Quantum Size Effect Synergizes Space-Limited Domain Action for Advanced Aqueous Zinc-Iodine Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Rechargeable aqueous zinc-iodine batteries (AZIBs) offer high theoretical capacity and cost-effectiveness for grid-scale energy storage.
• Key challenges include the polyiodide shuttle effect and slow redox kinetics, hindering practical application.

Purpose of the Study:

• To design and synthesize an advanced iodine host material for AZIBs.
• To mitigate the polyiodide shuttle effect and accelerate redox kinetics for improved battery performance.

Main Methods:

• Synthesis of an Al-TCPP(Fe) metal-organic framework (MOF) as an iodine host.
• Utilizing the MOF's microporous structure for spatial confinement of polyiodides.
• Engineering Fe-N4 catalytic sites within the MOF to induce quantum size effects and enhance redox kinetics.

Main Results:

• The I2@Al-TCPP(Fe) cathode exhibited a high specific capacity (210.95 mAh g-1 at 1C).
• Achieved an exceptionally long cycling lifespan (>54,000 cycles at 50C).
• Demonstrated the feasibility of fabricating ampere-hour-level pouch cells.

Conclusions:

• The developed MOF effectively suppresses the shuttle effect through spatial confinement.
• Quantum size effects at Fe-N4 sites significantly boost iodine redox kinetics.
• This synergistic strategy offers a promising pathway for high-performance, long-lifespan AZIBs.