Fabrication of catalytic electrodes for molten carbonate fuel cells
AssigneeThe United States of America as represented by the United States Department of Energy
InventorJames L. Smith
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Abstract
A porous layer of catalyst material suitable for use as an electrode in a molten carbonate fuel cell includes elongated pores substantially extending across the layer thickness. The catalyst layer is prepared by depositing particulate catalyst material into polymeric flocking on a substrate surface by a procedure such as tape casting. The loaded substrate is heated in a series of steps with rising temperatures to set the tape, thermally decompose the substrate with flocking and sinter bond the catalyst particles into a porous catalytic layer with elongated pores across its thickness. Employed as an electrode, the elongated pores provide distribution of reactant gas into contact with catalyst particles wetted by molten electrolyte.
Claims13
A method of forming a porous catalytic layer having elongated pores in general alignment along the thickness thereof for use as an electrode in a molten carbonate fuel cell comprising:
- providing a substrate of heat consumable material with flocking on an exposed surface thereof, said flocking comprising, fibers of about 5-20 microns diameter, 0.2-5 millimeters length and at a distribution of about 5,000-50,000 per cm.sup.2 aligned generally normal to the substrate surface;
- depositing particulate catalyst of no more than 100 microns particle size into the flocking on the substrate;
- heating the substrate with catalyst to consume the flocking a sintering, thereby leaving a porous catalytic layer with elongated pores in general alignment along the thickness thereof.
A method for forming an electrode for use in a molten carbonate fuel cell comprising;
- horizontally positioning a heat-consumable substrate having fiberous flocking on the upper surface thereof, the fibers being in general vertical alignment;
- preparing a slip of particulate catalyst in carrier liquid;
- casting the slip as a tape into the substrate flocking;
- heating the substrate with cast tape to a first temperature to set the tape, to a second temperature to consume the substrate and flocking and to a third temperature to sinter bond the particulate catalyst into a porous catalytic layer having elongated pores in general alignment along the layer thickness and having fine, random distributed pores among the catalytic particles.
Dependencies are inferred from the claim text.