Extremophile-Inspired Hydroxyectoine Reconstructs Water Networks and Stabilizes Zinc Interfaces in Aqueous Zinc Batteries.

AZIBs are promising for large‑scale energy storage, yet their practical deployment is severely limited by H2 evolution, interfacial corrosion, and dendritic Zn growth. Herein, inspired by the water-regulation strategy of extremophiles, hydroxyectoine (HE), a natural solute with strong hydration capability, is introduced for the first time as a multifunctional electrolyte additive for AZIBs. HE enables a dual-phase regulation strategy by simultaneously modulating the electrolyte hydrogen-bonding network and stabilizing the zinc electrode interface. Experimental characterizations and theoretical calculations reveal that HE reconstructs the water hydrogen-bonding environment, reduces free water activity, and participates in Zn2+ solvation regulation, thereby suppressing parasitic hydrogen evolution and facilitating Zn2+ desolvation. Meanwhile, HE preferentially interacts with the Zn surface and modifies the interfacial environment, promoting more uniform Zn deposition. Benefiting from these synergistic effects, the Zn||Zn symmetric cells deliver ultralong cycling stability over 7300 h at 5.0 mA cm-2 and achieve an accumulated plating capacity of 18.25 Ah cm-2. Zn||Cu cells maintain a high average Coulombic efficiency of 99.73% over 1500 cycles, while Zn-based full cells retain 70.86% of their initial capacity after 3000 cycles at 5.0 A g-1. This bio-inspired electrolyte design offers a robust route to durable, high-performance AZIBs.