Dendrite Suppression Membranes for Rechargeable Zinc Batteries

Area of Science:

• Electrochemistry
• Materials Science

Background:

• Aqueous zinc batteries offer a cost-effective, safe, and non-toxic alternative to lithium-ion batteries for grid storage.
• Zinc dendrite growth limits the cycle life of aqueous zinc batteries, hindering their practical application.

Purpose of the Study:

• To develop a mechanically robust, low-cost cation exchange membrane for aqueous zinc batteries.
• To enhance the cyclability and suppress dendrite formation in zinc metal anodes.

Main Methods:

• Synthesized a cross-linked polyacrylonitrile (PAN)-based cation exchange membrane via reaction with Li2S3 and subsequent hydrolysis.
• Characterized the membrane's properties, including thickness, mechanical strength, cation transport, and ionic flux distribution.
• Tested the membrane's performance in Zn/Zn symmetric cells for cyclability and dendrite suppression.

Main Results:

• Developed a thin (30 μm) and mechanically robust membrane, significantly stronger than hydrated Nafion.
• Achieved preferred cation transport and homogeneous ionic flux distribution.
• Demonstrated exceptional cyclability (>350 cycles) with low polarization and effective dendrite suppression in Zn/Zn symmetric cells.

Conclusions:

• The developed PAN-based cation exchange membrane effectively enhances the cyclability of aqueous zinc batteries.
• Designing advanced separators is a viable strategy to overcome the limitations of zinc dendrite growth.
• This work paves the way for practical grid-scale energy storage using aqueous zinc batteries.