The ‘Great Graphene Breakthrough’ – or what was really in the paper?

We’ve been inundated with people shrieking about the publication of a possible major breakthrough in the race to make commercial graphene.  For those who have been asleep due to some kind of magic spell and missed it all, graphene is a form of carbon that is basically a gigantic, one-atom thick layer of carbon atoms in a hexagonal array.  It is strong (for a one-atom thick layer, which isn’t saying much), conducts heat and electricity really well (again, for a one-atom thick layer) and is transparent and lightweight (it’s one atom thick, after all!).

The problem has been making large areas of graphene inexpensively.  There are really two ways to go on this.  One is, in the style of the techniques used by the two researchers awarded the 2010 Nobel Prize in physics, Geim and Novoselov, to somehow peel sheets of graphene off flakes of graphite.  The other is to grow the graphene from individual atoms of carbon, using a technique like chemical vapour deposition (CVD) or plasma vapour deposition (PVD).  Both are expensive, with the drawback to the graphite approach being that you make very small sheets that then need to be knitted together, and the drawback to the CVD/PVD approach being it takes an agonizingly long time, in a high vacuum system, to make this stuff and then you need to peel it off whatever it was grown on.

So imagine the furor in the press when researchers from Samsung’s Advanced Institute of Technology and Sungkyunkwan University in Suwon, South Korea, published their report in the Sciencexpress section of Science magazine, on 3 April.  There was breathless debate about whether this was THE breakthrough in graphene, with the conclusions running the gamut from “who can say?” to “who knows?” with an occasional “maybe…” thrown in.  My conclusion was that it was fairly obvious none of the people writing these conclusions had ponied up the $20 to read the paper.

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So, I spent the $20.  The title of the report is itself scary enough, “Wafer-Scale Growth of Single-Crystal Monolayer Graphene on Reusable Hydrogen-Terminated Germanium”.  If that doesn’t get the blood to pumping, then nothing will.  But to be serious, this actually is a breakthrough.  Don’t get me wrong, the graphene made this way is still going to be expensive, but it can be made in large sheets and can be made almost defect-free.

What the teams did was to start with a silicon wafer, the same type used to make integrated circuits.  They coated it uniformly with germanium, and then put a layer of hydrogen atoms over the germanium.  If you grow graphene on this, their reasoning went, then the carbon atoms will bind to one another instead of the hydrogen, and should peel off the hydrogen easily.  And if the hydrogen has a hole in it somewhere, the carbon won’t dissolve into the germanium metal.  All good so far.

The teams placed nucleation centers on the substrate.  Essentially, they put down small pieces of graphene to get the crystal to start to grow.  This is already commonly done when growing graphene this way on other substrates, like silicon carbide or iridium.  Then they used a low-temperature CVD process to put carbon atoms onto the surface, which formed graphene that mimicked the crystal structure of the metallic germanium underneath it, what is called epitaxial growth.  Those carbon atoms came from breaking down very pure methane, CH4.  But this way, a number of good things happened.

For one, the graphene didn’t stick to the hydrogen-terminated germanium substrate.  The researchers could easily peel it off without having to resort to chemicals or heat.  That’s very good because the substrate, which is not going to be cheap to make, is at least moderately reusable.  Another good thing is that the germanium and the graphene have similar expansion and contraction with heat, so not only does the graphene grow large and uniform, it isn’t in danger of wrinkling up like on some substrates that contract more than the graphene with a change in temperature.

So this is likely a way to produce bigger sheets of graphene to work on.  It won’t be cheap, owing to it being a CVD process at its core.  You can only lay down a single atomic layer of carbon atoms so fast, and high vacuum systems are not free.  But this is the first time big sheets of graphene have been made by any commercially-viable process.

Now, what are the implications for the resource sector?  Now I get to vacillate, and say it remains to be seen.  For one, we could all stop talking about how graphene is going to be great for the graphite industry.  Graphene doesn’t use much carbon at all, and this type of graphene doesn’t even need graphite in any way, since everything starts with CH4.  Graphite will do just fine without worrying about whether and when graphene will pull on demand, so we can relax.

The physical properties of graphene, but more importantly its price point, will tell us what the additional impact might be.  Graphene is a great conductor of heat and electricity for its weight.  Copper use could take a hit, but the amount of copper displaced in heat sinks and electrical conductors all comes down to the price difference between graphene and copper.  Right now, to me at least, graphene still looks like it is years away, and will remain a niche material rather than become a go-to replacement for basic metals and materials.  Technology exists to surprise, though, and we will definitely be hearing more about the properties of graphene after researchers get their hands on large-scale samples produced using this new technique.

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Jon Hykawy

About Jon Hykawy

Dr. Hykawy is President of Stormcrow, a Toronto-based business consultancy and independent research firm. He was previously Head of Global Research with Byron Capital Markets, specializing in the economics of critical materials such as lithium, vanadium, fluorspar, graphite and the rare earths. He has extensive experience in the solar, wind, and battery industries, having conducted significant research in the area of rechargeable batteries (including rechargeable alkaline, lithium-ion and flow batteries) and wind power technologies. Jon began his career in the investment industry in 2000 when he began work as a research analyst broadly covering the technology sector. His focus was later refined to clean technologies and alternative energy companies, and his current areas of interest continue to be dominated by the issues of supply of, and demand for, critical materials in a variety of global supply chains.
  1. Jon – Thank you for the above, however; allow me to draw your attention to some better data on where graphene is today and the real marketplace — China. And of course the data for this is on InvestorIntel.

    Hongpo Shen, a Sr. Editor here since May 2012 has published: China’s Graphene industry set to skyrocket in 2014
    Part II: China’s Graphene industry set to skyrocket in 2014

    This industry is here — it’s just cloaked in mystery….

    • Yeah, but, this is a vapor deposition process that uses natural gas. I didn’t see that coming. Did you? Good ol carbon. It can come from anywhere. This undermines the graphite to graphene story that presumes sloughing off layers of flake graphite and stitching them together is going to be the way to commercially viable graphene. Flake demand should be solid due to Li-ion batteries but as the good doctor says, we maybe shouldn’t count on graphene being the driver for graphite we’re assuming that it must become. Maybe the precursor is going to be methane and there’s plenty of that floating around.

  2. “… the graphene made this way is still going to be expensive …”

    Therein lies the chief obstacle to broad industrial and market acceptance. Electrochemical separation of graphene from graphite, which researchers believe in time, will be produced at pennies per pound, remains the process to watch and invest in for the future.

    • Which researchers believe this? The ones that I know believe exfoliation is a (relatively) cheap way to make little pieces of graphene, but stitching them together takes too many little seamstresses.

      For the overly literal, my comment regarding the seamstresses was facetious.

      Regardless, let’s look at some basic math again. Maher et al in 2012 reported that the areal density of graphene is 1,520 square meters per gram. The surface area of the land mass on Earth is about 149 million square kilometers. If I haven’t slipped about three decimal places, then we need about 98,000 tonnes of graphene to coat the land mass of Earth in the stuff.

      Compared to the amount of graphite out there, and assuming this is more than a one year job, this isn’t that much. It still seems to me that the winner in this game will be the company figuring out how to make cheap graphene from whatever source of feedstock is best, not some random graphite mining company.

      The other winners will be the jokers pumping graphene as the investment opportunity of today.

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