Lithiation:\nA Pathway to Strengthen Sodiophilic Metal\nInterlayer of 3D Metallic Skeleton for High-Performance Sodium Metal\nAnodes

Constructing a three-dimensional (3D) skeleton with a\nsodiophilic-modified\nlayer (SML) has been proven to be an effective strategy to alleviate\nexcessive volumetric deformation and continuous dendrite growth for\nsodium (Na) metal anodes. However, the weak binding force and violent\nreaction between the SML and the 3D skeleton lead to numerous cracks/defects\nand even pulverization of the SML during repeated Na plating/stripping.\nHerein, a lithiation pathway is presented to construct a sodiophilic\nLi–Sn alloy layer onto a 3D copper mesh to strengthen the SML\nfor stable Na metal anodes. The lithiation 3D skeleton exhibits superior\nsodiophilicity, higher charge-transfer efficiency, and lower ion-diffusion\nbarrier, contributing to the homogenization of ion-electronic flux\nand Na deposition. Simultaneously, the dense Li–Sn alloy is\nmore stable than the monometal Sn-layer, which effectively prevents\ndamage to the SML and enhances the stability of the SML. As a result,\nthe asymmetrical cell exhibits great performance with a negligible\nnucleation overpotential and a high average Coulombic efficiency of\n99.4%. Moreover, the full cell assembled with Na<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> cathode delivers superior capacity\nretention of 91.3% after 1000 cycles at a current of 3C.