Tetraphenylethylene-Functionalized Zirconium Metal-Organic Frameworks Enabling Polyiodide Confinement for...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Tunable morphology and structure of metal-organic frameworks (MOFs) are crucial for optimizing their physical-chemical properties and electrochemical performance.
• Zirconium-based MOFs (Zr-MOFs) offer potential for advanced energy storage applications due to their stability and tunable porosity.

Purpose of the Study:

• To design and synthesize novel Zr-MOFs with enhanced structural features for improved electrochemical functionality.
• To investigate the use of these engineered Zr-MOFs as cathode hosts in aqueous zinc-iodine batteries.
• To elucidate the mechanisms governing charge-discharge processes and iodine stabilization within the MOF structure.

Main Methods:

• Employed a ligand extension strategy and controlled etching process for Zr-MOF synthesis.
• Utilized tetraphenylethylene-based ligands to create π-conjugated frameworks.
• Characterized MOF structure and performance using in situ Raman spectroscopy and theoretical analyses.

Main Results:

• Synthesized Zr-MOFs with increased active site exposure and improved π-conjugated transport channels.
• Achieved excellent iodine adsorption capacity and effective confinement of polyiodides.
• Demonstrated high capacitance, excellent cycling stability, and reversible iodine redox kinetics in M4/I₂ cathodes.

Conclusions:

• The developed Zr-MOFs provide a generalizable strategy for constructing MOFs with controlled morphology and structure.
• The combination of physical confinement and chemical absorbance effectively stabilizes iodine species, enhancing battery performance.
• These findings offer new insights for designing high-performance aqueous battery systems.