Fluorination-Decoupling MOFs for Enhanced Solvation Dynamics and Interface Stability in Lithium Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid-state lithium metal batteries face persistent interfacial instability.
• Developing electrolytes that control bulk transport and interfacial reactions is crucial.

Purpose of the Study:

• To introduce a fluorination-decoupling strategy for quasi-solid-state electrolytes.
• To tailor Li+ solvation dynamics and interfacial protection using fluorinated MOFs.

Main Methods:

• Integrating fluorinated MOFs with Lewis-acidic sites into PVDF-HFP electrolytes.
• Investigating the effects of fluorinated moieties on MOF Lewis acidity and Li+ coordination.
• Analyzing the composition of the solid electrolyte interphase (SEI).

Main Results:

• Fluorinated MOFs enhanced Lewis acidity, limited anion mobility, and weakened Li+ coordination.
• A stable SEI rich in LiF formed without compromising bulk conductivity (1.16 × 10-3 S cm-1).
• Exceptional cycling stability was achieved in Li||Li, Li||LiFePO4, and Li||NCM811 cells.

Conclusions:

• Precise control of fluorine-framework interactions offers a new route to tailor Li+ solvation.
• This strategy significantly improves interfacial stability in solid-state electrolytes for advanced lithium metal batteries.