Controlling the Polymer/Gas Interfacial Property of the Ionic Polymer Phase of a PEM Fuel Cell Catalyst Layer during Membrane Electrode Assembly Fabrication

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Water management in a PEM fuel cell is vital during high current density operation. Water production in the cathode catalyst layer can negatively impact performance by lowering mass transport of oxygen into the cathode. Various advances have been developed to overcome water management issues related to PEMFCs. A few of these discoveries include the development of the interdigitated flow field [1], integration of hydrophobic PTFE nanoparticles into the catalyst layer [2, 3], and gas diffusion layer fabrication from various types of non-wetting materials [4, 5]. Each of these advances led to improved mass transport performance during high current density operations. In this presentation, a novel heat treatment process for controlling the ionic polymer phase surface properties in the fuel cell catalyst layer is incorporated into the fabrication process of the membrane electrode assembly (MEA). XPS is used to characterize the catalyst layer ionomer-gas interface in order to verify specific heat treatment conditions lead to a hydrophobic or hydrophilic ionomer surface. The MEA fabrication procedure is modified to ensure the catalyst layer is subjected to suitable heat treatment exposure conditions in order to create a hydrophobic ionomer-gas interface inside the cathode catalyst layer. Fuel cell performance results will be presented using the new MEAs under different operating temperatures, flow field types, and air humidification conditions. Acknowledgement The work presented was partially funded by the National Science Foundation under Grant No. EFRI-1038234 and CBET-1518755. References T.V. Nguyen, J. Electrochem. Soc., 143, L103 (1996).R. Friedmann and T.V. Nguyen, J. Electrochem. Soc., 157, B260 (2010).M. Uchida, Y. Aoyama, N. Eda and A. Ohta, J. Electrochem. Soc., 142, 4143 (1995).J. Benziger, J. Nehlsen, D. Blackwell, T. Brennan and J. Itescu, J. Membrane Science, 261, 98 (2005).T.V. Nguyen, A. Ahosseini, X. Wang, V. Yarlagadda, A. Kwong, A.Z. Weber, P. Deevanhxay, S. Tsushima and S. Hirai, J. Electrochem. Soc., 162, F1451 (2015).