Enabling selective zinc-ion intercalation by a eutectic electrolyte for practical anodeless zinc batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc metal batteries face challenges with proton co-intercalation at cathodes and zinc dendrite growth at anodes, limiting their use in stationary storage.
• These issues trigger parasitic electrolyte reactions, reducing battery lifespan and performance.

Purpose of the Study:

• To investigate the competition between zinc-ion and proton intercalation chemistry in oxide cathodes.
• To develop a cost-effective, non-flammable hybrid eutectic electrolyte to suppress side reactions and stabilize zinc metal anodes.
• To enhance the performance and longevity of aqueous zinc batteries for sustainable energy storage.

Main Methods:

• Utilized ex-situ and operando techniques to analyze Zn2+ vs. proton intercalation at oxide cathodes.
• Developed and tested a novel hybrid eutectic electrolyte for aqueous zinc batteries.
• Evaluated zinc plating/stripping behavior and coulombic efficiency at high areal capacities.
• Assessed the cycling stability of anode-free zinc-ion cells and Zn||Iodine full cells.

Main Results:

• The hybrid eutectic electrolyte effectively suppressed side reactions and enabled dendrite-free zinc plating/stripping with 99.8% coulombic efficiency at 4 mAh cm-2.
• Anode-free zinc-ion cells demonstrated a benchmark performance, retaining 85% capacity over 100 cycles at 25°C.
• Zn||Iodine full cells achieved 86% capacity retention over 2500 cycles using the developed electrolyte.

Conclusions:

• The developed hybrid eutectic electrolyte is a promising solution for stabilizing zinc redox reactions at both electrodes in aqueous zinc batteries.
• This approach paves the way for high-performance, long-duration energy storage systems, particularly for stationary applications.
• The study highlights a new avenue for advancing sustainable energy storage technologies.