US 9,957,164 B2 · Highly conducting graphitic films from graphene liquid crystals

Abstract

A process for producing a highly oriented graphitic film, consisting of (a) preparing a dispersion having graphene oxide (GO) or chemically functionalized graphene (CFG) dispersed in a liquid to form a liquid crystal phase (but not in a GO gel state); (b) depositing the dispersion onto a supporting substrate to form a layer of GO or CFG under an orientation-inducing stress; (c) removing the liquid to form a dried GO or CFG layer having an inter-plane spacing d002 of 0.4 nm to 1.2 nm; (d) thermally reducing the dried layer at a first temperature higher than 100° C. to produce a porous layer of reduced GO or CFG; (e) further heat-treating the porous layer at a second temperature to produce a porous graphitic film having an inter-plane spacing d002 less than 0.4 nm; and (f) compressing the porous graphitic film to produce the highly oriented graphitic film.

Claims25

Dependent claims

A highly oriented graphitic film comprising a graphitic material, chemically functionalized graphitic material, or a combination thereof, wherein said film contains chemically bonded graphene planes that are parallel to one another and said film has a thickness from 100 nm to 0.1 mm, a physical density from 1.8 g/cm3 to 2.15 g/cm3, an inter-plane spacing d002 from 0.3354 nm to 0.4 nm, an oxygen content or non-carbon element content less than 1% by weight, and an electrical conductivity from 3,000 S/cm to 20,000 S/cm.

A process for producing a highly oriented graphitic film comprising a graphitic material and further comprising chemically functionalized graphitic material or graphene oxide, wherein said film contains chemically bonded graphene planes that are parallel to one another and said film has a thickness from 100 nm to 0.1 mm, a physical density from 1.8 g/cm3 to 2.15 g/cm3, an inter-plane spacing d002 from 0.3354 nm to 0.4 nm, an oxygen content or non-carbon element content less than 1% by weight, and an electrical conductivity from 3,000 S/cm to 20,000 S/cm, said process comprising:

a) preparing a dispersion of pristine graphene comprising pristine graphene sheets dispersed in a liquid medium, wherein said pristine graphene sheets are in an amount sufficient to form a pristine graphene liquid crystal phase in said liquid medium
b) adding graphene oxide sheets or chemically functionalized graphene sheets to said dispersion of pristine graphene, wherein said graphene oxide sheets or chemically functionalized graphene sheets comprise 0% to 20% by weight of the graphene sheets in said dispersion;
c) dispensing and depositing said dispersion onto a surface of a supporting substrate to form a layer of graphene material, wherein said dispensing and depositing procedure includes subjecting said liquid crystal phase to an orientation-inducing stress;
d) partially or completely removing said liquid medium from a layer of graphene material to form a dried a layer of graphene material having a layer thickness from 100 nm to 200 μm;
e) optionally compressing said a layer of graphene material to reduce a thickness of said material;
f) heat-treating said a layer of graphene material under optional compressive stress at a temperature from 1,500° C. to 3,250° C. for a sufficient period of time to produce a graphitic film having an inter-plane spacing d002 from 0.3354 nm to 0.37 nm;
and
g) optionally compressing said graphitic film to produce said highly oriented graphitic film.

5 more elements

Dependencies are inferred from the claim text.

Highly conducting graphitic films from graphene liquid crystals

Life of this patent

Highly conducting graphitic films from graphene liquid crystals

Life of this patent

Abstract

Claims25