Halide and oxyhalide solid-state electrolytes: From structural chemistry to electrochemical applications in all-solid-state Na-ion batteries

초록

All-solid-state sodium-ion batteries are attracting attention as safe and cost-effective energy storage systems. Their development hinges on solid-state electrolytes that provide sufficient ionic conductivity, wide electrochemical stability, and compatibility with electrodes. Recently, halide and oxyhalide SSEs have emerged as promising alternatives to sulfide and oxide counterparts, offering a balance of conductivity, structural flexibility, and high-voltage stability. This review highlights advances in sodium halide and oxyhalide electrolytes, focusing on their structural chemistry, ion-transport mechanisms, and electrochemical performance. Halide systems across groups 3, 4, 5, and 13 benefit from strategies such as vacancy engineering, cation substitution, and anion mixing, whereas oxyhalides expand Na+ pathways and enhance interfacial stability through oxygen incorporation and amorphization. Electrochemical demonstrations confirm compatibility with polyanionic and layered-oxide cathodes, enabling stable high-voltage cycling and long-term durability. © 2026 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

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