Nitrogen-Doped Carbon-Coated SnO₂/Sn Nanocomposites by Supercritical Hydrothermal Synthesis as Advanced Anodes for Lithium-Ion Batteries

The SnO₂anode has a significant volume expansion and low conductivity for lithium-ion batteries (LIBs), which seriously hinder its commercial application in LIBs. Therefore, it is necessary to innovate the design and preparation methods and synthesize high-performance SnO₂-based nanocomposite anode materials. For this purpose, we report the preparation of SnO₂/Sn and nitrogen-doped carbon (SnO₂/Sn@N-C) composite materials for LIB electrodes via supercritical hydrothermal synthesis and the hydrothermal method. The composite anode material was characterized by transmission electron microscopy, and ultrafine SnO₂and Sn nanoparticles were found to be uniformly distributed on the carbon matrix. Compared with original SnO₂, the addition of nitrogen-doped carbon improved the overall performance of the electrode. Therefore, the synthesized SnO₂/Sn@N-C composite materials have good cycling performance, and the reversible capacity was 523.7 mAh g^–1after 50 cycles at 0.1C and 416.8 mAh g^–1after 400 cycles at 1C.