UCl<sub>3</sub>-Type Crystalline Oxychloride Electrolytes for All-Solid-State Lithium-Ion Batteries
Junlong Yang, Shiwei Chen, Qiong Yuan, Guangsu Tan, Qinzhe Liu, Shaoyu Yang, Yanxin Deng, Yingbo Zhao, Wei Liu, Yi Yu, Yanming Cui, Jian Wang, Shou‐Hang Bo, Chao Xu
Abstract
Halide solid-state electrolytes are promising for next-generation all-solid-state lithium-ion batteries due to their high ionic conductivity and wide electrochemical windows. While most research focuses on close-packed crystal structures, nonclose-packed frameworks─exemplified by UCl 3 -type structures─offer unique advantages in enhancing lithium-ion transport via reduced diffusion barriers. Here, we report a new family of UCl 3 -type crystalline oxychloride electrolytes, Li 0.388+ x La 0.475 Ta 0.238 Cl 3– x O x (0 ≤ x ≤ 0.388, LLTCO), synthesized via rapid high-energy shake milling. The material with an optimized composition ( x = 0.15) exhibits high ionic conductivity above 2 mS cm –1 at 30 °C, oxidative stability exceeding 5 V vs Li/Li +, and excellent mechanical compressibility. Moreover, the LLTCO-based Li–Li symmetric cells show a long cycle life, indicating their strong capacity to suppress lithium dendrite formation. Spectroscopy analyses reveal the successful incorporation of oxygen, which preferentially substitutes Cl – around Ta 5+ sites without compromising crystallinity, even at a high oxygen content. The oxygen incorporation further promotes the formation of Li environments with fast dynamics, accounting for the enhanced conductivity. All-solid-state batteries utilizing the optimized oxychloride electrolyte in conjunction with Ni-rich cathodes demonstrate enhanced reversible capacities compared to their undoped counterparts. This work highlights the benefits of nonclose-packed UCl 3 -type oxychloride electrolytes, offering new design strategies for high-performance all-solid-state batteries.