Ultrafine SnO2 Nanocrystals Self-Anchored in Carbon for Stable Lithium Storage

Sn-based materials can be potentially used as anode in lithium-ion batteries (LIBs), though challenges still exist. Herein, SnO2/C composites with ultrafine SnO2 nanocrystals uniformly anchored to the carbon matrix are simply synthesized via a one-pot solvothermal method. In this structure, the nano-sized SnO2 can offer abundant electroactive sites and effectively shorten the lithium-ion diffusion length. The interfacial structure between SnO2 and the carbon matrix restricts the particle within a specific space, allowing elastic buffering and alleviating the agglomeration and pulverization. Therefore, the capacity decay due to volume variation upon cycling can be refrained remarkably. Moreover, the unique interfaces facilitate electron transfer, as well as additional lithium storage (i.e., pseudocapacitance). Benefiting from these unique architectural merits, our optimized SnO2/C composite exhibits high specific capacity (600 mAhg(-1) at 0.2 Ag-1) and superior rate capability (185 mAhg(-1) at 11.7 Ag-1) when applied to LIBs anodes. Even without an additional conductive agent, the electrode can maintain its extremely stable performance. The strategy proposed here proves the feasibility to enhance electrochemical properties, utilizing the synergetic effect between SnO2 nano-crystals and the carbon base. Thus, the optimized SnO2/C is a promising candidate for applications as anode material in LIBs.