Hydrophobicity Patterning of Gas Diffusion Media for Polymer Electrolyte Fuel Cells

Kurzfassung

Polymer electrolyte fuel cells with their high gravimetric energy density face a water balance problem especially under variable loads, e.g. in automotive conditions: The excess product water needs to be removed from the fuel cell while maintaining a humidifed membrane. The gas diffusion layer, which also provides contact to the electro- chemically active components, has to achieve the passive management of the water balance. Heterogeneously hydrophobic gas diffusion media have already shown to be more capable of balancing these opposing requirements than conventional materials. Various methods of pattern- ing gradients of hydrophobicity are applied, like microperforation and laser, focused X-Ray and ion beam irradiation. The modifcations are analysed with photoemission and infrared spectroscopy and compared for their performance, applicability and scalability. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) for Fuel Cell and Hydrogen Joint Technology Initiative under Grant No. 303446 (Impala).