Atmosphere Adaptive Lithium–Air Batteries Enabled by Thermodynamically Self‐Limiting Salt‐Free Electrolytes

The practical viability of lithium–air batteries (LABs) in semi‐open systems is severely hindered by the hygroscopic nature of extrinsic lithium salts, which trigger parasitic reactions. Herein, we report a shift from traditional salt addition to an intrinsic ion‐generation strategy by designing a thermodynamically self‐limiting, salt‐free electrolyte (SLE). By harnessing the interfacial reactivity between EMIMTFSI and the lithium anode, we elucidate a dual‐pathway mechanism involving radical cleavage and dealkylation coordination. This in situ self‐lithiation kinetically halts after involving only ∼11% of the EMIM + species, while metallic lithium oxidation generates intrinsic Li + carriers and constructs an organic–inorganic mosaic solid electrolyte interphase enriched with lithium carbide‐related species, LiF, and Li 3 N. This hydrophobic microenvironment regulates the permeation of atmospheric species and modulates discharge‐product chemistry through trace moisture and CO 2 . Consequently, SLE‐based batteries exhibit atmosphere‐adaptive electrochemistry, delivering a lifespan exceeding 280 h in ambient air and outperforming the pure‐oxygen system (218 h). Mechanistic analyses further indicate that terminal cell failure is associated with solvation‐induced kinetic freezing rather than dominant chemical degradation. This work establishes a framework for exploiting controlled interfacial reactivity toward self‐adaptive energy storage in ambient environments.