ABSTRACT The transport properties of the solid electrolyte interphase (SEI) play an important role in the charging and discharging process of lithium-ion batteries (LIBs). We used nonequilibrium molecular dynamics (NEMD) simulation to mimic the lithium permeability of SEI films with different chemical compositions, thicknesses and densities. We found the order of permeability to be Li2CO3 > LiF > compound > Li2O > LiOH. Permeability is likely more affected by the binding energy between the lithium ions and the SEI atoms than by structural qualities such as surface area and porosity. The density profiles indicate lithium ions tend to accumulate on the SEI–vacuum interface when the film is less permeable. The transport process does not satisfy Einstein’s diffusion equation, thereby revealing the nonequilibrium nature. The relationship between the chemical compositions, densities, thicknesses and permeabilities of each film is expressed by an empirical equation, which can be used to quickly predict the transport properties of SEI films.

中文翻译：

---

了解 SEI 薄膜中的锂传输：非平衡分子动力学模拟

摘要固体电解质中间相（SEI）的传输特性在锂离子电池（LIBs）的充放电过程中起着重要作用。我们使用非平衡分子动力学 (NEMD) 模拟来模拟具有不同化学成分、厚度和密度的 SEI 薄膜的锂渗透率。我们发现渗透率的顺序为 Li2CO3 > LiF > 化合物 > Li2O > LiOH。与结构特性（如表面积和孔隙率）相比，渗透率可能更受锂离子和 SEI 原子之间结合能的影响。密度分布表明，当薄膜渗透性较低时，锂离子倾向于在 SEI-真空界面上积聚。输运过程不满足爱因斯坦的扩散方程，从而揭示了非平衡性质。