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Alcohol Diffusion in Alkali-Metal-Doped Polymeric Membranes for Using in Alkaline Direct Alcohol Fuel Cells
Andrea Fernández-Nieto1, Sagrario Muñoz1, Vicenta María Barragán1
1Department of Structure of Matter, Thermal Physics and Electronics, Faculty of Physics, University Complutense of Madrid, 28040 Madrid, Spain.
Membranes
|July 25, 2022
Summary
Anion exchange membrane alcohol permeability is key for alkaline direct alcohol fuel cells. Doping conditions and membrane structure significantly impact alcohol crossover, affecting fuel cell performance.
Area of Science:
- Electrochemistry
- Materials Science
- Chemical Engineering
Background:
- Anion exchange membranes (AEMs) are critical components in alkaline direct alcohol fuel cells (ADAFCs) and electrolyzers, facilitating ion transport while hindering fuel crossover.
- The alcohol permeability of AEMs directly influences fuel cell efficiency and longevity by controlling fuel crossover.
Purpose of the Study:
- To compare the alcohol permeability of four commercial anion exchange membranes with varying structures.
- To investigate the effect of alkaline doping agents (LiOH, NaOH, KOH) and doping conditions on membrane behavior and alcohol permeability.
- To analyze the diffusive contribution to alcohol crossover for methanol, ethanol, and 1-propanol.
Main Methods:
- Analysis of alcohol permeability in hydro-organic media for four commercial AEMs.
- Membrane doping using LiOH, NaOH, and KOH under varied conditions.
- Determination of alcohol permeability for different membrane systems, focusing on diffusive crossover.
Main Results:
- Membrane alcohol permeability is significantly influenced by doping conditions, membrane type, and the nature of the alcohol.
- Heterogeneous membranes generally showed a positive correlation between alcohol permeability and doping capacity, with reduced permeability for larger alcohols.
- No consistent trend in alcohol permeability was observed for homogeneous membranes across different doping conditions.
Conclusions:
- Optimizing doping conditions and selecting appropriate AEMs are crucial for minimizing alcohol crossover in ADAFCs.
- Membrane structure plays a vital role in alcohol permeability, with heterogeneous membranes offering potentially better control over fuel crossover for larger alcohols.
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