Patent ID: 8691129

Claim:
A method of producing an electrically conductive composite composition, said method comprising: a) providing a supply of expandable graphite powder; b) providing a supply of a non-expandable powder isotropy-promoting agent that enhances isotropy and reduces anisotropy and a binder or matrix, the binder or matrix being a powder and being present in an amount between 3 and 60% by weight; c) blending said expandable graphite with said non-expandable powder component to form a powder mixture wherein said 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 said powder mixture to a temperature sufficient for exfoliating the expandable graphite to obtain a compressible mixture comprising expanded graphite worms and said non-expandable component; e) without activating the binder or matrix material, compressing said compressible mixture at a pressure within the range of from about 5 psi to about 50,000 psi in a uniaxial, biaxial, triaxial or isostatic compression into predetermined forms of cohered graphite composite compact such that the isotropy promoting agent changes the orientation of the expandable graphite to a more isotropic orientation upon compression; and f) treating the so-formed cohered graphite composite to activate the binder or matrix material thereby promoting adhesion within the compact; wherein the method produces a composite compact having a thickness direction conductivity greater than 50 S/cm, the thickness direction conductivity also being greater than the thickness-direction conductivity when the isotropy promoting agent is not present, and having an in-plane conductivity of the composite compact that is less than the in-plane conductivity of the composite compact when the isotropy promoting agent is not present.