Repulsive anode interface for high-energy and safe lithium metal batteries

Metallic lithium (Li) anodes represent a tantalizing frontier in high-capacity battery design, yet their potential has long been undermined by catastrophic dendrite formation. Here, we exploit the extremely high interfacial energy between nanoscale tungsten (W) and Li to mitigate Li dendritic growth and promote compact grain formation to densify the Li metal deposits. By implementing an ultrathin 9 µm separator featuring dual W and boehmite (γ-AlO(OH)) coatings alongside a conventional carbonate electrolyte, Li metal batteries (LMBs) demonstrate exceptional performance: extended cyclability (78.9%@400cycles), fast-charging capabilities (6C, 18 mA cm−2), and prolonged calendar life. Remarkably, the outstanding thermal stability prevents thermal runaway under abusive conditions (140 ºC, 4.3 V). In practical fast-charge/slow-discharge scenarios (1.3C/0.3C), 2-stack pouch-cells operated under highly constrained conditions—limited Li metal (N/P ratio: 1.0) and lean electrolyte (E/C ratio: 2.2 g Ah−1)—achieved 82.2% capacity retention after 118 cycles. This study elucidates that interfacial energy control is the key to unlock the full potential of Li metal anodes.