Boosting Zn||I₂ Battery's Performance by Coating a Zeolite-Based Cation-Exchange Protecting Layer

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Zinc-iodine (Zn||I2) batteries are promising alternatives to lead-acid batteries but suffer from short lifespan due to uncontrolled triiodide (I3-) shuttling and parasitic reactions on zinc anodes.
• These detrimental processes primarily occur on the zinc anode surface, highlighting the need for effective surface modification strategies.

Purpose of the Study:

• To develop a facile and effective method for enhancing the performance and lifespan of Zn||I2 batteries.
• To suppress detrimental side reactions at the zinc anode, including triiodide shuttling, corrosion, and dendrite growth.

Main Methods:

• A zeolite-based cation-exchange protecting layer was facilely coated onto the zinc anode.
• The negatively-charged zeolite cavities facilitate Zn2+ migration while blocking anions and electrolyte.

Main Results:

• The zeolite-protected Zn||I2 batteries demonstrated suppressed triiodide shuttling, Zn corrosion, and dendrite growth.
• Achieved ultra-long cycle life with 91.92% capacity retention after 5600 cycles at 2 A g-1.
• Exhibited high average coulombic efficiencies of 99.76% and large capacities of 203-196 mAh g-1 at 0.2 A g-1.

Conclusions:

• Zeolite protecting layers provide a low-cost and effective approach to comprehensively suppress parasitic reactions on Zn anodes in aqueous batteries.
• This strategy significantly enhances the cycle life, coulombic efficiency, and capacity of Zn||I2 batteries, paving the way for high-performance energy storage solutions.