Breakthrough in Rechargeable Aqueous Zinc-Iodine Batteries

Strategic Insights -

Researchers at the University of Science and Technology of China have made a significant advancement in rechargeable aqueous zinc-iodine batteries (ZIBs), addressing two major challenges: soluble polyiodide shuttling and rampant Zn dendrite growth. The team developed a polyampholyte bacterial cellulose hydrogel electrolyte (SBC) that overcomes these limitations, enabling the creation of highly stable and long-lasting batteries.

Key Takeaways:

  • The SBC electrolyte suppresses polyiodide shuttling and boosts redox kinetics of iodine species on the cathode side.
  • On the anode side, sulfonate anions enable a high Zn transference number (0.82) and guide epitaxial Zn nucleation.
  • Optimized Zn solvation and a restructured H-bond network lower desolvation barriers, inhibit corrosion, and minimize parasitic reactions.
  • The interconnected bacterial cellulose network provides robust ion channels while restricting iodine dissolution.
  • Zn||Zn symmetric cells with SBC electrolyte achieve exceptional stability (1800 h at 10 mA cm^-2 /10 mAh cm^2; 2500 h at 5 mA cm^-2 /5 mAh cm^2).
  • Zn-I full cells retain capacity over 20,000 cycles at 8 C with a minimal fade rate of 0.006% per cycle.

Statistics:

  • 1800 hours: the stability of Zn||Zn symmetric cells with SBC electrolyte at 10 mA cm^-2 /10 mAh cm^2.
  • 2500 hours: the stability of Zn||Zn symmetric cells with SBC electrolyte at 5 mA cm^-2 /5 mAh cm^2.
  • 20,000 cycles: the number of cycles Zn-I full cells were tested for.
  • 0.006% per cycle: the fade rate of Zn-I full cells.

Sources:

  • Conquering Shuttle Effect and Dendrites Synergistically: A Zwitterionic Bacterial Cellulose Hydrogel Electrolyte for Ultralong-Lifespan Zn-I2 Batteries. Small, 2025.
  • University of Science and Technology of China, Key Laboratory of Precision and Intelligent Chemistry, Dept. of Materials Science and Engineering.
  • Small, onlinelibrary.wiley.com/journal/10.1002/(ISSN)1613-6829
  • Yiran Zhu, Junkang Xu, Qinghua Gui, Panfeng Zhao, Lei Mao, and Tianzhi Luo.