Hydrogen Bond Reconstruction Maneuver in Eutectic Electrolyte Enables Ultralong-Lifespan Zinc-Ion Batteries

Eutectic electrolytes (EEs) serve as a kind of ionic liquid-analogue electrolytes, newly emerging due to their low cost, high stability, biodegradability, nonflammability, and easy preparation properties. The commonly used quaternary ammonium salts play the role of acceptors to form hydrogen bonds (HBs), while the inorganic anions are mostly anchored. Herein, a new type of choline-chloride-based EE was prepared by reshaping the HB donor-acceptor identity to unconstrain chloride anions. Multiple spectral characterizations combined with theoretical analysis confirm the existence of reconstructed HBs and the formation of an anion-dominated solvation structure. Consequently, an organic-inorganic hybrid solid electrolyte interphase film was created on the Zn surface, realizing dendrite-free Zn anodes and achieving an ultralong lifespan of 18175 h (∼2.07 years) of highly reversible Zn plating/stripping performance at a current density of 0.5 mA cm^-2, even a super high cumulative capacity of 42 Ah cm^-2 at 20 mA cm^-2. Furthermore, the assembled Zn || AC@I₂ pouch cell shows stable rate and cycling electrochemical properties. This research sheds new light on developing EEs for high-safety and practical zinc-ion batteries.