Ultrathin hydrophobic anode/electrolyte interphase for stable zinc-metal anode
Aqueous Zn-ion batteries (AZIBs) are promising for next-generation energy storage due to high safety and low cost, but their practical use is limited by Zn dendrite growth and side reactions. An ideal anode/electrolyte interphase should block water contact while enabling fast Zn2+ transport, yet conventional thick interphases increase ionic resistance and polarization. Here, we report a hydrophobic yet ultrathin (~5 nm) polydimethylsiloxane (PDMS) artificial interphase fabricated via conformal coating. The oxygen-rich PDMS layer selectively coordinates Zn2+ while its superhydrophobicity excludes water, and the ultrathin nature enables rapid Zn2+ conduction, enhancing the Zn2+ transference number by 2.28-fold. This synergistic design suppresses dendrites and mitigates hydrogen evolution. The PDMS-modified anode achieves 99.9% Coulombic efficiency over 3500 cycles, 880-hour symmetrical cell operation at 60% depth of discharge, and 2500-cycle full-cell endurance under lean Zn conditions (N/P ratio 5.7). Proof-of-concept pouch cells sustain 1400 cycles with a 0.01% decay rate. This molecular-scale interphase strategy provides a feasible pathway toward practical AZIB implementation.