(220e) Exploring Ionomer-Related Transport Phenomena in Polymer-Electrolyte Fuel Cells
Thus, we will explore the gas transport limitations within PEFC catalyst layers, with a focus on the observed local transport resistance as measured using hydrogen and oxygen limiting current measurements. We will examine test cases for diagnosis of polarization curves in terms of different limiting phenomena. Different oxygen concentrations, catalyst-layer properties, and operating humidity and temperature will be introduced.
Water management is a more serious concern in hydroxide PEFCs, because OH- conductivity is more highly dependent on water content and the oxygen-reduction reaction consumes water. Compared to proton PEFCs, the lower performance of hydroxide PEFCs is mostly caused by a extremely nonuniform distribution of water in the ionomer phase between the anode and cathode as well as the increased overpotential for the hydrogen oxidation reaction. In this presentation, we will discuss the performance-limiting mechanisms specific to different operating conditions (e.g. varying inlet relative humidity (RH)) based on a cell-level mathematical model. In addition, the issue of carbonate formation with the membrane will be discussed.
We would like to thank helpful discussions and samples from Toyota Motor Company. This work was mainly funded under the Fuel Cell Performance and Durability Consortium (FC PAD) funded by the Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, of the U. S. Department of Energy, Program Development Manager Dimitrios Papageorgopoulos