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Published on: February 13, 2017
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Engineered Microdefects in Nano-Membranes for Enhanced Ion Selectivity and Membrane Durability in Vanadium Redox Flow
Jongmin Q Kim1,2, Yoonki Lee3,4, Jiwoo Lee3,4
1Interface Materials and Chemical Engineering Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon, 34114, South Korea.
Small (Weinheim an Der Bergstrasse, Germany)
|June 13, 2025
Summary
Researchers developed ultrathin perfluorinated sulfonic acid (PFSA) membranes for vanadium redox flow batteries (VRFBs). These membranes improve ion selectivity and battery performance by using engineered microdefects as pores, overcoming limitations of conventional dense membranes.
Area of Science:
- Materials Science
- Electrochemistry
- Energy Storage
Background:
- Conventional perfluorinated sulfonic acid (PFSA) membranes in vanadium redox flow batteries (VRFBs) face limitations due to dense structures hindering proton transport and causing operational deformation.
- Enhancing proton/vanadium ion selectivity is crucial for improving VRFB performance and overcoming current membrane drawbacks.
Purpose of the Study:
- To demonstrate sub-25 nm ultrathin PFSA membranes with engineered microdefects for improved proton transport and structural integrity in VRFBs.
- To overcome the trade-off between proton conductivity and ion selectivity in conventional VRFB membranes.
Main Methods:
- Fabrication of ultrathin PFSA membranes by stacking 14 molecularly thin PFSA Langmuir monolayers with controlled packing density.
- Establishment of proton-conducting pathways through pre-swelling.
- Characterization of membrane morphology, ion selectivity, and electrochemical performance under operational conditions.
Main Results:
- Demonstrated sub-25 nm ultrathin PFSA membranes with engineered microdefects acting as size-exclusive pores.
- Achieved higher ion selectivity compared to commercial Nafion 211 membranes.
- The optimized membrane exhibited superior cyclic and rate performance, delivering ≈76% energy efficiency and long-term stability at 200 mA cm⁻² without capacity decay.
Conclusions:
- Engineered microdefects in ultrathin PFSA membranes effectively promote proton transport while maintaining structural integrity.
- This approach offers a promising strategy to overcome the limitations of conventional dense membranes in VRFBs.
- The developed ultrathin membranes show significant potential for enhancing the efficiency and durability of vanadium redox flow batteries.
