Triple-function Hydrated Eutectic Electrolyte for Enhanced Aqueous Zinc Batteries

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 H2O is inhibited by reconstructing hydrogen bonds due to the strong interaction between TMS and H2O. 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 Zn2+ 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 (NH4V4O10, (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.

Automated summary

A triple-functional strategy is reported to improve the problems faced by aqueous rechargeable zinc-ion batteries (ARZBs) by introducing tetramethylene sulfone (TMS) to form a hydrated eutectic electrolyte. This strategy inhibits the activity of H2O, increases the thickness of the double electric layer (EDL) structure on the zinc (Zn) surface, and achieves a novel solvent co-intercalation mechanism. As a result, the Zn||NVO battery exhibits a remarkably high specific capacity of 515.6 mAh g(-1) for over 40 days. This multi-functional electrolytes and solvent co-intercalation mechanism will significantly propel the practical development of aqueous batteries.