Mass Transport in Gas Diffusion Layers in Polymer Electrolyte Fuel Cell

Abstract: Fuel cells constitute a promising future for energy conversion. The Polymer Electrolyte Membrane Fuel Cell (PEMFC) generates electricity using hydrogen and oxygen as fuel, reactants forming only water. It thus constitutes a zero-emission power source. It can be used in a wide variety of appliances, from consumer electronics to propulsion of vehicles. As further increase in performance is needed for PEMFC to be fully commercialised, operation at higher current densities than currently possible is needed. This development calls for improved water handling in the fuel cell as flooding of the Gas Diffusion Layer (GDL), especially at the cathode, might be a limitation for cell performance. This work is done in cooperation with Cellkraft AB, under the EU-supported PEMTOOL project. Results will be used as validation data for the next generation of modelling tools in the area of research. The purpose of this work is to study mass transport related problems, such as flooding, in GDL in PEMFC and to produce validation data to the PEMTOOL project. This is done by measuring cell performance under influence of varying cell temperature, gas pressure, oxygen partial pressure and humidification of reactant gases. This report explains the function of PEMFC, the design of the specific cell used in experiments and describes how experiments are executed. Results of this work indicate a connection between flooding of the cathode and lowered oxygen partial pressure in cathode gas, while operating the cell with oversaturated reactant gases. This highlights humidification optimisation as a key factor for further increase in PEMFC performance.