In-situ construction of g-C₃N₄/Mo₂CT_x hybrid for superior lithium storage with significantly improved Coulombic efficiency and cycling stability

Mo₂CT_x MXene, obtained by etching Ga from the Mo₂Ga₂C, is theoretically predicted to possess high electrochemical activity. However, the preparation of Mo₂CT_x remains challenging due to the difficultly of traditional HF etching. Increasing the exfoliation degree and constructing the protection layer of Mo₂CT_x not only can offer rich active sites but also suppress side reaction, which has been considered as efficient approaches to improving its electrochemical performance. In this work, a facile in-situ strategy was developed to synthesize the graphitic carbon nitride/Mo₂CT_x (g-C₃N₄/Mo₂CT_x) hybrid, smartly employing the conversion from urea to g-C₃N₄ to realize the exfoliation degree of Mo₂CT_x MXene and simultaneously build a protection layer. As expected, the abundant exposed MXene layers are believed to provide rapid diffusion pathways for the ions transport as well as rich active sites for lithium storage. As a result, the target g-C₃N₄/Mo₂CT_x hybrid exhibits a much higher Coulombic efficiency (70.8%) and superior lithium storage performance (525.8 mAh g⁻¹) compared with pure Mo₂CT_x (19.2% and 101.4 mAh g⁻¹). Generally, this synthesis strategy presented in this study paves a new way for the fabrication of MXene based hybrid with high performance for lithium storage.