Catalyst support material for fuel cell
View Patent ↗A catalyst support material useful in a membrane electrode assembly is presented. The support catalyst material is elongate electrically anisotropic particles of flexible graphite, and the membrane electrode assembly includes a pair of electrodes, an ion exchange membrane having opposed surfaces positioned between the electrodes and a catalyst material on the inventive support, at least a portion of an opposed surface of the ion exchange membrane being adjacent the catalyst which is supported on the elongate electrically anisotropic particles of flexible graphite sheet.
1. A method for preparing a catalyst-loaded catalyst support material, which comprises:
(a) compacting expanded graphite particles under a load to form an anisotropic, oriented sheet or pad having a thickness of no more than about 25 mm;
(b) forming at least one individual, elongate electrically anisotropic particle of expanded graphite by milling the sheet or pad, wherein the at least one particle of expanded graphite is from about 2 to about 50 microns in length; and
(c) loading a catalyst material on the particle.
2. The method of claim 1 , wherein the catalyst material comprises a platinum group metal.
3. The method of claim 1 , wherein the at least one particle of expanded graphite has electrical resistivity along its length lower than the electrical resistivity transverse to its length.