Microporous layer for water morphology control in PEMFC

• Published in: International journal of heat and mass transfer 2009-05, Vol.52 (11), p.2779-2791
• Main Authors: Nam, Jin Hyun, Lee, Kyu-Jin, Hwang, Gi-Suk, Kim, Charn-Jung, Kaviany, Massoud
• Format: Article
• Language: English
• Subjects: Applied sciences; Catalyst effectiveness; Catalyst layer (CL); Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Gas diffusion layer (GDL); Liquid saturation distribution; Microporous layer (MPL); Polymer electrolyte membrane fuel cell (PEMFC); Water management
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2009.01.002

We have used environmental scanning electron microscope to observe vapor condensation and liquid water morphology and breakthrough in porous layers of polymer electrolyte membrane fuel cell. These suggest presence of large droplets and high liquid saturation at interface of the catalyst layer (CL) and gas diffusion layer (GDL), due to jump in pore size. We develop a model for morphology of liquid phase across multiple porous layers by use of both continuum and breakthrough (percolation) treatments. Using the results of this model we show the liquid morphologies deteriorate the efficiency of electrochemical reactions in CL and increase the water saturation in GDL. Then we show that inserting a microporous layer between CL and GDL reduces both the droplet size and liquid saturation and improves the cell performance.