Figure: Authors’ representation of oxygen permeability in anion exchange membranes.

Water: the gatekeeper for oxygen transport through anion exchange membranes used in fuel cells

The motivationGas transport is an important process in fuel cell technology that can limit the amount of electrical power a fuel cell can generate. SFU researchers are interested in determining how fast or slow dissolved oxygen gas travels through a novel alkali-based, ion transporting membrane that has been exclusively developed in their laboratory for the purpose of fabricating alkaline polymer fuel cells.

The discovery – The authors successfully demonstrated the use of microelectrodes to extract mass transport data of oxygen in polymer films.  They showed that oxygen travels up to 20 times slower through anion exchange membrane polymers when the relative humidity of the atmosphere is reduced.

Its significance – This is an important discovery because the use of microelectrodes to extract mass transport data of oxygen in polymer films represents a first for alkaline polymers; furthermore, the dramatic effect ambient humidity has on oxygen transport is surprising, with the implication that the surrounding humidity must be strongly considered or controlled to generate maximum power in alkaline fuel cells.  The work is important to researchers and developers in the field of anion exchange membrane fuel cell technology, and their applications in the automotive industry and power generation.  The methods presented in the paper can be used to screen for materials that can operate at lower relative humidity by improving the oxygen transport. This can result in cost savings and improved efficiencies in systems.

Read the paper“Electrochemical Reduction of Dissolved Oxygen in Alkaline, Solid Polymer Electrolyte Films” by David Novitski, Aslan Kosakian, Thomas Weissbach, Marc Secanell, and Steven Holdcroft. J. Am. Chem. Soc., 138(47):15465–15472 (2016). DOI: 10.1021/jacs.6b09217

Website article compiled by Jacqueline Watson with Theresa Kitos