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

During high current density operation, water produced in the cathode catalyst layer of a PEM fuel cell negatively impacts performance by lowering mass transport of oxygen into the cathode. 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.