Dealloying Engineering and Interfacial Catalyzing toward Long-Lifespan Anode-Free Sodium Metal Battery

Anode-free Na metal batteries are acclaimed for their high energy densities achieved through current collectors in situ plated with Na metal in the absence of active negative materials. However, realizing high reversible Na plating/stripping on a bare current collector and stable electrolyte chemistry is challenging. Herein, we report a dealloying strategy to treat a Chinese paktong current collector, controlling its crystal orientation and surface properties in situ. The dealloyed foil (D-CNZ) with (220) orientation and high Ni content provides high-affinity nucleation sites that initiate and sustain a uniform Na metal deposition, and catalytic active sites to form a propitious solid electrolyte interphase layer. Dealloying treatment enables a highly reversible Na plating/stripping for 10 000 h (1 mA cm^-2/1 mAh cm^-2), significantly outperforming current collectors reported in the literature. The present anode-free Na metal battery (AFSMB) prototype, comprised of D-CNZ current collector, Na₃V₂(PO₄)₃ cathode, and ether electrolyte can operate for over 200 cycles at 1C, and 100 cycles at 10C. In addition, the NVP||D-CNZ anode-free pouch cell delivers 102 mAh g^-1 at 0.5C and maintains 97% capacity over 120 cycles. Our superior AFSMB enabled by the D-CNZ enlightens an arena toward large-scale energy storage applications.