Electrostatic Self-assembly of 0D-2D SnO2 Quantum Dots/Ti3C2Tx 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 Ti3C2Tx MXene sheets is proposed. The as-prepared SnO2/MXene hybrids have a unique 0D-2D structure, in which the 0D SnO2 QDs (similar to 4.7 nm) are uniformly distributed over 2D Ti3C2Tx 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 Ti3C2Tx 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.