Highly conductive graphitic films
A flexible graphene platelet-filled composite film comprising a carbon or graphitic matrix and 1% to 99% weight fraction of graphene platelets dispersed in the matrix, wherein the graphene platelets are aligned along planar directions of said film and are selected from pristine graphene, oxidized graphene, reduced graphene oxide, fluorinated graphene, hydrogenated graphene, doped graphene, chemically functionalized graphene, or a combination thereof, and wherein the carbon or graphitic matrix is obtained by carbonizing a carbon precursor polymer at a carbonization temperature of at least 300° C. or by carbonizing and graphitizing the carbon precursor polymer at a final graphitization temperature higher than 1,500° C., and the graphitic matrix comprises graphene layers that are substantially oriented parallel to one another with an inclination angle between two graphene layers less than 5 degrees. The film is thermally and electrically conductive, and can be used to dissipate heat in an electronic device or device housing.
1. A graphene platelet-filled composite film comprising a carbon or graphitic matrix as a continuous phase and from 1% to 70% weight fraction of graphene platelets dispersed in said matrix, wherein said graphene platelets are aligned along planar directions of said film and are selected from pristine graphene, oxidized graphene, reduced graphene oxide, fluorinated graphene, hydrogenated graphene, doped graphene, chemically functionalized graphene, or a combination thereof, and wherein said carbon or graphitic matrix is obtained by carbonizing a carbon precursor polymer at a carbonization temperature of at least 300° C. or by carbonizing and graphitizing said carbon precursor polymer at a final graphitization temperature higher than 1,500° C., wherein said carbon precursor polymer is selected from the group consisting of polyimide, polyamide, polyoxadiazole, polybenzoxazole, polybenzobisoxazole, polythiazole, polybenzothiazole, polybenzobisthiazole, poly(p-phenylene vinylene), polybenzimidazole, polybenzobisimidazole, and combinations thereof; and said carbon or graphitic matrix comprises graphene layers, derived from said carbon precursor polymer, that are substantially oriented parallel to one another with an inclination angle between two graphene layers less than 5 degrees.
2. The graphene platelet-filled composite film of claim 1 , wherein the graphene platelets comprise a single-layer graphene sheet or a multi-layer graphene platelet with a thickness less than 10 nm.
3. The graphene platelet-filled composite film of claim 1 , wherein the graphene platelets comprise a multi-layer graphene platelet with a thickness less than 4 nm.
4. The graphene platelet-filled composite film of claim 1 , wherein the graphene platelets comprise a single-layer pristine graphene sheet or a multi-layer pristine graphene platelet with a thickness less than 10 nm and said pristine graphene sheet or pristine graphene platelet contains no oxygen and is produced from a process that does not involve oxidation.
5. The graphene platelet-filled composite film of claim 1 , wherein the graphene platelet-filled composite film has an inter-graphene spacing less than 0.338 nm, a thermal conductivity of at least 1,000 W/mK, and/or an electrical conductivity no less than 5,000 S/cm.
6. The graphene platelet-filled composite film of claim 1 , wherein the graphene platelet-filled composite film has an inter-graphene spacing less than 0.337 nm, a thermal conductivity of at least 1,200 W/mK, an electrical conductivity no less than 7,000 S/cm, a physical density greater than 1.9 g/cm3, and/or a tensile strength greater than 30 MPa.
7. The graphene platelet-filled composite film of claim 1 , wherein the graphene platelet-filled composite film has an inter-graphene spacing less than 0.336 nm, a thermal conductivity of at least 1,500 W/mK, an electrical conductivity no less than 10,000 S/cm, a physical density greater than 2.0 g/cm3, and/or a tensile strength greater than 35 MPa.
8. The graphene platelet-filled composite film of claim 1 , wherein the graphene platelet-filled composite film exhibits an inter-graphene spacing less than 0.337 nm and a mosaic spread value less than 1.0.
9. The graphene platelet-filled composite film of claim 1 , wherein the graphene platelet-filled composite film exhibits a degree of graphitization no less than 60% and/or a mosaic spread value less than 0.7.
10. The graphene platelet-filled composite film of claim 1 , wherein the graphene platelet-filled composite film exhibits a degree of graphitization no less than 90% and/or a mosaic spread value less than 0.4.
11. The graphene platelet-filled composite film of claim 1 , further comprising a filler selected from natural graphite, expanded graphite, artificial graphite, meso-phase carbon, meso-phase pitch, meso-carbon micro-bead, soft carbon, hard carbon, coke, carbon fiber, carbon nano-fiber, carbon nano-tube, or a combination thereof.
12. An electronic device containing the graphitic film of claim 1 as a heat-dissipating element therein.