The use of a novel water porosimeter to predict the water handling behaviour of gas diffusion media used in polymer electrolyte fuel cells

• Published in: Journal of power sources Vol. 193; no. 1; pp. 122 - 129
• Main Authors: Harkness, I.R., Hussain, N., Smith, L., Sharman, J.D.B.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.08.2009; Elsevier
• Subjects: Applied sciences; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Flooding; Fuel cells; Gas diffusion layer; PEMFC; Porosimetry; Two phase flow; PEMFC; Two phase flow; Gas diffusion layer; Flooding; Porosimetry; Mercury porosimetry; Gaseous diffusion; Polymer electrolytes; Wetting; Capillary pressure; Performance; Fuel cell
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2008.11.055

A novel water porosimeter and its use in determining the capillarity of gas diffusion layers are described. It is found that, in accordance with the Washburn equation, the pressure required to force water into the gas diffusion layer depends on the cosine of the contact angle of water with the surface of the pore. Negative pressure is required to withdraw water from the gas diffusion layer, even when the surface is hydrophobic. The negative pressure required is found to be independent of surface contact angle. It is shown that the performance of gas diffusion layers in an operating fuel cell can be qualitatively predicted from the capillary pressure curves obtained. The advantages of the use of water porosimetry over the use of either mercury porosimetry or porosimetry using wetting fluids are discussed.