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Method of producing exfoliated graphite composite compositions for fuel cell flow field plates

United States Patent

April 8, 2014
View the Complete Patent at the US Patent & Trademark Office
A method of producing an electrically conductive composite composition, which is particularly useful for fuel cell bipolar plate applications. The method comprises: (a) providing a supply of expandable graphite powder; (b) providing a supply of a non-expandable powder component comprising a binder or matrix material; (c) blending the expandable graphite with the non-expandable powder component to form a powder mixture wherein the non-expandable powder component is in the amount of between 3% and 60% by weight based on the total weight of the powder mixture; (d) exposing the powder mixture to a temperature sufficient for exfoliating the expandable graphite to obtain a compressible mixture comprising expanded graphite worms and the non-expandable component; (e) compressing the compressible mixture at a pressure within the range of from about 5 psi to about 50,000 psi in predetermined directions into predetermined forms of cohered graphite composite compact; and (f) treating the so-formed cohered graphite composite to activate the binder or matrix material thereby promoting adhesion within the compact to produce the desired composite composition. Preferably, the non-expandable powder component further comprises an isotropy-promoting agent such as non-expandable graphite particles. Further preferably, step (e) comprises compressing the mixture in at least two directions. The method leads to composite plates with exceptionally high thickness-direction electrical conductivity.
Zhamu; Aruna (Centerville, OH), Shi; Jinjun (Columbus, OH), Guo; Jiusheng (Centerville, OH), Jang; Bor Z. (Centerville, OH)
Nanotek Instruments, Inc. (Dayton, OH)
11/ 800,730
May 8, 2007
This invention is based on the research results of a project supported by the US Department of Energy (DOE) SBIR-STTR Program. The US government has certain rights on this invention.