Progress on Designing Artificial Solid Electrolyte Interphases for Dendrite-Free Sodium Metal Anodes

Nature-abundant sodium metal is regarded as ideal anode material for advanced batteries due to its high specific capacity of 1166 mAh g−1 and low redox potential of −2.71 V. However, the uncontrollable dendritic Na formation and low coulombic efficiency remain major obstacles to its application. Notably, the unstable and inhomogeneous solid electrolyte interphase (SEI) is recognized to be the root cause. As the SEI layer plays a critical role in regulating uniform Na deposition and improving cycling stability, SEI modification, especially artificial SEI modification, has been extensively investigated recently. In this regard, we discuss the advances in artificial interface engineering from the aspects of inorganic, organic and hybrid inorganic/organic protective layers. We also highlight key prospects for further investigations.