In future energy concepts, polymer electrolyte membrane (PEM) cells and solid oxide cells play an important role. Such cells can by used for water splitting converting regenerative energy from wind or sun into hydrogen. Vice versa, such cells can be operated in the fuel cell mode generating electrical energy from controlled oxidation of pure hydrogen or reformates of hydrocarbon fuels. For both kinds of cells, porous metal tapes made by powder metallurgy can be implemented to improve the function of the cells. In the presentation, two examples are given explaining in more detail, which specific boundary conditions must be fulfilled to enable longterm stable operation of the cells when integrating such porous tapes.
a.) One of the cost drivers in PEM electrolysis cells is the porous current collector, which is usually made of titanium. Recently, tape casting of titanium powders was introduced for manufacturing of current collectors with improved microstructure and dimensions of up to 500 x 500 mm2. Gas atomized and hydrogenation-dehydrogenation (HDH) powders were used as starting materials. For both powders, slurry preparation, tape casting and sintering parameters were optimized separately aiming on the production of plane, undistorted tapes with well-defined thickness and porosity. Systematic electrochemical studies were conducted to point out the relationship between processing parameters, microstructure and electrochemical performance.
b.) Metal supported solid oxide fuel cells (MSCs) are attractive candidates for non-stationary fuel cell applications like auxiliary powers units (APUs) or range extender for battery electric vehicles due to their inherent mechanical robustness, improved sealing ability and potential of cost reduction. Introduction of a metal support requires complete adaption of the processing of all functional ceramic layers. Conventional sintering in air is not tolerable due to strong oxidation of the metal substrate. A specific processing concept for the functional layers is introduced, which enables protection of the metal substrate from oxidation while achieving high electrochemical performance.