Low-cost and high-efficiency production of silicon-based material is the key to improve the energy density of lithium-ion batteries. Herein, we propose a novel structure of FeSi₂–Si eutectic nanoparticles protected by the SiO_x shell. FeSi₂, as a buffer phase can improve the electrochemical stability of the electrode. A SiO_x shell is formed on the surface of the nanoparticles through the passivation process. SiO_x encapsulated FeSi₂–Si eutectic nanoparticles exhibit excellent capacity of 674.9 mAh/g after 500 charge/discharge cycles. The capacity retention rate is above 90% after the stabilization process. This work provides a new nanomaterial design for high performance silicon-based anode materials of lithium-ion batteries.

低成本、高效率地生产硅基材料是提高锂离子电池能量密度的关键。在此，我们提出了一种由 SiO _x壳保护的 FeSi ₂ -Si 共晶纳米颗粒的新型结构。FeSi ₂作为缓冲相可以提高电极的电化学稳定性。通过钝化过程在纳米粒子表面形成SiO _x壳。SiO _x封装的 FeSi ₂–Si 共晶纳米颗粒在 500 次充电/放电循环后表现出 674.9 mAh/g 的优异容量。稳定化后的容量保持率在90%以上。这项工作为锂离子电池的高性能硅基负极材料提供了一种新的纳米材料设计。