Graphene, the coveted material of the future
Published 2 May 2017 by Nicolas Barrial
Thin as an atom, stronger than steel, and the best known conductor of electricity, graphene is a revolution. But patents are piling up, as are prototypes, and we can’t wait to use it in our everyday lives.
Graphene, or rather a graphene sheet, is composed of carbon atoms arranged in honeycombs. This regular pattern results in a crystal so fine that it’s called two-dimensional. One sheet of graphene is one million times finer than a strand of hair—the thickness of an atom. While very flexible, graphene is 200 times stronger than steel. But it’s graphene’s conductivity that blows minds. Simply put, the electrons move as if they had no mass—70 times faster than silicium.
Nothing that can’t be fixed with adhesive tape
Graphene’s crystal structure has been long theorized, but it wasn’t until 2004, at the University of Manchester, that two Russian-born physicists, Andre Geim and Konstantin Novoselov, produced a sheet of graphene by exfoliating graphite (the tip of our pencils) with… adhesive tape. This discovery earned them the Nobel Prize in 2010.
Graphene is seen as dope for technology—smaller transistors, flexible screens, Internet 100 times faster than fibre optics, lighter airplanes and vehicles, longer-lasting batteries, faster-charging photovoltaic cells, etc.
From 2011 to 2013, nearly 1,500 patents have been filed, three-fourths of them Chinese. Stunned, the European Commission launched the Graphene Flagship project in 2015. With a budget of 1 billion euros over 10 years, it supports 23 countries, including pre-Brexit UK, which bought the University of Manchester a National Graphene Institute with 63 million pounds (75 million euros).
Graphene research at the University of Manchester:
Last April 3, researchers at the same University of Manchester published their findings in the journal Nature Nanotechnology to present graphene’s potential for desalinating sea water. In this case, it was graphite oxide, easier to obtain than graphene, but which presents impurities and structural defects. Indeed, laboratories can barely isolate by exfoliation half a gram of pure graphene per hour.
€100 per gram
However, the industry has accelerated the process using chemical vapor deposition (CVD), where the decomposition of a carbonaceous gas on heated metal deposits a layer of graphene. Although a study announces a production of 3,800 tons in 2027, only 60 tons were put to use in 2015, or 25% of the world’s production. The 100€-per-gram price isn’t the reason, it’s the lack of outlets.
But a strong demand could also have adverse effects. Natural graphite is abundant, and economic savings on scaled production could make the price of graphene plummet. Investors with cold feet are forcing the companies to diversify their offerings—while research tempers graphene’s unstoppable conductivity, for example. Silicium, which graphene is supposed to replace, still has an advantage: it’s a semiconductor that blocks electrical current under a certain threshold—the definition of a transistor.
Few products and lots of prototypes
Meanwhile, graphene-based products can already be found on the market: conductive ink, flexible mobile battery strap, graphene-component earphones, even tennis rackets. Graphene batteries are now commonly used to power drones.
For the rest, we’re still waiting as more and more prototypes begin to materialize, such as these graphene-based 3D printed objects, 10 times stronger than steel, presented by MIT last January 6.
MIT demonstration of graphene-based 3D printing:
Last March, prostheses that could be recharged by solar energy through their graphene skin were the pride of the University of Glasgow. One year ago, we reported on graphene aerogel, the printable matter that’s lighter than air discovered by researchers from the University at Buffalo in New York State and Kansas State University. In August 2016, Dutch researchers evoked “mechanical pixels” in a scientific journal—a symphony of colors resulting from pressure on graphene covered with silicon oxide.
Manufacturers are not far behind. In September 2016, scalded by exploding battery scandals, Apple filed a patent for a heat dissipator made of graphene.
Where are the fablabs in all this?
Is graphene too expensive for group experiments? While the price of graphene sheets remains high, graphite oxide powder, which can be used to make paper or conductive ink, for example, is more affordable… short of isolating graphene yourself, as in this project (in progress) at Electrolab in Nanterre, France, titled “Reproducing the synthesis of thin layers of graphene by laser exfoliation of graphite oxide using a LightScribe DVD burner”. Is a Nobel Prize on the horizon?
More about the European project Graphene Flagship