Triple‐function Hydrated Eutectic Electrolyte for Enhanced Aqueous Zinc Batteries

Abstract Aqueous rechargeable zinc‐ion batteries (ARZBs) are impeded by the mutual problems of unstable cathode, electrolyte parasitic reactions, and dendritic growth of zinc (Zn) anode. Herein, a triple‐functional strategy by introducing the tetramethylene sulfone (TMS) to form a hydrated eutectic electrolyte is reported to ameliorate these issues. The activity of H 2 O is inhibited by reconstructing hydrogen bonds due to the strong interaction between TMS and H 2 O. Meanwhile, the preferentially adsorbed TMS on the Zn surface increases the thickness of double electric layer (EDL) structure, which provides a shielding buffer layer to suppress dendrite growth. Interestingly, TMS modulates the primary solvation shell of Zn 2+ ultimately to achieve a novel solvent co‐intercalation ((Zn‐TMS) 2+ ) mechanism, and the intercalated TMS works as a “pillar” that provides more zincophilic sites and stabilizes the structure of cathode (NH 4 V 4 O 10 , (NVO)). Consequently, the Zn||NVO battery exhibits a remarkably high specific capacity of 515.6 mAh g −1 at a low current density of 0.2 A g −1 for over 40 days. This multi‐functional electrolytes and solvent co‐intercalation mechanism will significantly propel the practical development of aqueous batteries.