title: X-ray tomography of morphological changes after freeze/thaw in gas diffusion layers.
abstract: Liquid water produced in a polymer electrolyte membrane fuel cell experiences a freeze/thaw cycle when the cell is switched off and on while operating at ambient temperatures below freezing. This freeze/thaw cycle permanently deforms the polymer electrolyte membrane fuel cell capillary structures and reduces both the cell life and its ability to generate electric power. The X-ray tomography facility at the Pohang Accelerator Laboratory was used to observe the freeze/thaw effects on the gas diffusion layer (GDL), which is the thickest capillary layer in the cell. Morphological changes in the GDL under a water freeze/thaw cycle were observed. A scenario in which freeze/thaw cycles affect fuel cell performance is suggested based on images from X-ray tomography.
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology, Namgu, Pohang, Kyoungbuk, South Korea.
authors.forename: Junho
authors.initials: J
authors.lastname: Je
authors.forename: Jongrok
authors.initials: J
authors.lastname: Kim
authors.forename: Massoud
authors.initials: M
authors.lastname: Kaviany
authors.forename: Sang Young
authors.initials: SY
authors.lastname: Son
authors.forename: MooHwan
authors.initials: M
authors.lastname: Kim