Gradient Structured Separator Enables Stable Aqueous Zinc Metal Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Developing stable aqueous zinc-ion batteries is crucial for sustainable energy storage.
• Zinc dendrite growth and parasitic side reactions hinder battery performance and lifespan.
• Functional separators are key to improving electrochemical performance by controlling ion transport and preventing undesirable reactions.

Purpose of the Study:

• To design and fabricate a functional separator with a gradient structure for aqueous zinc-ion batteries.
• To investigate the separator's ability to suppress zinc dendrite growth and parasitic side reactions.
• To enhance the electrochemical performance and cycling stability of zinc anodes.

Main Methods:

• Fabrication of a functional separator using cerium fluoride (CeF3) nanoparticles functionalized glass fibers.
• Experimental characterization of the separator's structure and properties.
• Electrochemical testing of Zn||Zn cells with the functional separator, including long-term cycling stability tests.
• Theoretical calculations to understand ion transport mechanisms.

Main Results:

• The functional separator exhibits a gradient structure that effectively tailors Zn2+ flux and restrains SO42- transport.
• The CeF3 nanoparticles promote dense zinc deposition and suppress side reactions through interaction with water molecules.
• The modified Zn||Zn cells demonstrated excellent cycling stability, achieving 2500 hours at 1 mA cm-2 and 1 mAh cm-2, and 1000 hours at 5 mA cm-2 and 5 mAh cm-2.

Conclusions:

• The developed CeF3-functionalized gradient separator is a promising strategy for advancing aqueous zinc-ion battery technology.
• This separator design effectively addresses key challenges like dendrite formation and side reactions.
• The findings offer a new solution for developing high-performance and long-lasting aqueous zinc-ion batteries.