Fabrication of dual porosity electrode structure
AssigneeThe United States of America as represented by the United States Department of Energy
InventorsJames L. Smith, Eugenia H. Kucera
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Abstract
A substantially entirely fibrous ceramic which may have dual porosity of both micro and macro pores. Total porosity may be 60-75% by volume. A method of spraying a slurry perpendicularly to an ambient stream of air is disclosed along with a method of removing binders without altering the fiber morphology. Adding fine ceramic particulates to the green ceramic fibers enhances the sintering characteristics of the fibers.
Claims29
An electrode for a molten carbonate fuel cell, comprising a substantially fibrous, dual porosity structure of randomly positioned electrode-active ceramic fibers.
An electrode for a molten carbonate fuel cell, comprising a dual porosity structure of randomly positioned electrode-active ceramic fibers, further comprising ceramic fine particles sintered to said ceramic fibers.
A method of forming ceramic fibers comprising:
- providing a slurry of fine ceramic particles and liquid carrier including a binder material and solvent, forming ceramic fibers from the slurry by spraying the slurry into a moving stream of gas, and treating the ceramic fibers formed from the slurry to remove the carrier.
A method of forming a thin porous sheet of ceramic material comprising:
- providing a slurry of fine ceramic particles and liquid carrier including a binder material, forming ceramic fibers from the slurry, calcining the ceramic fibers formed from the slurry at a sufficient temperature to drive off the binder, modifying the length of the ceramic fibers to a predetermined range, forming a slip of the ceramic fibers of modified length in a liquid carrier including a binder material and additional fine ceramic particles, spreading a thin layer of the slip onto a substrate, and heating the slip to sintering temperatures to form a porous sheet of ceramic material.
A fuel cell comprising a fuel electrode and an oxidant electrode and an electrolyte disposed between the electrodes, said oxidant electrode comprising randomly positioned ceramic fibers of a cathode-active material and fine ceramic particles sintered to said ceramic fibers, said oxidant electrode having dual porosity of micropores less than 5 microns and macropores greater than 10 microns, said electrolyte containing an alkali metal carbonate and particles distributed therethrough having sizes to ensure flooding of the micropores of the oxidant electrode with the electrolyte.
A ceramic material wherein more than 50 percent by weight of the ceramic is present as fibers having a porosity of 60%-75% by volume.
Dependencies are inferred from the claim text.