Sieving-type Electric Double Layer with Hydrogen Bond Interlocking to Stable Zinc Metal Anode

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc metal batteries face stability challenges due to side reactions and dendrite growth at the anode interface.
• Water and sulfate anions are key contributors to these detrimental interfacial phenomena.

Purpose of the Study:

• To enhance the stability of aqueous zinc metal batteries by mitigating side reactions and dendrite formation.
• To introduce a novel additive, 2,2 '-Sulfonyldiethanol (SDE), for constructing a protective electric double layer (EDL) at the zinc anode.

Main Methods:

• Addition of 2,2 '-Sulfonyldiethanol (SDE) to aqueous zinc sulfate electrolyte.
• Formation of a sieving-type EDL through hydrogen bond interactions.
• Analysis of interfacial ion dynamics and zinc deposition behavior.

Main Results:

• SDE effectively replaces and traps water and sulfate anions at the zinc anode interface, reducing their detrimental effects.
• The additive promotes dendrite-free zinc deposition and enhances the transference number of Zn2+ ions.
• Zn//Zn symmetrical cells demonstrated stability exceeding 3500 hours, and Zn//MnO2 full cells achieved over 2500 cycles.

Conclusions:

• The developed SDE-modified electrolyte significantly improves the cycling stability and lifespan of aqueous zinc metal batteries.
• SDE acts as a multifunctional additive, creating a protective EDL that suppresses interfacial side reactions and promotes uniform zinc plating.