Solvent Engineering‐Driven Anion Chemistry Enables Stable Zn Interfaces for Wide‐Temperature Aqueous Zinc Batteries

Abstract Aqueous zinc‐ion batteries are intrinsically safe and cost‐effective, yet their practical deployment is hindered by uncontrolled interfacial reactions and poor temperature resilience. While solvent engineering has been employed to suppress water activity, prior efforts have predominantly focused on modulating Zn 2 ⁺ solvation while neglecting critical anion‐solvent interactions. Here, a solvent‐tailored triflate electrolyte (STTE) is designed that leverages the interplay between ether solvents and CF 3 SO 3 − to direct anion decomposition chemistry. Ether‐solvent dynamically stabilizes anion‐derived intermediates, promoting the formation of a compact organic/inorganic dual‐layer solid‐electrolytes interphase. Notably, the ether‐induced stabilization modulates the anion decomposition thermodynamics, restricting excessive organic byproduct formation and preventing the growth of structurally heterogeneous organic–inorganic derivatives that typically compromise interfacial stability. The optimized STTE enables exceptional Zn anode performance, achieving ultralong cycling (3500 h at 25 °C; 1200 h at −60 °C) and high depth‐of‐discharge (68% at 10 mA cm −2 , 20 mAh cm −2 ). Full cells paired with NaV 3 O 8 ·1.5H 2 O maintain 90% capacity after 500 cycles at room temperature (0.2 A g −1 ) and retain 95.8%/≈100% capacity at 50 °C/−30 °C. The Ah‐level pouch cell delivers 84.3% capacity retention over 37 cycles. This work highlights solvent‐anion synegy paradigms, offering a universal strategy to design robust interphases for aqueous batteries in extreme environments.