Dual-Strong Ligand Intervention for Extreme-Condition Aqueous Zn Batteries

Aqueous zinc-ion batteries (ZIBs) hold promises for large-scale energy storage. However, critical challenges in aqueous zinc-ion electrolytes—freezing, side reactions, and sluggish Zn ²⁺ kinetics—persist because single-track strategies fail to balance fast desolvation, interphase stability, and low-temperature performance. Traditional approaches that modify co-solvents to tune Zn ²⁺ –H ₂ O coordination often fail to further adjust solvation strength and overlook solvent–solvent interactions. Hence, we propose a dual-strong ligand strategy that lowers the Zn²⁺ desolvation barrier and broadens temperature performance by pairing two co-solvents with distinct coordination strengths. Urea, of intermediate Zn ²⁺ affinity and strong H-bond donation, disrupts Zn ²⁺ –strong co-solvent/ H ₂ O interactions to tune solvation. Electrochemical tests and theoretical calculations confirmed the accelerated Zn ²⁺ desolvation at the electrode/electrolyte interface, improving battery performance from room temperature to − 40°C. The designed electrolyte exhibited remarkable stability, achieving a lifespan of 3000 hours in Zn//Zn symmetric cells and an average Coulombic efficiency (CE) of 99.2% over 7500 cycles in Zn//Cu asymmetric cells at − 40°C. Furthermore, Zn//NaV ₃ O ₈ ·1.5H ₂ O (NVO) full cells using the designed electrolyte maintained long-term performance for 2400 cycles at − 40°C. These results highlight the effectiveness of the dual-strong ligand intervention in enabling high-performance ZIBs across a broad temperature range.