Design of Cryogenic Electrolyte with Organic‐Free Solvation Structure for Wide‐Temperature Zinc Metal Batteries

Abstract

Abstract Albeit the promising performance at ambient temperatures, the development of zinc metal batteries (ZMBs) is still haunted by the freezing‐prone characteristic of aqueous electrolytes and the deteriorative interface reaction in extreme scenarios. Especially at low‐temperature conditions, the abundant hydrogen bonds (H‐bonds) between H 2 O molecules inevitably drive the aqueous solution transform into an orderly frozen state, resulting in sluggish reaction kinetics. Herein, a bio‐inspired cryogenic electrolyte is proposed, and the strong interaction between proline additive and H 2 O solvent effectively disrupts the H‐bond network, thereby depressing the freezing point while maintaining high ionic conductivity under extremely‐low temperatures. Furthermore, the tailored weak and organic‐free solvation structures facilitate rapid desolvation of Zn 2+ ions, and the reduced H 2 O activity mitigates parasitic reactions on Zn anode surface, thus guaranteeing reversible zinc deposition and dendrite‐free interface. Consequently, the anti‐freezing electrolyte endows Zn||Zn cells with durable cyclic behavior over 2500 h. The PANI||Zn cell demonstrates excellent temperature adaptability from −30 to 60 °C, achieving a reversible capacity of 173.6 mAh g −1 at 60 °C and maintaining 93.6% capacity retention after 1300 cycles at −30 °C. This work reports a practical electrolyte design strategy for ZMBs in harsh environments, promoting the future application of low‐temperature‐resistant aqueous batteries.