Anion sublattice design enables superionic conductivity in crystalline oxyhalides.

Zhao, Feipeng; Zhang, Shumin; Wang, Shuo; Reid, Joel W; Xia, Wei; Liu, Jue; King, Graham; Kaduk, James A et al. · Science · 2025

basic_science · Level V

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Abstract

Solid-state batteries are attractive energy storage systems as a result of their inherent safety, but their development hinges on advanced solid-state electrolytes (SSEs). Most SSEs remain largely confined to single-anion systems (e.g., sulfides, oxides, halides, and polymers). Through mixed-anion design strategy, we develop crystalline Li<sub>3</sub>Ta<sub>3</sub>O<sub>4</sub>Cl<sub>10</sub> (LTOC) and its derivatives with excellent ionic conductivities (up to 13.7 millisiemens per centimeter at 25°C) and electrochemical stability. The LTOC structure features mixed-anion spiral chains, consisting of corner-shared oxygen and terminal chlorine atoms, which induces continuous "tetrahedron-tetrahedron" Li-ion migration pathways with low energy barriers. Additionally, LTOC demonstrates holistic cathode compatibility, enabling solid-state batteries operation at 4.9 volts versus Li/Li<sup>+</sup> and low temperature, down to -50°C. These findings describe a promising class of superionic conductors for high-performance solid-state batteries.