Synergistic Coupling of Host and Electrolyte Achieving 1270 Wh L ⁻¹ in Anode‐Free Lithium Metal Batteries

Anode-free lithium metal batteries (LMBs) represent a promising avenue for maximizing energy density by eliminating excess lithium (Li), yet their practical implementation is impeded by limited Li reversibility and pronounced interfacial instability. Herein, a synergistic coupling strategy is reported that integrates a highly reversible host (RH) with a rationally designed, carbonate-rich electrolyte (DEL) to concurrently address these fundamental challenges. The RH spontaneously induces the formation of a robust Li₂O- and Li₃N-rich solid electrolyte interphase via electron transfer, which effectively accommodates Li volume changes and suppresses dendritic growth. Complementarily, DEL, composed of commercially available salts, solvents, and additives, establishes stable electrode-electrolyte interphases at both electrodes. Coin-type anode-free full cells employing the RH-DEL configuration achieve an average Coulombic efficiency of 99.6% and 81.9% capacity retention after 100 cycles at 4.6 mAh cm^-2 and 2.3 mA cm^-2. Stacked pouch-type full cells further deliver a record volumetric energy density of 1270 Wh L^-1 (including packaging) under lean electrolyte (E/C = 2.5 g Ah^-1) and a low stack pressure (≈20 kPa). This synergistic approach delineates a practical pathway toward high-energy, long-life anode-free LMBs for advanced energy storage systems.