Aqueous eutectic electrolyte-derived organic/inorganic hybrid interphase towards reversible zinc electrochemistry for long-life zinc ion batteries
Aqueous zinc ion batteries (ZIBs) offer intrinsic safety and cost advantages for grid-scale energy storage, yet their practical deployment is constrained by parasitic reactions, poor anode stability, and dendritic zinc growth. This study introduces a ternary aqueous eutectic electrolyte composed of N-ethylacetamide (Nea), H2O, and Zn(OTf)2 to mitigate these failure modes. The Nea molecules preferentially adsorb on the zinc anode, establishing a uniform interfacial electric field and a de-watering shielding layer that suppresses side reactions. Concurrently, an organic/inorganic hybrid solid electrolyte interphase (SEI) forms in situ, inhibiting the tip effect and promoting homogeneous Zn2+ diffusion and deposition. The Zn//Zn symmetric cell achieves 4590 h cycling at 0.5 mA cm−2/0.5 mAh cm−2 and a depth of discharge of 85.4% at 1.0 mA cm−2/5.0 mAh cm−2. Full cells with a V2O5·1.6H2O cathode deliver over 5000 cycles with Coulombic efficiency near 100% at 1.0 and 2.0 A g−1. These results demonstrate that eutectic electrolyte engineering can simultaneously address dendrite formation and interfacial side reactions, providing a viable pathway for long-life aqueous ZIBs.