A preparation strategy for highly reversible conversion reaction Tin dioxide/ Carbon anode: Simple, ultrafast and scalable

Combining nanoscale engineering and physical confinement approach to prevent aggregation is a reliable strategy to achieve fully reversible conversion reaction SnO2-based anode. However, the synthesis of such nanostructures relies on complex self-sacrificing template preparation and time-consuming thermal treatment processes, which limit the practical application of high-performance SnO2 anodes for lithium-ion batteries. Herein, we present a simple strategy for the in situ preparation of SnO2 quantum dots embedded in carbon martix using an inherently advantageous MOF template and ultrafast microwave-assisted treatment in a few seconds. (denoted as SnO2 QDs@C). The dispersed SnO2 quantum dots with precise size control (≈5 nm) in the nanostructure shorten the lithium ion transport distance and enhance the reaction kinetics. Meanwhile, the carbon matrix promotes electron transport and suppresses Sn coarsening, thus achieving a highly reversible conversion reaction. Consequently, the SnO2 QDs@C anode achieves a reversible capacity of 1337 mAh g-1 after 200 cycles at 0.2 A g-1 with a capacity retention rate of more than 80%. This preparation method can be extended to prepare other metal oxide quantum dots/ Carbon composites and is expected to be applied in a wide range of fields.