Among various metal phosphides, SnP with a high theoretical specific capacity is a promising anode material. However, the poor cycling stability hinders its application in energy storage. Besides, the lithiation mechanism of SnP has not been well clarified by available studies. To solve the above two issues, experimental investigation and theoretical exploration are performed in this study. The composites of SnP-semifilled carbon nanotubes (CNTs) are proposed and tested as anodes for Li-ion batteries. The specific capacity of SnP@CNTs firstly decays and then experiences an inverse growth. Due to the semifilled structure of SnP@CNTs, the volume expansion of SnP is greatly relieved by the extra space in CNTs. Moreover, owing to the confinement effect of CNTs, the highly pulverized SnP particles are always constrained into CNTs, thus maintaining excellent structural integrity and electrical contact. The pulverization of SnP also contributes to the capacity growth, as a result of increased reaction sites and reduced Li⁺ diffusion distance. Furthermore, SnP is verified to undergo a progressive lithiation process, i.e., Li⁺ is first intercalated in SnP to form amorphous Li_xSnP, followed by transforming into amorphous Li₃P and then Li_4.4Sn. Li⁺ preferentially reacts with P instead of Sn, which is verified through the first-principles calculations.

在各种金属磷化物中，具有较高理论比容量的 SnP 是一种很有前途的负极材料。然而，较差的循环稳定性阻碍了其在储能方面的应用。此外，现有的研究还没有很好地阐明SnP的锂化机制。针对以上两个问题，本研究进行了实验研究和理论探索。提出并测试了 SnP 半填充碳纳米管 (CNT) 的复合材料作为锂离子电池的阳极。SnP@CNTs 的比容量首先衰减然后经历反向增长。由于 SnP@CNTs 的半填充结构，碳纳米管中的额外空间大大缓解了 SnP 的体积膨胀。此外，由于碳纳米管的限制效应，高度粉碎的 SnP 颗粒总是受到限制 碳纳米管，从而保持出色的结构完整性和电接触。由于增加的反应位点和减少的 Li ⁺扩散距离，SnP 的粉化也有助于容量增长。此外，证实SnP经历了渐进式锂化过程，即Li ⁺首先嵌入SnP中以形成非晶Li _x SnP，然后转变为非晶Li ₃ P，然后转变为Li _4.4 Sn。Li ⁺优先与 P 反应而不是与 Sn 反应，这通过第一性原理计算得到验证。