Hydroxyl‐Rich Hyperbranched Polyglycerol Additive for Low‐Temperature Aqueous Zinc Batteries: Sustained and Efficient Dehydration and High‐Conductivity

Abstract The development of aqueous Zn‐ion batteries operable at subzero temperatures is impeded by a number of design problems, including slow ion transport and interfacial instability. Drawing inspiration from marine fish adapted to polar waters, a bioinspired supramolecular additive hyperbranched polyglycerol, CDhPG is developed, that integrates dual biomimetic functions, thus overcoming the design limitations of Zn‐ion batteries. Specifically, CDhPG mimics the ice‐binding behavior of antifreeze proteins and the dehydration microenvironment of potassium ion channels, enabling simultaneous inhibition of ice growth and acceleration of Zn 2+ desolvation. The hydroxyl‐rich architecture facilitates strong hydrogen bonding with ice surfaces, while its internal cavities promote selective Zn 2+ coordination, thereby remodelling both the ice‐water and Zn‐electrolyte interfaces. As a result, the ZnCl 2 ‐CDhPG electrolyte exhibits a suppressed freezing point (below −40 °C) and enables dendrite‐free Zn deposition. The Zn//Zn cells are found to deliver stable cycling over 900 hrs at −40 °C (5 mA cm −2 , 43% DOD), and the full cells retain high capacity after 500 cycles at −40 °C. The bio‐inspired, dual‐functional strategy described here offers a generalizable approach for designing low‐temperature electrolytes in aqueous energy storage systems.