Electrostatic Self-assembly of 0D–2D SnO₂ Quantum Dots/Ti₃C₂T_x MXene Hybrids as Anode for Lithium-Ion Batteries

MXenes, a new family of two-dimensional (2D) materials with excellent electronic conductivity and hydrophilicity, have shown distinctive advantages as a highly conductive matrix material for lithium-ion battery anodes. Herein, a facile electrostatic self-assembly of SnO₂ quantum dots (QDs) on Ti₃C₂T_x MXene sheets is proposed. The as-prepared SnO₂/MXene hybrids have a unique 0D–2D structure, in which the 0D SnO₂ QDs (~ 4.7 nm) are uniformly distributed over 2D Ti₃C₂T_x MXene sheets with controllable loading amount. The SnO₂ QDs serve as a high capacity provider and the “spacer” to prevent the MXene sheets from restacking; the highly conductive Ti₃C₂T_x MXene can not only provide efficient pathways for fast transport of electrons and Li ions, but also buffer the volume change of SnO₂ during lithiation/delithiation by confining SnO₂ QDs between the MXene nanosheets. Therefore, the 0D–2D SnO₂ QDs/MXene hybrids deliver superior lithium storage properties with high capacity (887.4 mAh g⁻¹ at 50 mA g⁻¹), stable cycle performance (659.8 mAh g⁻¹ at 100 mA g⁻¹ after 100 cycles with a capacity retention of 91%) and excellent rate performance (364 mAh g⁻¹ at 3 A g⁻¹), making it a promising anode material for lithium-ion batteries.[Figure not available: see fulltext.]