Coupling Dead‐Lithium Reactivation and Interfacial Stabilization for Long‐Life Lithium Metal Batteries

ABSTRACT Lithium metal batteries (LMBs) experience poor cycling stability mainly due to the interfacial instability of the lithium metal anode and the unavoidable accumulation of electrochemically inactive dead lithium. Here, we report a multifunctional Li ₃ Bi&LiI composite artificial anode interphase that forms in situ via a simple one‐step interfacial reaction between BiI ₃ and lithium metal. This architecture combines the functions of Li ₃ Bi for interfacial coupling and mechanical strength with LiI to improve Li ⁺ transport, extend the Sand's time, and ensure uniform lithium deposition. More importantly, partially dissolved LiI enables a reversible I ⁻ /I ₃ ⁻ redox process that continuously reactivates dead lithium into cyclable Li ⁺ , directly addressing lithium inventory loss. Benefiting from the synergistic coupling of interfacial stabilization and lithium recycling, the optimized lithium anode achieves ultra‐long dendrite‐free cycling exceeding 10 000 h and maintains stable operation >450 h even at an ultrahigh current density of 10 mA cm ⁻² . When paired with a LiFePO ₄ cathode, the LMB retains a 94.4% capacity retention after 500 cycles. This work integrates interfacial stabilization with active lithium recycling in a single protective design, offering a viable strategy toward long‐life LMBs.