Quantifying water transport in anion exchange membrane fuel cells

• Published in: International journal of hydrogen energy Vol. 44; no. 10; pp. 4930 - 4939
• Main Authors: Eriksson, Björn, Grimler, Henrik, Carlson, Annika, Ekström, Henrik, Wreland Lindström, Rakel, Lindbergh, Göran, Lagergren, Carina
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 22.02.2019
• Subjects: Anion exchange membrane fuel cell; Fuel cells; Relative humidity sensor; Water transport model; Anion exchange membrane fuel cell; Relative humidity sensor; Water transport model; Fuel cells
• ISSN: 0360-3199; 1879-3487; 1879-3487
• DOI: 10.1016/j.ijhydene.2018.12.185

Sufficient water transport through the membrane is necessary for a well-performing anion exchange membrane fuel cell (AEMFC). In this study, the water flux through a membrane electrode assembly (MEA), using a Tokuyama A201 membrane, is quantified using humidity sensors at the in- and outlet on both sides of the MEA. Experiments performed in humidified inert gas at both sides of the MEA or with liquid water at one side shows that the aggregation state of water has a large impact on the transport properties. The water fluxes are shown to be approximately three times larger for a membrane in contact with liquid water compared to vaporous. Further, the flux during fuel cell operation is investigated and shows that the transport rate of water in the membrane is affected by an applied current. The water vapor content increases on both the anode and cathode side of the AEMFC for all investigated current densities. Through modeling, an apparent water drag coefficient is determined to −0.64, indicating that the current-induced transport of water occurs in the opposite direction to the transport of hydroxide ions. These results implicate that flooding, on one or both electrodes, is a larger concern than dry-out in an AEMFC. [Display omitted] •Experimental determination of AEMFC transport coefficients in cells.•Partial pressure of water is the main driving force for diffusion.•Both anode and cathode increase in water content during operation.