Anchoring polyiodide with flexible interlayer for high-performance aqueous zinc-iodine batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Zinc-iodide (Zn-I₂) batteries offer low cost, high capacity, and safety.
• Challenges include polyiodide shuttle and slow iodine redox kinetics, hindering practical use.

Purpose of the Study:

• To design an efficient interlayer for Zn-I₂ batteries.
• To address polyiodide dissolution and sluggish iodine redox kinetics.

Main Methods:

• Fabrication of a freestanding carbon nanofibers (CNFs) membrane embedded with ultrafine tin nanoparticles (uSn-CNFs).
• Utilizing experimental and theoretical analyses to evaluate interlayer performance.
• Integrating CNFs with Sn nanoparticles for synergistic effects.

Main Results:

• Ultrafine Sn nanoparticles (approx. 10 nm) offer active sites for polyiodide chemisorption and electrocatalytic conversion.
• CNFs provide physical inhibition, capturing and enabling rapid conversion of iodine species.
• Batteries with uSn-CNFs interlayers demonstrated exceptional cycling stability (0.0005% degradation per cycle over 30,000 cycles at 10 C) and rate capability (176 mAh g^-1 at 5 C).

Conclusions:

• The uSn-CNFs interlayer effectively suppresses polyiodide shuttle and accelerates iodine redox kinetics.
• This interlayer design significantly enhances the performance and stability of Zn-I₂ batteries.
• The study offers a valuable reference for developing high-performance Zn-I₂ cells.