A Binary Hydrate-Melt Electrolyte with Acetate-Oriented Cross-Linking Solvation Shells for Stable Zinc Anodes.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc-ion batteries (ZIBs) offer low cost and high safety.
• Metal Zn anodes in ZIBs face challenges like low coulombic efficiency and poor cycling due to side reactions.

Purpose of the Study:

• To design a novel electrolyte for ZIBs that suppresses hydrogen evolution and by-product formation on Zn anodes.
• To improve the coulombic efficiency and cycling performance of Zn anodes in aqueous ZIBs.

Main Methods:

• A binary hydrate-melt electrolyte composed of ZnCl2/Zn(OAc)2 was synthesized.
• The Zn2+ solvation structure was adjusted to weaken Zn2+-H2O interactions and suppress water activity.
• Zn||p-chloranil cells were assembled using the novel electrolyte for performance evaluation.

Main Results:

• The ZnCl2/Zn(OAc)2 electrolyte effectively suppressed side reactions on Zn anodes.
• A high coulombic efficiency of 99.59% was achieved for Zn anodes.
• Zn||p-chloranil cells with the new electrolyte demonstrated enhanced cycling performance compared to conventional electrolytes.

Conclusions:

• The designed hydrate-melt electrolyte significantly improves Zn anode stability and performance in aqueous ZIBs.
• This electrolyte offers a promising strategy for developing high-performance and safe ZIBs.
• The findings pave the way for practical applications of ZIBs in energy storage.