Amorphous Oxyhalide Matters for Achieving Lithium Superionic Conduction

• Published in: Journal of the American Chemical Society 2024-02, Vol.146 (5), p.2977-2985
• Main Authors: Zhang, Shumin, Zhao, Feipeng, Chang, Lo-Yueh, Chuang, Yu-Chun, Zhang, Zhen, Zhu, Yuanmin, Hao, Xiaoge, Fu, Jiamin, Chen, Jiatang, Luo, Jing, Li, Minsi, Gao, Yingjie, Huang, Yining, Sham, Tsun-Kong, Gu, M. Danny, Zhang, Yuanpeng, King, Graham, Sun, Xueliang
• Format: Article
• Language: English
• Subjects: Halogens; Heat transfer; Inorganic compounds; Ionic conductivity; Thermodynamic modeling
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.3c07343

The recently surged halide-based solid electrolytes (SEs) are great candidates for high-performance all-solid-state batteries (ASSBs), due to their decent ionic conductivity, wide electrochemical stability window, and good compatibility with high-voltage oxide cathodes. In contrast to the crystalline phases in halide SEs, amorphous components are rarely understood but play an important role in Li-ion conduction. Here, we reveal that the presence of amorphous component is common in halide-based SEs that are prepared via mechanochemical method. The fast Li-ion migration is found to be associated with the local chemistry of the amorphous proportion. Taking Zr-based halide SEs as an example, the amorphization process can be regulated by incorporating O, resulting in the formation of corner-sharing Zr–O/Cl polyhedrons. This structural configuration has been confirmed through X-ray absorption spectroscopy, pair distribution function analyses, and Reverse Monte Carlo modeling. The unique structure significantly reduces the energy barriers for Li-ion transport. As a result, an enhanced ionic conductivity of (1.35 ± 0.07) × 10–3 S cm–1 at 25 °C can be achieved for amorphous Li3ZrCl4O1.5. In addition to the improved ionic conductivity, amorphization of Zr-based halide SEs via incorporation of O leads to good mechanical deformability and promising electrochemical performance. These findings provide deep insights into the rational design of desirable halide SEs for high-performance ASSBs.