Solid-State Electrolytes for Sodium Metal Batteries

The lower energy density and safety issues of liquid sodium-ion batteries have been unable to satisfy the ever-increasing demands for large-scale energy storage system. As a low-cost alternative, solid-state sodium metal batteries (SSMBs) have shown great competitive advantages and extensive application prospects due to their high energy density and desirable safety. However, the solid-state electrolytes (SSEs) often possess low ionic conductivity, and the poor interface compatibility and inferior stability between SSEs and electrodes can result in the continuous deterioration of the electrochemical performance. This review summarizes the recent progresses of sodium-based SSEs, including the sodium ion transport mechanisms of different types of SSEs, some emerging materials in different dimensions, and interface engineering. Furthermore, the critical challenges and new perspectives are emphasized in detail. This review provides deeper insights to construct more comprehensive and effective SSEs for next-generation high-performance SSMBs.