Unlocking cryogenic zinc-ion batteries with a glycerol monoallyl ether-modulated aqueous electrolyte

Abstract

Aqueous zinc-ion batteries (AZIBs) face critical challenges including zinc anode/electrolyte interfacial instability inducing capacity fading and cycle life degradation and operational failure at sub-zero temperatures due to electrolyte freezing. To address these limitations, we employed 3-allyloxy-1,2-propanediol (AP) as a multifunctional electrolyte cosolvent. The AP synergistically depresses the electrolyte freezing point via disruption of the water hydrogen-bonding network. Concurrently, alcoholic hydroxyl groups in AP preferentially adsorb onto the zinc anode, directing oriented Zn(002) plane growth to enable uniform and dendrite-free zinc deposition. Furthermore, oxygen atoms of AP restructure Zn²⁺ solvation sheaths, weakening H₂O–Zn²⁺ coordination bonds while suppressing water activity. Through systematic optimization of the water-to-AP ratio and combined experimental–theoretical analysis, we elucidated Zn²⁺ behavior from solvation thermodynamics to deposition kinetics. The optimized AP-10% electrolyte enables a Zn∥Zn symmetric cell to achieve exceptional cycling stability (4500 h at 1.0 mA cm⁻²/1.0 mAh cm⁻², 25 °C). The Zn∥NVO full cells with AP-10% electrolyte retain capacity after 1650 cycles at 2.0 A g⁻¹. The electrolyte also exhibits sustained operation for 2500 h in Zn∥Zn symmetric cells at −20 °C. This work establishes an integrated electrolyte design strategy that simultaneously addresses dendrite suppression, parasitic reaction mitigation, and low-temperature cryogenic operation, advancing practical AZIBs for cryogenic energy storage applications.