Producing Graphene at Scale

Process
1st January 2019

Article by Jason Stafford, Omar Matar FREng CEng FIChemE and Camille Petit

The challenge for chemical engineers

JUST over a decade ago, the isolation of graphene created a major stir in the scientific community. At the time, it was a material that many believed could not be stable enough to exist. But it was found not only to be stable, but to possess a range of properties so extraordinary that it is regularly labelled as a “wonder material” – a material that will revolutionise every aspect of our technological world. Such promise and attention has put graphene under the spotlight.

So when we look around at our emerging technologies, why has graphene apparently not delivered? In this article, we discuss one of the biggest challenges that is blocking its widespread adoption: how do we make high quality material on a large scale? It is the first step before it can be used in any technology, and a challenge which is particularly suited to the chemical engineering discipline.

What is graphene?

Graphene is in a category that’s known as a two-dimensional (2D) material. It is a flake made from carbon and is just one atom thick. This monolayer of carbon atoms is arranged in a 2D honeycomb lattice, illustrated in Figure 1 amongst other graphene-based materials. Graphene’s unique properties are what make it such an exciting prospect, which, if realised on a large scale, could have far reaching benefits to society. Its electronic properties, such as carrier mobility and current density, exceed many other conductors in use today. It is also an effective heat conductor, with a thermal conductivity that is several times greater than copper. In 2D form, it is the strongest material known. All this, and more, from a material which is 98% transparent.

Figure 1: Illustrations and micrographs of Graphite, Graphene, and the other forms of graphene-based materials [1]. Although graphene is a monolayer, the name has been used somewhat ambiguously to describe other useful forms of the layered material. These include few-layer graphene, graphene oxide, and reduced graphene oxide. Beyond ten atomic layers, the electronic properties of the material are no longer distinct from the bulk 3D graphite crystal [2]