Enabling a Robust Long-Life Zinc-Iodine Flow Battery by Stabilizing the Zinc Anode in a Halide-Rich Electrolyte

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Grid-scale energy storage requires safe, low-cost solutions like zinc-iodine flow batteries (ZIFBs).
• Practical ZIFB application is limited by solid iodine precipitation and zinc dendrite growth.
• Halide-rich electrolytes address iodine issues, but anode instability persists.

Purpose of the Study:

• To develop a holistic solution for ZIFB anode instability.
• To improve the durability and practicality of zinc-iodine flow batteries.

Main Methods:

• Introduction of glucosamine sulfate (GS) as a dual-function additive in a halide-rich electrolyte.
• Investigation of GS's effect on Zn2+ solvation structure and anode surface adsorption.
• Testing ZIFB performance with a zero-excess zinc anode and anolyte.

Main Results:

• GS reconfigures Zn2+ solvation, accelerating deposition kinetics.
• GS forms a water-poor layer on the anode, inhibiting side reactions and promoting uniform Zn (002) deposition.
• The ZIFB demonstrated over 500 cycles at 40 mA cm-2 and 30 mAh cm-2, with 15 Ah cm-2 cumulative plating capacity, 99.6% Coulombic efficiency, and 81.9% energy efficiency.

Conclusions:

• Glucosamine sulfate effectively stabilizes the zinc anode in ZIFBs.
• This electrolyte engineering strategy significantly enhances ZIFB durability and performance.
• The findings pave the way for practical, high-energy flow batteries.