酸素が拓く固体電解質の設計原理～複雑なマルチアニオンガラスにおけるイオン輸送の仕組みを解明～

2025-11-12 東北大学

図1. 酸素含有量による構造変化とナトリウムイオン伝導率の関係
酸素導入量の増加に伴い、架橋酸素（Ta-O-Ta）が形成され、最適組成付近で最高伝導率を示す。

＜関連情報＞

• https://www.tohoku.ac.jp/japanese/2025/11/press20251112-02-Oxygen.html
• https://www.tohoku.ac.jp/japanese/newimg/pressimg/tohokuuniv-press20251112_02web_Oxygen.pdf
• https://pubs.acs.org/doi/10.1021/jacs.5c10564

x Na 2 O-TaCl 5ガラス電解質における酸素媒介構造変調とイオン輸送 Oxygen-Mediated Structural Modulation and Ion Transport in xNa2O-TaCl5 Glass Electrolytes

Zheng Huang,Neha Yadav,Shun Itakura,Peng Song,Hirofumi Akamatsu,Katsuro Hayashi,Prashun Gorai,and Saneyuki Ohno
Journal of the American Chemical Society  Published: November 11, 2025
DOI:https://doi.org/10.1021/jacs.5c10564

Abstract

Understanding the structure–property relationship in glass solid electrolytes (SEs) remains a major challenge due to their inherent disorder and the difficulty of probing local structures, particularly in relation to oxygen incorporation. Despite recent interest in multianion halide solid electrolytes, there are few systematic studies on how varying the oxygen content affects the local structure and ion transport. Here, we investigate a series of amorphous sodium oxychloride SEs with the composition xNa₂O-TaCl₅ (0.1 ≤ x ≤ 1.5), revealing three distinct conductivity regimes and achieving a maximum of 4.1 mS cm^–1 at room temperature. Synchrotron and lab X-ray total scattering and Raman spectroscopy indicate the gradual formation of Ta–O–Ta bonds that bridge the two or more metal chloride polyhedra, while ab initio molecular dynamics simulations clarify the distinct roles of bridging and nonbridging O^2– species. These findings not only provide mechanistic insights into oxygen-mediated glass formation but also establish guiding principles for multianion engineering in the design of next-generation solid electrolytes.