Research progress of inorganic solid electrolyte materials for all‐solid‐state sodium‐ion batteries

Abstract Sodium‐ion batteries have garnered significant attention due to their abundant sodium resources and low cost, showing great potential for large‐scale energy storage. However, traditional sodium‐ion batteries, which rely on flammable liquid electrolytes as the ion transport medium, pose safety challenges in practical applications. Using solid‐state electrolytes instead of liquid electrolytes can effectively improve the safety and electrochemical performance of battery systems, making solid‐state sodium‐ion batteries as a highly promising option for energy storage. Solid‐state electrolytes are categorized into organic and inorganic types. Inorganic solid‐state electrolytes have garnered increased interest for their high ionic conductivity, high ion mobility, excellent mechanical properties, and good thermal stability. This review systematically explores the advancements in various inorganic solid‐state electrolytes, including β‐Al 2 O 3 , sodium superionic conductor, sulfide, halide, complex hydride, and anti‐perovskite. The review focuses on material preparation, ionic conductivity, and electrochemical properties. Additionally, it addresses the interface challenges between inorganic solid‐state electrolytes and electrode materials, along with effective strategies to improve these interfaces.