Crystal Structural Framework of Lithium Super‐Ionic Conductors

• Published in: Advanced energy materials Vol. 9; no. 43
• Main Authors: He, Xingfeng, Bai, Qiang, Liu, Yunsheng, Nolan, Adelaide M., Ling, Chen, Mo, Yifei
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-11-2019
• Subjects: ab initio molecular dynamics simulations; computational materials discovery; Computer simulation; Conduction; Conductors; Crystal structure; Dynamic structural analysis; high‐throughput computation; Ion currents; Ions; Lithium; Li‐ion conductors; Molecular dynamics; Room temperature; super‐ionic conductors
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.201902078

As technologically important materials for solid‐state batteries, Li super‐ionic conductors are a class of materials exhibiting exceptionally high ionic conductivity at room temperature. These materials have unique crystal structural frameworks hosting a highly conductive Li sublattice. However, it is not understood why certain crystal structures of the super‐ionic conductors lead to high conductivity in the Li sublattice. In this study, using topological analysis and ab initio molecular dynamics simulations, the crystal structures of all Li‐conducting oxides and sulfides are studied systematically and the key features pertaining to fast‐ion conduction are quantified. In particular, a unique feature of enlarged Li sites caused by large local spaces in the crystal structural framework is identified, promoting fast conduction in the Li‐ion sublattice. Based on these quantified features, the high‐throughput screening identifies many new structures as fast Li‐ion conductors, which are further confirmed by ab initio molecular dynamics simulations. This study provides new insights and a systematic quantitative understanding of the crystal structural frameworks of fast ion‐conductor materials and motivates future experimental and computational studies on new fast‐ion conductors.
Design and discovery of fast‐ion conductor materials are widely pursued to enable novel energy storage and conversion technologies. This computation study systematically analyzes the crystal structures of all lithium‐containing oxides and sulfides and quantifies the key features pertaining to fast‐ion conduction. Based on these quantified features, a high‐throughput screening is performed for discovering new structures for fast Li‐ion conductors.