Process for producing highly oriented graphene films

摘要

A process for producing a highly oriented graphene film (HOGF), comprising: (a) preparing a graphene oxide (GO) dispersion having GO sheets dispersed in a fluid medium; (b) dispensing and depositing the dispersion onto a surface of a supporting substrate to form a layer of GO, wherein the dispensing and depositing procedure includes subjecting the dispersion to an orientation-inducing stress; (c) removing the fluid medium to form a dried layer of GO having an inter-plane spacing d002 of 0.4 nm to 1.2 nm; (d) slicing the dried layer of GO into multiple pieces of dried GO and stacking at least two pieces of dried GO to form a mass of multiple pieces of GO; and (f) heat treating the mass under an optional first compressive stress to produce the HOGF at a first heat treatment temperature higher than 100° C. to an extent that an inter-plane spacing d002 is decreased to a value less than 0.4 nm.

主权项

1. A process for producing a highly oriented graphene film (HOGF) with a thickness no greater than 0.1 mm, said process comprising:
(a) preparing either a graphene oxide dispersion having graphene oxide sheets dispersed in a fluid medium or a graphene oxide gel having graphene oxide molecules dissolved in a fluid medium, wherein said graphene oxide sheets or graphene oxide molecules contain an oxygen content higher than 5% by weight; (b) dispensing and depositing said graphene oxide dispersion or graphene oxide gel onto a surface of a supporting substrate to form a first layer of graphene oxide, wherein said dispensing and depositing procedure includes subjecting said graphene oxide dispersion or graphene oxide gel to an orientation-inducing stress; (c) partially or completely removing said fluid medium from the first layer of graphene oxide to form a first dried layer of graphene oxide having a layer thickness less than 200 μm and having an inter-plane spacing d002 of 0.4 nm to 1.2 nm as determined by X-ray diffraction and an oxygen content no less than 5% by weight; (d) preparing at least a second dried layer of graphene oxide by repeating steps (b) and (c) at least one time or preparing multiple sheets of dried graphene oxide by slicing said first dried layer of graphene oxide; (e) stacking either said first dried layer of graphene oxide with said at least the second dried layer of graphene oxide or said multiple sheets of dried graphene oxide under an optional first compressive stress to form a mass of multiple layers of graphene oxide; and (f) heat treating the mass of multiple layers of graphene oxide under an optional second compressive stress to produce said highly oriented graphene film at a first heat treatment temperature higher than 100° C. to an extent that an inter-plane spacing d002 is decreased to a value less than 0.4 nm and the oxygen content is decreased to less than 5% by weight, wherein said step (f) occurs before, during, or after said step (e).