In Situ Construction of Sodiophilic Alloy Interface Enabled Homogenous Na Nucleation and Deposition for Sodium Metal Anode

The sodium (Na) metal anode is a desirable anode for the next-generation batteries because of its abundant resources and the high specific capacity. However, the poor cyclic stability hinders its practical application. In this study, we report a facile strategy of in situ constructing sodiophilic alloying sites for Na metal anodes by using zinc (Zn) foil as the current collector, which enables smooth and compact deposition morphology and excellent cyclic stability. The Zn current collector and the initial deposited Na generate a NaZn₁₃ alloy interface, which can guide the subsequent plating/stripping behavior of Na. As a result, the Na metal anode with Zn current collector exhibits ultrahigh stability with Coulombic efficiency of 99.87% (over 450 cycles at 1 mA cm⁻² for 1 mAh cm⁻²). Furthermore, the impressive capacity retention (98.5% after 40 cycles at 0.5 C) in Zn∣∣NVP (Na₃V₂(PO₄)₃) batteries suggests the anticipated application prospect of Zn current collector in anode-free Na metal batteries, which opens up a new way for the evolution of the next generation of safe and efficient Na metal anodes.