Improved Cathode Catalyst Layers for Proton Exchange Membrane Fuel Cells

In this work we show how two different catalyst layer fabrication techniques can improve the PEM fuel cell performance by introducing macro porosities in the layer. In the first technique, a template with 4 μm diameter pillars made using photo lithography is pressed against the cathode side of Gore® Primea® MEA to create evenly distributed macro pores/channels. In the other technique, mono-dispersed polystyrene particles with 1 μm diameter were used as pore formers to obtain homogeneously distributed macropores in the cathode catalyst layer. These MEAs were made in-house with the cathode catalyst layer thicknesses of about 1 μm. Fuel cell testing carried out on these two types of modified MEA structures with lower Pt utilization show a reasonable improvement in the cell performance at higher current densities. The improved performance at high current densities could be attributed to the presence of macro porosities in the catalyst layer, which enhance the mass transport properties of the catalyst layer.