Copper‐Governed Divergence of Lithium Deposition Modes in Anode‐Free Lithium Metal Batteries

ABSTRACT Anode‐free lithium metal batteries (AFLMBs) maximize energy density by eliminating anode host materials, but their lifetime is governed by Li deposition on the current collector (CC)—a heterogeneous nucleation and growth process. Current research mainly focuses on electrolyte or artificial interphase engineering, whereas how the CC's physical structure dictates initial deposition behavior remains unclear. Here, we show that the microstructure of Cu foils induces two distinct Li deposition modes: localized nucleation‐selective growth (LS) and distributed nucleation‐competitive coalescence (DCC). Using HLCu and nmCu as model interfaces, we elucidate the evolution pathways of these modes. By integrating AFM, iSCAT, ToF‐SIMS and operando EIS‐DRT, we reveal mode‐specific differences in nucleation sites, interfacial kinetics, and the coupling between morphology, mechanical response, and side reactions. The LS mode generates loose, non‐uniform Li deposits with strong gas evolution, whereas the DCC mode enables dense, continuous, and kinetically stable Li layers. This work demonstrates that the CC is not a passive substrate but a critical component that determines the deposition mode and performance degradation. Optimizing the physical structure of the CC interface offers a key strategy—beyond electrolyte and interphase design—for long‐life AFLMBs.