Non‐Covalent Molecular Engineering of Hydrogel Electrolytes via π‐Anion Confinement and Hydrogen‐Bond Reconfiguration for Wide‐Temperature and Ultra‐Stable Zn‐Ion Batteries

Abstract The practical application of Zn‐ion batteries (ZIBs) is hindered by poor cycling stability and a narrow operating temperature window, issues stemming from the unstable Zn anode and the reactive nature of aqueous electrolyte. To overcome these challenges, a functional hydrogel electrolyte is developed via copolymerization of acrylamide (AM) and 2‐phenoxyethyl acrylate (PHEA). This design utilizes a novel non‐covalent molecular engineering strategy to simultaneously regulate Zn ²⁺ transport and enhance thermal adaptability. Specifically, the electron‐deficient phenyl rings in PHEA establish favorable π‐anion interactions with OTf ^– anions, achieving a high Zn ²⁺ transference number of 0.70. Concurrently, spectroscopic analyses indicate that the oxygen‐rich groups in PHEA act as competitive hydrogen‐bond acceptors, reconstructing the hydrogel's hydrogen‐bonding network. This reconfiguration leads to tighter confinement of water molecules and a broader operational temperature range. Consequently, Zn//Zn symmetric cells demonstrate exceptional cycling durability over 6400 h at 25 °C, 2400 h at 50 °C, and 1200 h at –20 °C. When paired with Zn ₂ V ₂ O ₇ cathodes, full cells also deliver outstanding cycling performance and remarkable capacity retention across this wide temperature range. This work provides fundamental insights into non‐covalent interactions for electrolyte design and presents a scalable strategy for developing robust, temperature‐resilient energy storage.