Kinetically Stabilized Cation Arrangement in Li3YCl6 Superionic Conductor during Solid‐State Reaction. Issue 15 (17th June 2021)

• Record Type: Journal Article
• Authors: Ito, Hiroaki; Shitara, Kazuki; Wang, Yongming; Fujii, Kotaro; Yashima, Masatomo; Goto, Yosuke; Moriyoshi, Chikako; Rosero‐Navarro, Nataly Carolina; Miura, Akira; Tadanaga, Kiyoharu
• Is Part Of: Advanced science. Volume 8:Issue 15(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-06-17
• Subjects: density functional theory -- halides -- in situ XRD -- neutron diffraction -- solid electrolytes; Science -- Periodicals; 505
• DOI: 10.1002/advs.202101413
• Languages: English
• ISSNs: 2198-3844

Abstract

Abstract: The main approach for exploring metastable materials is via trial‐and‐error synthesis, and there is limited understanding of how metastable materials are kinetically stabilized. In this study, a metastable phase superionic conductor, β ‐Li3 YCl6, is discovered through in situ X‐ray diffraction after heating a mixture of LiCl and YCl3 powders. While Cl − arrangement is represented as a hexagonal close packed structure in both metastable β ‐Li3 YCl6 synthesized below 600 K and stable α ‐Li3 YCl6 above 600 K, the arrangement of Li + and Y 3+ in β ‐Li3 YCl6 determined by neutron diffraction brought about the cell with a 1/√3 a ‐axis and a similar c ‐axis of stable α ‐Li3 YCl6 . Higher Li + ion conductivity and lower activation energy for Li + transport are observed in comparison with α ‐Li3 YCl6 . The computationally calculated low migration barrier of Li + supports the low activation energy for Li + conduction, and the calculated high migration barrier of Y 3+ kinetically stabilizes this metastable phase by impeding phase transformation to α ‐Li3 YCl6 . This work shows that the combination of in situ observation of solid‐state reactions and computation of the migration energy can facilitate the comprehension of the solid‐state reactions allowing kinetic stabilization of metastable materials, and can enable the discovery of new metastable materials in a short time. Abstract : A metastable superionic conductor, β ‐Li3 YCl6, is synthesized by heating a mixture of LiCl and YCl3 powders. The computationally calculated low migration barrier of Li + supports the low activation energy for Li + conduction, and the calculated high migration barrier of Y 3+ kinetically stabilizes this metastable phase by impeding phase transformation to thermodynamically stable α ‐Li3 YCl6 .