Recent advanced development of stabilizing sodium metal anodes

As the application of next-generation energy storage systems continues to expand, rechargeable secondary batteries with enhanced energy density and safety are imperative for energy iteration. Sodium-ion batteries (SIBs) have attracted extensive attention and are recognized as ideal candidates for large-scale energy storage due to the abundant sodium resources and low cost. Sodium metal anodes (SMAs) have been considered as one of the most attractive anode materials for SIBs owing to their high specific capacity (1166 mAh g−1), low redox potential, and abundant natural resources. However, the uncontrollable dendrite growth and inevitable side reactions on SMA lead to the continuous deterioration of the electrochemical performance, causing serious safety concerns and limiting their practical application in the future. Therefore, the construction of stable dendrite-free SMAs is a pressing problem for advanced sodium metal batteries (SMBs). In this review, we comprehensively summarize the research progress in suppressing the formation of sodium dendrite, including artificial solid electrolyte interphase (SEI), liquid electrolyte modification, three-dimensional (3D) host materials, and solid-state electrolyte. Additionally, key aspects and prospects of future research directions for SMAs are highlighted. We hope that this timely review can provide an overall picture of sodium protection strategies and stimulate more research in the future.