Solid‐State Electrolytes for Rechargeable Magnesium‐Ion Batteries: From Structure to Mechanism

Abstract Rechargeable magnesium (Mg)‐ion batteries have received growing attention as a next‐generation battery system owing to their advantages of sufficient reserves, lower cost, better safety, and higher volumetric energy density than lithium‐ion batteries. However, Mg as an anode can be easily passivated during charging/discharging by most common solvents, which are inconducive for magnesium deposition/stripping. Based on this, the development of Mg‐ion solid‐state electrolytes in the last decades led to the formulization of several concepts beyond previously reported designs. These exciting studies have once again sparked an interest in all‐solid‐state magnesium‐ion batteries. In this review, Mg solid‐state electrolytes, including inorganic (oxides, hydrides, and chalcogenides) and organic (metal‐organic frameworks and polymers) materials are classified and summarized in detail. Moreover, the structural characteristics and the migration mechanism of Mg 2+ ions are also discussed with a focus on pending questions and future prospects.