MoS_2 intercalated P-Ti_3C_2 anode materials with sandwich-like three dimensional conductive networks for lithium-ion batteries

摘要

As a promising anode material, Ti_3C_2 has got increasing attention in recent years for its brilliant per?formance in conductivity and hydrophilicity. However, the application of Ti_3C_2 is limited by its low ca?pacity. Herein, a sandwich-like three dimensional conductive network of M0S2 intercalated p-Ti_3C_2 (partially oxidized Ti_3C_2) is fabricated by selective etching and subsequent hydrothermal treatment to overcome the shortcomings of Ti_3C_2. During the hydrothermal treatment, some TiO_2 nanocrystals are formed by partial oxidation of Ti_3C_2. The ultra high structural stability of TiO_2 nanocrystals upon lithium ion insertion and extraction process is beneficial to maintaining the cyclic stability of MoS_2 modified p-Ti_3C_2 composites. In this architecture, MoS2 acts as an intercalation agent to prevent the p-Ti_3C_2 layers from restacking and facilitate the rapid transportation of electrons and ions between layers. The expanded interlayer space of p-Ti_3C_2provides extra free space to alleviate the volume change of MoS_2. The optimal content of M0S2 is 20% in this study. The synergistic effect of p-Ti_3C_2 and 20 wt% MoS_2 endows composite with maximum discharge capacity of 656 mAh g~(-1) at 50 mA g~(-1), which is signifi?cantly higher than the theoretical capacity of Ti_3C_2 (320 mAh g~(-1)). The sample also shows excellent cycling stability at 500 mAh g~(-1). Even at high current density of 3000 mAh g~(-1) a stable specific capacity of 153 mAh g~(-1) is obtained. These results clearly indicate that intercalation with MoS_2 is an effective strategy to improve the electrochemical performance of Ti_3C_2.