Constructing In Situ Solid Electrolyte Interphase via Hierarchical Desolvation Engineering for Ultrastable Aqueous Zinc‐Ion Batteries

Abstract Rechargeable aqueous zinc‐ion batteries (AZIBs) are promising for grid‐scale energy storage due to their high safety, low cost, and environmental friendliness. However, the lack of a stable solid electrolyte interphase (SEI) leads to dendrite growth and parasitic reactions on zinc anodes. This work introduces an ultrathin microporous polymer coating (PIM‐14) as an artificial SEI that isolates the electrolyte from the anode while facilitating ordered Zn 2+ transport. The dual functional groups (─C≡N and ─O─) in PIM‐14 synergistically regulate Zn 2+ solvation: ─C≡N coordinates Zn 2+ for primary desolvation, while ─O─ disrupts the solvation shell via hydrogen bonding, enabling secondary desolvation. This process creates a local high‐pH environment, promoting in situ formation of a ≈10 nm thick, ion‐conductive Zn(OH) 2 /ZnO SEI. The dual protection results in an ultralow nucleation overpotential (25 mV), high Coulombic efficiency (99.36% over 500 cycles), and exceptional stability—over 5500 h in symmetric batteries and 192 mAh g −1 after 500 cycles in V 2 O 5 full batteries. This work pioneers a solvation‐mediated in situ SEI strategy for dendrite‐free AZIBs.