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Updated: Jun 17, 2026
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Electrophoretic Crystallization of Ultrathin High-performance Metal-organic Framework Membranes
Published on: August 16, 2018
Pore size engineering in covalent organic frameworks for high-performance anion exchange membranes
Man Cai1, Hengyi Wang1, Tianyi Chen1
1Key Laboratory for Advanced Materials, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China. zhangbin@ecust.edu.cn.
Nanoscale
|June 16, 2026
Summary
Covalent organic framework (COF) anion exchange membranes (AEMs) offer improved stability and conductivity for water electrolysis and fuel cells. Optimizing COF pore size and side chain balance is key to enhancing ion transport.
Area of Science:
- Materials Science
- Electrochemistry
- Polymer Chemistry
Background:
- Anion exchange membranes (AEMs) are critical for hydrogen production and fuel cells, but face challenges with swelling and conductivity.
- Covalent organic frameworks (COFs) offer ordered structures for AEMs, improving swelling resistance and ionic conductivity.
Purpose of the Study:
- Investigate the impact of pore dimensions in COF-based AEMs on membrane performance.
- Synthesize and characterize COF membranes with varying framework sizes and identical flexible side chains.
Main Methods:
- Synthesis of COF membranes with tailored pore sizes.
- Incorporation of 1-methylpiperidine flexible side chains.
- Measurement of ion exchange capacity (IEC) and hydroxide ion (OH-) conductivity.
Main Results:
- COF-Pip-S2 achieved a record ion exchange capacity (IEC) of 4.0 mmol g⁻¹.
- COF-Pip-2 exhibited a hydroxide ion (OH-) conductivity of 207.1 mS cm⁻¹ at 80 °C.
- Ion transport is primarily governed by grafted side chain groups.
Conclusions:
- Framework pore dimensions significantly influence COF-based AEM performance.
- Optimizing the balance between hydrophilic side chains and hydrophobic frameworks is crucial for enhanced conductivity.
- This study provides insights into universal principles for designing high-performance AEMs.
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