Constructing novel Si@Sn-SnO2@C dual core-shell composite with synchronous-buffering effect for high reversible capacity and stable lithium-ion battery

Silicon-based composite materials hold great promise as potential anode alternatives for the next generation of lithium-ion batteries (LIBs) due to their low cost and high theoretical capacity. However, their practical application is hindered by the sluggish diffusion kinetics of lithium ions and significant volume expansion effects, which severely limit their actual capacity and cycle performance. This study describes the development of a novel Si@Sn-SnO2@carbon composite, which exhibits a synchronous buffering effect, thereby enabling high reversible capacity and stable LIBs. In this composite structure, a consistent 5-10 nm thick Sn-SnO2 layer is coated onto the nano-Si surface, and a uniform 7-10 nm thick amorphous carbon layer is applied to the outermost layer, creating a double-layer core-shell architecture. The innovative composite electrode offers several advantages: it adapts well to stress and maintains structural integrity, thereby preventing agglomeration and polarization during cycling. Additionally, it facilitates rapid lithium-ion diffusion and efficient electronic transfer, which contribute to high rate capabilities and ultra-stable cycle performance. The study also demonstrates the performance of a full battery incorporating this material, showcasing acceptable electrochemical characteristics. The research findings indicate that the Si@Sn-SnO2@C nanocomposite material developed in this study holds substantial potential for the practical application of high specific energy LIBs.