained at 1 A/g for pSi/MXene-2:1||LiFePO4 full cell. This work provides a strategy to fabricate high-capacity and long-cycle self-supporting silicon-based anodes for flexible LIBs.