<p>Aqueous Zn-ion batteries (AZIBs) emerge as promising candidates for next-generation energy storage owing to its inherent high safety. However, their practical implementation is impeded by rampant Zn dendrite growth and corrosive side reactions, originating from the lack of durable interphases to regulate ion flux and shield against electrolyte erosion. While interfacial layer engineering manifests great success, conventional thick modification layers inevitably exacerbate ionic conduction barriers and interfacial polarization, particularly problematic for hydrophobic coatings. Herein, we construct hydrophobic yet ultrathin (∼5 nm) polydimethylsiloxane (PDMS) artificial interphase leveraging its intrinsic elastic property and excellent conformal coating capability. The oxygen-enriched PDMS layer enables selective Zn²⁺ coordination, while its superhydrophobicity excludes solvent H₂O penetration. The ultrathin characteristic allows rapid Zn²⁺ conduction with a 2.28-fold enhancement in Zn²⁺ transference number. Thus, synergistic dendrite suppression and H₂ evolution mitigation are realized. The PDMS-modified anode achieves unprecedented cycling stability with 99.9% Coulombic efficiency over 3500 cycles, 880-h symmetrical cell operation under 60% depth of discharge, and 2500-cycle full-cell endurance with lean Zn source. Proof-of-concept pouch cells maintain robust 1400 cycles with 0.01% decay rate. Our molecular-scale interphase strategy establishes a feasible pathway toward practical AZIB implementation.</p>