Lithium‐dendrite growth is one of the most challenging problems affecting the safety performance of Li‐ion batteries. Understanding the evolution process of Li‐dendrite growth at the atomic scale is critical for solving this problem. In this paper, the adsorption processes, geometrical configurations, and electronic structures of Li clusters on double‐layered graphene with two types of defects were investigated by first‐principles calculations. It was found that single vacancy (SV) defects tend to promote the nucleation of Li dendrites, and the adsorption energy of Li clusters near the SV defect decreases with increasing number of Li atoms. Meanwhile, the Li atoms accumulated on the surface of SV‐defect graphene with distances between the Li atoms similar to those in bulk metallic Li. However, in the case of double vacancy (DV) defects, the Li atoms could diffuse freely in the direction perpendicular to the graphene sheets through DV defects at the top‐layer graphene, thus hindering nucleation and dendrite growth. Density of states analyses suggested that the Li atoms on SV‐defect graphene transform from the fully ionized state to the metallic state with continuously increasing number, while the ionic properties of the Li atoms remain and even increase on DV‐defect graphene. Our conclusions can help to understand the Li‐graphite interaction from an atomistic point of view and provide theoretical hints for the development of graphite anodes with high charge‐rate properties.

中文翻译：

---

双层缺陷石墨烯上Li成核的第一性原理研究

树枝状锂的生长是影响锂离子电池安全性能的最具挑战性的问题之一。了解原子尺度上锂树枝状晶体生长的演化过程对于解决该问题至关重要。本文通过第一性原理计算研究了具有两种缺陷的双层石墨烯上Li团簇的吸附过程，几何构型和电子结构。发现单空位（SV）缺陷倾向于促进Li树枝状晶体的成核，并且随着Li原子数量的增加，SV缺陷附近的Li团簇的吸附能降低。同时，Li原子聚集在SV缺陷石墨烯的表面，其Li原子之间的距离与大块金属Li中的相似。但是，对于双重空缺（DV）缺陷，Li原子可以通过顶层石墨烯的DV缺陷在垂直于石墨烯片的方向上自由扩散，从而阻碍了形核和枝晶的生长。态密度分析表明，SV缺陷石墨烯上的Li原子随着数量的不断增加从完全电离态转变为金属态，而DV缺陷石墨烯上的Li原子的离子性质保持甚至增加。我们的结论有助于从原子论的角度理解锂-石墨的相互作用，并为开发具有高电荷率特性的石墨阳极提供理论提示。态密度分析表明，SV缺陷石墨烯上的Li原子随着数量的不断增加从完全电离态转变为金属态，而DV缺陷石墨烯上的Li原子的离子性质保持甚至增加。我们的结论有助于从原子论的角度理解锂-石墨的相互作用，并为开发具有高电荷率特性的石墨阳极提供理论提示。态密度分析表明，SV缺陷石墨烯上的Li原子随着数量的不断增加从完全电离态转变为金属态，而DV缺陷石墨烯上的Li原子的离子性质保持甚至增加。我们的结论有助于从原子论的角度理解锂-石墨的相互作用，并为开发具有高电荷率特性的石墨阳极提供理论提示。