Bio-Inspired Oligocellulose-Regulated Ice-Water Interfaces Enable Sustained Ion Transport in Frozen Aqueous Zinc Batteries

While highly concentrated salts and organic components enhance the subzero performance of zinc batteries by improving electrolyte fluidity and conductivity, their high cost and environmental pollution negate the inherent sustainability and economy of aqueous electrolytes. Herein, inspired by the ice-inhibition mechanism of natural antifreeze glycoproteins, we designed oligomeric cellulose with an average degree of polymerization of 8 (OC-8). At trace concentration, OC-8 effectively suppresses ice recrystallization and induces a fourfold increase in inter-ice water channels. In situ confocal fluorescence microscopy confirms that this interconnected network boosts ion transport by nearly an order of magnitude in cryogenic electrolytes. Complementary molecular dynamics simulations coupled with CHILL⁺ structural analysis reveal that OC-8 adsorbs at the ice-water interface, perturbs interfacial hydrogen-bond ordering, and stabilizes extended quasi-liquid domains, enabling efficient Zn²⁺ transport at low temperatures. Leveraging this antifreeze mechanism, Zn||Zn cells achieve stable cycling for over 1200 h at −30°C. The full Zn||NH₄⁺-V₂O₅ cell sustains remarkable long-term stability over 3000 cycles, simultaneously suppressing zinc dendrite growth and detrimental side reactions. This work provides a fundamental mechanistic insight into saccharide-based antifreeze agents and presents a bio-inspired strategy for engineering an eco-friendly, high-performance, and durable antifreeze aqueous electrolyte.