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Characterization of Electrode Materials for Lithium Ion and Sodium Ion Batteries Using Synchrotron Radiation Techniques
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Investigating Bubble Formation and Evolution in Vanadium Redox Flow Batteries via Synchrotron X-Ray Imaging
Kangjun Duan1, Kerstin Köble1, Alexey Ershov2
1Helmholtz Institute Ulm, Karlsruhe Institute of Technology, 89081, Ulm, Germany.
Chemsuschem
|April 9, 2025
Summary
Parasitic hydrogen evolution reaction in vanadium redox flow batteries (VRFBs) creates bubbles that reduce efficiency. This study reveals how these bubbles form, grow, and change shape within the battery electrodes.
Area of Science:
- Electrochemistry
- Materials Science
- Chemical Engineering
Background:
- Parasitic hydrogen evolution reaction (HER) in vanadium redox flow batteries (VRFBs) impedes electrolyte flow and reduces effective electrochemical surface area.
- This leads to significant efficiency losses in the negative half-cell of VRFBs.
Purpose of the Study:
- To investigate the formation and evolution of hydrogen bubbles within VRFB electrodes.
- To understand the impact of HER on bubble dynamics and electrode performance.
Main Methods:
- Synchrotron X-ray tomography was used for in-situ imaging of the VRFB electrode.
- A deep learning model combined with morphological analysis identified and characterized gas bubbles.
Main Results:
- HER intensity increases at more negative potentials, promoting bubble growth and fusion in the electrode's central region.
- Independent bubbles predominantly form at the electrode edges.
- Bubble growth results in gradually developing irregular shapes.
Conclusions:
- The study provides detailed insights into the rules governing hydrogen bubble formation and evolution in VRFB electrodes.
- Understanding these dynamics is crucial for improving VRFB efficiency and performance.
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