Effect of gas diffusion layer properties on water distribution across air-cooled, open-cathode polymer electrolyte fuel cells: A combined ex-situ X-ray tomography and in-operando neutron imaging study. (1st September 2016)

• Record Type: Journal Article
• Authors: Meyer, Quentin; Ashton, Sean; Boillat, Pierre; Cochet, Magali; Engebretsen, Erik; Finegan, Donal P.; Lu, Xuekun; Bailey, Josh J.; Mansor, Noramalina; Abdulaziz, Rema; Taiwo, Oluwadamilola O.; Jervis, Rhodri; Torija, Sergio; Benson, Paul; Foster, Simon; Adcock, Paul; Shearing, Paul R.; Brett, Dan J.L.
• Is Part Of: Electrochimica acta. Volume 211(2016)
• Page Start: 478
• Page End: 487
• Publication Date: 2016-09-01
• Subjects: Gas diffusion layer -- air-cooled open-cathode -- X-ray computed tomography -- neutron imaging -- water management; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.06.068
• Languages: English
• ISSNs: 0013-4686

Abstract

Graphical abstract: Highlights: First description of water distribution using in-plane neutron imaging in an air‐cooled, open-cathode fuel cell. High water content identified under cathode land area, whereas anode water content is relatively homogeneous. Water distribution in anode GDL directly linked to dispersion of PTFE. Anode GDL composition shown to affect water content and distribution in cathode. Combined X-ray computed tomography, SEM/EDS and TGA used to characterise GDL structure and composition. Abstract: In-operando diagnostic techniques provide a means of understanding the internal workings of fuel cells under normal operating conditions so that improved designs and operating regimes can be identified. Here, an approach is used which combines ex‐situ characterisation of two anode gas diffusion/microporous layers (GDL-A and GDL-B) with X-ray computed tomography (CT) and in-operando analysis using neutron imaging of operating fuel cells. The combination of TGA, SEM and X-ray CT reveals that GDL-A has a thin microporous layer with ∼26% PTFE covering a thick diffusion layer composed of 'spaghetti'-shaped fibres. GDL-B is covered by two microporous media (29% and 6.6% PTFE) penetrating deep within the linear fibre network. The neutron imaging reveals two pathways for water transport underneath the cooling channel, either diffusing through the cathode GDL to the active channels, or diffusing through the membrane and towards the anode. The behaviour of water in the GDL is directly affected by the anode gas diffusion, PTFE content and porosity.