Sodiophilic Na3Sb Framework-Regulated Sodium Deposition and Interphase Evolution for Dendrite-Free and Long-Life Sodium Metal Batteries.

Sodium (Na) metal anodes are attracting great attention as next-generation energy storage systems due to their high theoretical capacity, abundant resources, and low cost. However, an unstable solid-electrolyte interphase (SEI), uncontrolled dendrite growth, and large volume changes are major factors limiting the practical application of Na metal anodes. Herein, we develop a Na-Sb alloy anode featuring a three-dimensional sodiophilic Na3Sb framework embedded within a metallic Na matrix. The interconnected Na3Sb framework homogenizes the Na+ flux and provides abundant Na nucleation sites, enabling uniform Na deposition while effectively suppressing dendrite growth. Moreover, the engineered interface promotes the formation of a dense, NaF-rich inorganic SEI with high mechanical strength and chemical stability, which effectively accommodates volume changes and stabilizes the Na metal/electrolyte interface during repeated cycling. Consequently, the NSF-3||NSF-3 symmetric cell delivers remarkably stable cycling for over 1000 h at 0.5 mA cm-2 with a capacity of 0.5 mAh cm-2, exhibiting significantly improved interfacial stability and Na plating behavior. This work demonstrates that constructing a sodiophilic Na3Sb framework is an effective strategy for regulating Na deposition and stabilizing the Na metal interface, providing a practical pathway toward high-energy-density and long-life sodium metal batteries.