Hydroxyl-Rich Hyperbranched Polyglycerol Additive for Low-Temperature Aqueous Zinc Batteries: Sustained and Efficient...

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 Zn²⁺ desolvation. The hydroxyl-rich architecture facilitates strong hydrogen bonding with ice surfaces, while its internal cavities promote selective Zn²⁺ coordination, thereby remodelling both the ice-water and Zn-electrolyte interfaces. As a result, the ZnCl₂-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.