Multivariate Competitive Coordination Structure in Hydrated Eutectic Electrolytes for Ultra‐Long Low‐Temperature Aqueous Zinc‐Ion Electrochemistry

Abstract Owing to high energy density and low cost, zinc‐ion batteries are gaining much popularity. However, frozen aqueous electrolytes and unstable interface hinder their practical application at extremely low temperature conditions. Herein, a multivariate competitive coordination structure in hydrated eutectic electrolytes is proposed to decrease the freezing point and concurrently construct a stable interface for long‐life low‐temperature applications. The introduction of second metal cations and organic additives not only breaks the hydrogen‐bond network of original water molecules but also competes to reshape Zn 2+ solvation shell. To be a result, free water content is decreased, and a stable solid electrolyte interface layer is simultaneously formed. Concomitantly, dendrite‐free Zn deposition and excellent Zn plating/stripping at −40 °C are achieved. Impressively, the Zn || Zn symmetrical cells with a competitive hydrated eutectic electrolyte demonstrate a stable cycle life of up to 4250 h at a current density of 0.5 mA cm −2 , and even work for ≈1000 h at a discharge depth of 62%. This work provides a unique view of designing anti‐freezing electrolytes for zinc‐ion batteries, and its universality and applicability will arouse the interest of a series of researchers in the field of electrochemical energy storage.