All-solid-state Na-ion batteries have emerged as alternatives to all-solid-state Li-ion batteries owing to the global abundance of Na element. However, finding a commercially viable Na-ion solid-state electrolyte (SSE) remains challenging due to the relatively poor understanding of the structures effective for conduction compared to those for Li-ion SSE. In this study, we develop a screening framework based on an unsupervised machine learning technique to characterize Na-ion SSEs according to their lattice structures. Specifically, we evaluate feature vectors encoding 180 structural properties for 12,670 materials containing Na ions. Subsequently, the resulting feature vectors are clustered using hierarchical density-based spatial clustering of applications with noise (HDBSCAN), leading to the discovery of 12 groups including those with experimentally proven Na-ion superionic conductors such as NASICONs and sodium chalcogenides. Post hoc analysis of these clusters reveals that the groups with high conductivity share similar characteristics, including the existence of ion channels for Na ions and the weak interactions between Na ions and the proximate atoms. Ab initio molecular dynamics simulations confirm that the promising groups exhibit exceptional ion diffusivity compared to other groups. By employing decision tree classifiers trained to screen promising groups, we demonstrate the rapid assessment of the potential of a given material. Finally, we offer perspectives and insights for the development of novel Na-ion SSEs for all-solid-state Na-ion batteries.

由于全球丰富的钠元素，全固态钠离子电池已成为全固态锂离子电池的替代品。然而，寻找商业上可行的钠离子固态电解质（SSE）仍然具有挑战性，因为与锂离子固态电解质（SSE）相比，人们对有效传导的结构了解相对较少。在这项研究中，我们开发了一个基于无监督机器学习技术的筛选框架，以根据钠离子 SSE 的晶格结构来表征它们。具体来说，我们评估了编码 12,670 种含有 Na 离子的材料的 180 种结构特性的特征向量。随后，使用基于分层密度的噪声应用空间聚类 (HDBSCAN) 对所得特征向量进行聚类，从而发现了 12 个组，其中包括经过实验证明的钠离子超离子导体，例如 NASICON 和硫族化钠。对这些团簇的事后分析表明，具有高电导率的基团具有相似的特征，包括钠离子离子通道的存在以及钠离子与邻近原子之间的弱相互作用。从头算分子动力学模拟证实，与其他基团相比，有前途的基团表现出出色的离子扩散率。通过使用经过训练的决策树分类器来筛选有前途的群体，我们展示了对给定材料潜力的快速评估。最后，我们为全固态钠离子电池的新型钠离子SSE的开发提供了观点和见解。