Gravity‐Assisted Infiltration Enables a Spatially Extended and Dynamically Stable Multi‐Phase Interface in Air Cathodes for Practical Lithium–Air Batteries

ABSTRACT Li–air batteries (LABs) have attracted considerable attention as next‐generation energy‐storage systems because of their exceptionally high theoretical energy density. However, their practical application remains limited by the difficulty of sustaining an effective multi‐phase interface (MPI), where Li ⁺ , O ₂ , and e ⁻ converge to drive the reversible formation and decomposition of discharge products. Herein, we report a simple and scalable gravity‐assisted infiltration (GAI) strategy for fabricating air cathodes, in which catalysts are anchored throughout the gas diffusion layer framework. This architecture enables continuous Li ⁺ /O ₂ /e ⁻ transport pathways and establishes a spatially extended and stable MPI across the cathode thickness, while remaining binder‐free and requiring less electrolyte. As a result, LABs with the GAI cathode exhibit lower overpotentials and longer cycling (>300 cycles), while still exhibiting superior performance at a high cathode loading of 3.0 mg cm ⁻² . In situ EIS/DRT/DCT and depth TOF‐SIMS reveal stable interfacial evolution and a nucleation‐preferred discharge‐product formation mechanism, evidencing a spatially extended and dynamically stable MPI across the cathode thickness. The resulting LABs further deliver high full discharge/charge capacity of ∼24 mA h cm ⁻² , improved low‐temperature (−20°C) mass transport, enhanced high temperature (60°C) stability, and promising pouch cells with high‐energy density (798.80 Wh kg ⁻¹ ).