COMPOSITE CATALYST LAYER, ELECTRODE AND PASSIVE MIXING FLOW FIELD FOR COMPRESSIONLESS FUEL CELLS

摘要

The application relates to improvements to the composition and architectureof compressionless fuel cells. The invention includes a hybrid or compositecatalyst layer which includes a blend of catalyst particles, such as platinumon carbon, and fibers, such as graphite fibers. The invention also relates toa castable gas diffusion layer (GDL) which is both porous and electricallyconductive. The GDL is formed from conductive metal flakes, such as goldand silver, carbon particles and binder to hold the flakes and particlestogether to form a porous foam microstructure. The invention furtherrelates to a modified flow field for flowing fluid to or from the catalystlayer of a fuel cell. The flow field comprises at least one primary channelhaving a longitudinal axis and a plurality of secondary channels extendingtransversely from the primary channel at an angle relative to the longitudi-nal axis. The secondary channels induce the fluid flow path to rotate tothereby passively increase the probability of contact and mixing betweenthe fluid and the catalyst layer. This in turn improves the delivery ofreactants to the catalyst layer and the removal of reaction products from thecatalyst layer. The catalyst layer, GDL and flow field may be synergisti-cally combined to improve the efficiency and performance ofcompressionless micro fuel cells.