Ti₃Si_0.75Al_0.25C₂ Nanosheets as Promising Anode Material for Li-Ion Batteries

Herein we report that novel two-dimensional (2D) Ti₃Si_0.75Al_0.25C₂ (TSAC) nanosheets, obtained by sonically exfoliating their bulk counterpart in alcohol, performs promising electrochemical activities in a reversible lithiation and delithiation procedure. The as-exfoliated 2D TSAC nanosheets show significantly enhanced lithium-ion uptake capability in comparison with their bulk counterpart, with a high capacity of ≈350 mAh g^-1 at 200 mA g^-1, high cycling stability and excellent rate performance (150 mAh g^-1 after 200 cycles at 8000 mA g^-1). The enhanced electrochemical performance of TSAC nanosheets is mainly a result of their fast Li-ion transport, large surface area and small charge transfer resistance. The discovery in this work highlights the uniqueness of a family of 2D layered MAX materials, such as Ti₃GeC₂, Ti₃SnC₂ and Ti₂SC, which will likely be the promising choices as anode materials for lithium-ion batteries (LIBs).