Kevin Wyss, PhD chemistry student at Rice University, has written an explanation of why graphene is not produced in quantities that make it usable in industry in his November 29, 2022 essay for The Conversation (h/t Nov. 29, 2022 phys.org news item), Note: Links have been removed from the following,
“Future chips may be 10 times faster, all thanks to graphene”; “Graphene may be used in COVID-19 detection”; and “Graphene allows batteries to charge 5x faster” – those are just a handful of recent dramatic headlines lauding the possibilities of graphene. Graphene is an incredibly light, strong and durable material made of a single layer of carbon atoms. With these properties, it is no wonder researchers have been studying ways that graphene could advance material science and technology for decades.
Graphene is a fascinating material, just as the sensational headlines suggest, but it is only just starting be used in real-world applications. The problem lies not in graphene’s properties, but in the fact that it is still incredibly difficult and expensive to manufacture at commercial scales.
Wyss highlights the properties that make graphene so attractive, from the November 29, 2022 essay (Note: Links have been removed from the following),
… The material can be used to create flexible electronics and to purify or desalinate water. And adding just 0.03 ounces (1 gram) of graphene to 11.5 pounds (5 kilograms) of cement increases the strength of the cement by 35%.
As of late 2022, Ford Motor Co., with which I worked as part of my doctoral research, is one of the the only companies to use graphene at industrial scales. Starting in 2018, Ford began making plastic for its vehicles that was 0.5% graphene – increasing the plastic’s strength by 20%.
There are two ways of producing graphene as Wyss notes in his November 29, 2022 essay (Note: Links have been removed from the following),
… Top-down synthesis [emphasis mine], also known as graphene exfoliation, works by peeling off the thinnest possible layers of carbon from graphite. Some of the earliest graphene sheets were made by using cellophane tape to peel off layers of carbon from a larger piece of graphite.
The problem is that the molecular forces holding graphene sheets together in graphite are very strong, and it’s hard to pull sheets apart. Because of this, graphene produced using top-down methods is often many layers thick, has holes or deformations, and can contain impurities. Factories can produce a few tons of mechanically or chemically exfoliated graphene per year, and for many applications – like mixing it into plastic – the lower-quality graphene works well.
Bottom-up synthesis [emphasis mine] builds the carbon sheets one atom at a time over a few hours. This process – called vapor deposition – allows researchers to produce high-quality graphene that is one atom thick and up to 30 inches across. This yields graphene with the best possible mechanical and electrical properties. The problem is that with a bottom-up synthesis, it can take hours to make even 0.00001 gram – not nearly fast enough for any large scale uses like in flexible touch-screen electronics or solar panels, for example.
Current production methods of graphene, both top-down and bottom-up, are expensive as well as energy and resource intensive, and simply produce too little product, too slowly.
Wyss has written an informative essay and, for those who need it, he has included an explanation of the substance known as graphene.