Recent progress in multilayer solid electrolytes for sodium-ion batteries

The development and application of electrochemical energy storage has become increasingly important in the face of the world's excess carbon emissions today. Lithium-ion batteries (LIBs), which have been fully commercialized, are facing the dilemma of insufficient lithium resources, while sodium-ion batteries (SIBs), which are chemically similar, more abundant, and less costly, have become an important alternative to LIBs. Specifically, solid-state sodium-ion batteries (SSSIBs) with high safety are more suitable for large-scale energy storage systems. However, the further application of solid electrolytes is hindered by their poor mechanical properties, high interface resistances and sodium dendrites. To solve these problems, multilayer electrolyte structures have been utilized to improve the interfacial issues. This paper reviews the growth mechanism of sodium dendrites, as well as the current research progress and contents of multilayer electrolytes in SIBs. Finally we look forward to the application prospects and urgent challenges of multilayer structured electrolytes. It is expected that this review will guide the development of multilayer electrolytes for high-performance solid-state batteries.