Process for Unitary Graphene Layer or Graphene Single Crystal

摘要

A unitary graphene layer or graphene single crystal containing closely packed and chemically bonded parallel graphene planes having an inter-graphene plane spacing of 0.335 to 0.40 nm and an oxygen content of 0.01% to 10% by weight, which unitary graphene layer or graphene single crystal is obtained from heat-treating a graphene oxide gel at a temperature higher than 100° C., wherein the average mis-orientation angle between two graphene planes is less than 10 degrees, more typically less than 5 degrees. The molecules in the graphene oxide gel, upon drying and heat-treating, are chemically interconnected and integrated into a unitary graphene entity containing no discrete graphite flake or graphene platelet. This graphene monolith exhibits a combination of exceptional thermal conductivity, electrical conductivity, mechanical strength, surface smoothness, surface hardness, and scratch resistance unmatched by any thin-film material of comparable thickness range.

主权项

1. A process for producing a unitary graphene layer or graphene single crystal containing closely packed and chemically bonded parallel graphene oxide planes having an inter plane spacing of 0.335 to 0.40 nm, a thickness greater than 10 nm, an electrical conductivity greater than 1,500 S/cm, a thermal conductivity greater than 600 W/mK, a physical density greater than 1.8 g/cm3, an oxygen content of 0.01% to 10% by weight, and an average mis-orientation angle between two graphene oxide planes is less than 10 degrees, said process comprising:
a. preparing a graphene oxide gel having graphene oxide molecules dispersed in a fluid medium, wherein the graphene oxide gel is optically transparent or translucent; b. depositing a layer of said graphene oxide gel onto a surface of a supporting substrate to form a deposited graphene oxide gel thereon; c. partially or completely removing said fluid medium from the deposited graphene oxide gel layer to form a graphene oxide layer; and d. heat-treating the graphene oxide layer to form said unitary graphene layer or graphene single crystal at a temperature higher than 500° C.