In Situ‐Formed Lithiophilic Li 3 Sb on the Cu Current Collector Enables LiF‐Rich Solid Electrolyte Interphase for Dendrite‐Free and Stable Lithium Metal Anodes

ABSTRACT Lithium metal batteries (LMBs) hold great promise for next‑generation energy storage systems owing to their high theoretical energy density. However, their practical application is hindered by uncontrolled Li dendrite growth and unstable solid electrolyte interphase (SEI). Here, we design a Li 3 Sb‐modified Cu current collector (Li 3 Sb@Cu) that employs a synergistic dual‑function strategy to regulate uniform Li plating and engineer a robust LiF‐rich SEI. The Li 3 Sb interface is constructed in situ by electrochemical lithiation of Cu 2 Sb layer that is directly grown on Cu foil via a galvanic replacement reaction in SbCl 3 solution. Lithiophilic Li 3 Sb interlayer, with high delithiation potential and strong adhesion to the Cu substrate, significantly lowers the Li nucleation overpotential (34 mV at 1.0 mA cm −2 ). Moreover, the Li 3 Sb preferentially adsorbs and catalytically decomposes fluoroethylene carbonate, producing a mechanically robust, LiF‐rich SEI. Consequently, the Li 3 Sb@Cu enables stable Li plating/stripping for over 800 h and achieves an average Coulombic efficiency of 98.2% over 180 cycles. When paired with a LiFePO 4 cathode, the full cell delivers a high discharge capacity of 137.4 mAh g −1 and retains 96.6% capacity after 130 cycles at 1 C. This work presents a synergistically bifunctional interlayer on Cu foils that regulates Li nucleation and stabilizes the SEI for high‐performance LMBs.