Modulating Lewis Acidity of Covalent Organic Frameworks to Boost Li+ Transport
Wenwei Li1, Cuiping Luo1, Fanyu Xie1
1National Center for International Joint Research of Photoelectric Energy Materials and Application, International Joint Research Center for Advanced Energy Materials of Yunnan Province, School of Materials and Energy, Yunnan University, Kunming, China.
Angewandte Chemie (International Ed. in English)
|August 5, 2026
Summary
Researchers improved solid polymer electrolytes for safer lithium metal batteries by tuning Lewis acidity to enhance ion transport and stability. This molecular design strategy boosts conductivity and battery performance.
Area of Science:
- Materials Science
- Electrochemistry
- Polymer Chemistry
Background:
- Solid polymer electrolytes (SPEs) are key for safer lithium metal batteries.
- Poor Li+
- -TFSI- coupling and low salt dissociation limit room-temperature conductivity in SPEs.
- Lewis acidic sites can improve Li+ release but their effect on ion transport is unclear.
Purpose of the Study:
- To investigate the impact of local Lewis acid-base regulation on ion transport in SPEs.
- To design and synthesize novel ionic covalent organic frameworks (ICOFs) for enhanced SPE performance.
- To establish a molecular design strategy for SPEs with high ionic conductivity and interfacial stability.
Main Methods:
- Synthesized olefin-linked pyridinium ICOFs with varying counteranions (Br-, BF4-, PF6-, TFSI-).
- Incorporated ICOFs into a PVDF-HFP matrix to form composite SPEs.
- Characterized SPEs using electrochemical methods (conductivity, transference number), spectroscopy (Raman), molecular dynamics, and operando techniques.
Main Results:
- Weakly coordinating counteranions enhanced ICOF Lewis acidity and weakened Li+-TFSI- coupling.
- ICOF-TFSI@PVDF-HFP achieved high ionic conductivity (9.1 × 10-4 S·cm-1) and Li+ transference number (0.81).
- Demonstrated stable Li||Li cycling (>6500 h) and excellent capacity retention in Li||LFP and Li||NCM90 cells.
Conclusions:
- Local Lewis acid-base regulation is a viable strategy for designing high-performance SPEs.
- Enhanced salt dissociation, regulated interfacial chemistry, and dendrite suppression contribute to improved battery performance.
- The developed ICOF-based SPEs offer a promising pathway for safer and more efficient lithium metal batteries.
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