A Diffusion-Retarded Strategy for Practical Zn-I₂ Batteries Under Harsh Conditions.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Zinc-iodine (Zn-I2) batteries offer inherent safety and cost-effectiveness.
• Key challenges include sluggish iodine kinetics and the polyiodide shuttle effect, hindering practical application.

Purpose of the Study:

• To develop a diffusion-retarded strategy for enhancing Zn-I2 battery performance.
• To address polyiodide shuttle and accelerate iodine species reaction kinetics.

Main Methods:

• Carbon cage-encapsulated Cu-doped ZnO nanoparticles on carbon paper as iodine cathodes.
• Utilizing a physical barrier and catalytic Cu-ZnO sites to manage polyiodides and iodine species.
• Testing battery performance under various conditions, including high current densities and extreme temperatures.

Main Results:

• Achieved ultra-low polarization voltage (26.7 mV at 1 A g-1) and ultra-long cycle life (>40,000 cycles at 5 A g-1).
• Demonstrated remarkable stability at elevated temperatures (5000 cycles, 0.007% degradation/cycle at 60 °C).
• Showcased stable operation at sub-zero temperatures and with a low negative/positive (N/P) ratio (2.5).

Conclusions:

• The diffusion-retarded strategy effectively enhances Zn-I2 battery performance and stability.
• Rational cathode design is crucial for developing practical Zn-I2 battery systems.
• The developed materials offer a promising pathway for high-performance batteries under demanding conditions.