Rhombohedral NaZr₂(PO₄)₃ is the prototype of all the NASICON‐type materials. The ionic diffusion in these rhombohedral NASICON materials is highly influenced by the ionic migration channels and the bottlenecks in the channels which have been extensively studied. However, no consensus is reached as to which one is the preferential ionic migration channel. Moreover, the relationships between the Na⁺ distribution over the multiple available sites, concerted migration, and diffusion properties remain elusive. Using ab initio molecular dynamics simulations, here it is shown that the Na⁺ ions tend to migrate through the Na1–Na3–Na2–Na3–Na1 channels rather than through the Na2–Na3–Na3–Na2 channels. There are two types of concerted migration mechanisms: two Na⁺ ions located at the adjacent Na1 and Na2 sites can migrate either in the same direction or at an angle. Both mechanisms exhibit relatively low migration barriers owing to the potential energy conversion during the Na⁺ ions migration process. Redistribution of Na⁺ ions from the most stable Na1 sites to Na2 on increasing Na⁺ total content further facilitates the concerted migration and promotes the Na⁺ ion mobility. The work establishes a connection between the Na⁺ concentration in rhombohedral NASICON materials and their diffusion properties.

中文翻译：

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菱面体NASICON中Na +分布，协同迁移与扩散特性之间的关系

菱形NaZr ₂（PO ₄）₃是所有NASICON型材料的原型。这些菱形NASICON材料中的离子扩散受到已广泛研究的离子迁移通道和通道瓶颈的高度影响。然而，关于哪个是优先离子迁移通道，尚未达成共识。此外，Na ⁺在多个可用位点上的分布，协同迁移和扩散特性之间的关系仍然难以捉摸。使用从头算分子动力学模拟，可以看出Na ⁺离子倾向于通过Na1-Na3-Na2-Na3-Na1通道迁移，而不是通过Na2-Na3-Na3-Na2通道迁移。有两种类型的协调迁移机制：位于相邻Na1和Na2位置的两个Na ⁺离子可以沿相同方向或成一定角度迁移。由于Na ⁺离子迁移过程中的潜在能量转换，这两种机制均显示出相对较低的迁移势垒。随着Na ⁺总含量的增加，Na ⁺离子从最稳定的Na1位点到Na2的重新分布进一步促进了协调的迁移并促进了Na ⁺离子迁移。这项工作建立了Na ⁺之间的联系 菱面体NASICON材料中的浓度及其扩散特性。