Wednesday, 21 March 2007 - 10:30 AM

Characterization Studies on Metallic Bipolar Plates and Membrane Electrode Assembly (MEA) for PEM Fuel Cells

Hazem Tawfik, Yue Hung, and Devinder Mahajan. Farmingdale State University of Ne w York

A surface characterization studies were performed on both the anode and cathode of a metal coated bipolar plate and the Membrane Electrode Assembly (MEA) after operating in a single cell under cyclic loading at normal conditions for 1000 hours with 70oC cell temperature; hydrogen RH = 70%; air RH = 95% and 10 psi pressure on both sides of reactant gases. The Scan Electron Microscope (SEM) study combined with EDAX analysis indicated the stability of the coating with no dissociation or dissolution in the main base of the metal alloy coating. The nickel chrome used in this alloy as a binding agent may have experienced a small or no appreciative decomposition of this metal compound. The research findings of this technique have agreed with the independent testing for metal residues that could have been washed out with water produced by the fuel cell as a byproduct. The mass spectroscopy technique was independently utilized to analyze samples of water collected from metallic bipolar plates PEM fuel cells operated under normal conditions. All metal concentrations were considerably less than one part per million (P.P.M). The X-ray diffraction testing on the MEA of both electrodes clearly showed a possible clustering of the catalyst after 1000 hours. Despite this clustering should have caused power decay as a result of the reduction in the active surface area that facilitates the electrochemical reaction inside the fuel cell; however, the lifetime testing did not show power decay resulting from corrosion, that could tarnish the catalyst and poison the ionomer, or catalyst clustering. This is an indication that the clustering mechanism was not very pronounced.

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