Phase-Behavior-Driven Hydrogen-Bond Engineering Enables Temperature-Resilient Fibrous Zinc-Ion Batteries.

Abstract

Fibrous energy-storage systems serve as a core component in the next-generation flexible and wearable electronics, yet their practical application is hindered by the limited temperature resilience of aqueous electrolytes and the mechanically fragile electrolyte-electrode interfaces. Herein, we design an in situ deep-eutectic hydrogel electrolyte based on a hydroxyl-rich glycerol-ethylene glycol-H₂O system, in which the hydrogen-bond network is engineered to modulate the chemical potential of water and the free-energy landscape governing phase transitions. Strong H₂O-H₂O H-bonds are converted into a more uniformly distributed weak H-bond network in the electrolyte, thereby reducing the thermodynamic driving force for ice formation at low temperatures while suppressing H₂O volatilization at elevated temperatures. Meanwhile, in situ photopolymerization enables the direct formation of a conformal hydrogel layer on the electrode surface, improving interfacial adhesion and mitigating parasitic reactions such as hydrogen evolution and Zn corrosion. Benefiting from the coupled thermodynamic and interfacial regulation, Zn||PANI coin cell exhibits stable operation over an ultrawide temperature range of -50°C-100°C and delivers a cycling life exceeding 10 000 cycles with 86.71% capacity retention at 25°C. A fibrous Zn||PANI cell further maintains reliable cycling for over 500 cycles at -25°C, demonstrating the applicability of this strategy for temperature-resilient wearable energy-storage systems.