Manipulation of the Anode Interphase by Multicomponent Composite Sodium for Fast‐Charging and Low‐Temperature Sodium Metal Batteries

Abstract Stable operation in the all‐climate condition is a practical pursuit of the development of high‐performance sodium metal batteries (SMBs), however, blocked by the instable interphases and slow kinetics of metallic anode. Herein, a unique multicomponent Na ₁₅ Sn ₄ /NaF@Na composite anode is specially designed by mechanical rolling method, in which Na ₁₅ Sn ₄ can lower the nucleation barrier and promote the uniform deposition of Na ⁺ , while NaF can prevent electron tunneling and stabilize the interface in the commercially available ester electrolyte, finally enhance performance of the cell. The synergistic manipulated interface by the composite anode can not only facilitate a high stripping/plating capacity and ultralong lifespan without dendrite formation, but also endow the full SMB an ultrafast charging capability and outstanding low‐temperature performance: The Na ₁₅ Sn ₄ /NaF@Na||NVP full cell operates stably for 1175 cycles at an ultrahigh current density of 100 C with 80% capacity retention at room temperature, and maintains stability over 1000 cycles at −20 °C with 97.9% capacity retention. Moreover, the remarkable stability of the full cell at the extreme low temperature of −40 °C or even under the extreme temperature shock, combined with the impressive performance of the pouch cell validly demonstrate the practical application aspect of Na ₁₅ Sn ₄ /NaF@Na composite anode.