Configurational and Dynamical Heterogeneity in Superionic Li 5.3 PS 4.3 Cl 1.7− x Br x
Configurational and Dynamical Heterogeneity in Superionic Li 5.3 PS 4.3 Cl 1.7− x Br x
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超离子 Li 5.3 PS 4.3 Cl 1.7â x Br x 的构型和动力学异质性
DOI：
10.1002/adfm.202307954
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发表时间：
2023
影响因子：
19
通讯作者：
Hu, Yan‐Yan
中科院分区：
文献类型：
--
作者：
Wang, Pengbo;Patel, Sawankumar;Liu, Haoyu;Chien, Po‐Hsiu;Feng, Xuyong;Gao, Lina;Chen, Benjamin;Liu, Jue;Hu, Yan‐Yan
由于在表征阴离子无序方面的挑战，高熵Li+导体中的晶格化学和阳离子迁移之间的关联还没有完全被理解。为了解决这个问题，研究了使阴离子晶格结构工程成为可能的锂离子导体银辉石族。具体地说，合成了具有不同阴离子熵的新银辉石Li5.3PS4.3Cl1.7−xBrx(0≤x≤1.7)，并用X射线衍射、中子散射和多核高分辨固体核磁共振对其结构进行了确定。离子和晶格动力学采用变温多核核磁共振弛豫测量和中子散射的最大熵分析，辅以约束从头算分子动力学计算。确定了15种阴离子排列的原子组态，产生了广泛的局域晶格动力学。晶格结构、组成和动力学中的高熵稳定了其他亚稳的缺锂结构，并使阳离子迁移的能量格局变得平坦。这导致了最高的室温离子电导率为26ms cm−1，在Li5.3PS4.3Cl0.7Br中实现了低激活能0.155 eV，其中阴离子无序度最大。这项研究揭示了高熵快离子导体的复杂结构-性质关系，突出了异质性在晶格动力学中的重要意义。
The correlation between lattice chemistry and cation migration in high‐entropy Li+conductors is not fully understood due to challenges in characterizing anion disorder. To address this issue, argyrodite family of Li+conductors, which enables structural engineering of the anion lattice, is investigated. Specifically, new argyrodites, Li5.3PS4.3Cl1.7−xBrx(0 ≤x≤ 1.7), with varying anion entropy are synthesized and X‐ray diffraction, neutron scattering, and multinuclear high‐resolution solid‐state nuclear magnetic resonance (NMR) are used to determine the resulting structures. Ion and lattice dynamics are determined using variable‐temperature multinuclear NMR relaxometry and maximum entropy method analysis of neutron scattering, aided by constrained ab initio molecular dynamics calculations. 15 atomic configurations of anion arrangements are identified, producing a wide range of local lattice dynamics. High entropy in the lattice structure, composition, and dynamics stabilize otherwise metastable Li‐deficient structures and flatten the energy landscape for cation migration. This resulted in the highest room‐temperature ionic conductivity of 26 mS cm−1and a low activation energy of 0.155 eV realized in Li5.3PS4.3Cl0.7Br, where anion disorder is maximized. This study sheds light on the complex structure–property relationships of high‐entropy superionic conductors, highlighting the significance of heterogeneity in lattice dynamics.