Silicon-based anode materials are attracting considerable attention due to their high specific capacity for further improving the energy density of lithium-ion batteries (LIBs). Among them, silicon monoxide (SiO) has a good balance between high specific capacity and cycling lifespan, which is increasingly valuable in the market of lithium-ion batteries. However, its poor initial coulombic efficiency (ICE) severely impedes the commercialization of SiO. Although prelithiation and surface carbon coating are considered effective methods to reduce irreversible consumption during the initial lithiation process, the synergistic relationship between prelithiation and carbon coating has not yet been confirmed. Herein, we used LiH as solid-phase prelithiation reagent and acetylene as carbon source for carbon coating to improve the ICE as well as cyclic stability of SiO anode. Results show that the process sequence of pre-lithiation and carbon coating has a significant impact on regulating the internal lithium silicate components and the microcrystalline size of silicon and lithium silicates. A prioritizing carbon layer coating subsequent to prelithiation can achieve physical barrier effect, effectively regulating the prelithiation reaction process to refine the internal silicon and lithium silicate crystal material, and avoiding the formation of lithium-poor LiSiO phase. The obtained SOC-P sample exhibits a superior ICE of 88.1 % and a stable irreversible capacity of 842.9 mAh/g after 200 cycles. This work provides practical reference idea for solving the low initial efficiency issue of SiO anode material.

中文翻译：

---

通过碳层调控的成分控制和微晶尺寸限制来提高 SiO2 阳极的初始库伦效率


硅基负极材料由于其高比容量而受到广泛关注，可进一步提高锂离子电池（LIB）的能量密度。其中，一氧化硅（SiO）在高比容量和循环寿命之间具有良好的平衡，在锂离子电池市场中越来越有价值。然而，其较差的初始库仑效率（ICE）严重阻碍了SiO的商业化。尽管预锂化和表面碳涂层被认为是减少初始锂化过程中不可逆消耗的有效方法，但预锂化和碳涂层之间的协同关系尚未得到证实。在此，我们使用LiH作为固相预锂化试剂，并使用乙炔作为碳涂层的碳源，以提高SiO阳极的ICE和循环稳定性。结果表明，预锂化和碳包覆的工艺顺序对调节硅酸锂内部组分以及硅和硅酸锂的微晶尺寸具有显着影响。预锂化后优先涂覆碳层可以达到物理屏障效果，有效调控预锂化反应过程，细化内部硅和硅酸锂晶体材料，避免形成贫锂LiSiO相。所获得的 SOC-P 样品在 200 次循环后表现出 88.1% 的优异 ICE 和 842.9 mAh/g 的稳定不可逆容量。该工作为解决SiO负极材料初始效率低的问题提供了实用的参考思路。