Ever since it was first discovered in 2004, graphene has been hailed as one of the most important breakthroughs in materials since the plastics revolution more than a century ago. A million times thinner than human hair, but 200 times stronger than steel1. The early predictions were that graphene would almost immediately enable the kinds of products and technologies that we’re used to seeing in sci-fi movies. Cut to more than a decade and a half later and that still hasn’t happened. Not even close. With opinions split between people overhyping graphene or calling it a massive disappointment, it’s time we got to the truth of what is really happening with this so-called ‘wonder material’.
What is graphene?
The hype around graphene is hardly surprising: a manmade substance with extraordinary properties. It’s incredibly versatile and conductive, and is predicted to heavily disrupt industries ranging from consumer electronics to aerospace for a while now. But even though progress hasn’t been as fast as many would have hoped, researchers and product makers are now, at last, beginning to make some headway.
Before we go on to what it can do, let’s first take a look at what graphene actually is. To put it simply, it is fundamentally a single layer of graphite – the material used to make pencil. But instead of having a three-dimensional crystalline structure like graphite, graphene is two-dimensional, meaning it’s just one atom thick, with the atoms arranged in a hexagonal lattice or honeycomb arrangement – a bit like chicken wire.
This structure is important because it allows each carbon atom to be covalently bonded to three more around it, and the strength of these bonds is one of the main reasons why graphene is so strong and stable2. Another reason is because the atoms delocalise electrons – meaning they can move around more freely3 – and this is what makes graphene so good at conducting electricity and heat. In fact, it’s the most conductive material that we’ve ever come across.
You’re probably thinking that the process of discovering this amazing material must have been so mind-bogglingly complicated that us mere mortals couldn’t possibly comprehend how it was done, but it was actually almost laughably simple. It was first isolated – aka extracted from graphite – by two researchers, Andre Geim and Kostya Novoselov, at the University of Manchester in the UK back in ‘044. How did they do it? By using sticky tape on a piece of graphite and peeling it off, folding it and repeating the process over and over again until they ended up with a single layer of graphene5. Yep, it really was as easy as that.
Although graphene was known to exist as far back as the 1940s6, the discovery was widely celebrated by the scientific community. Geim and Novoselov were awarded the Nobel Prize for Physics in 2010 – and it immediately generated huge levels of excitement about the material’s possibilities and potential uses in what many people hoped would be the not too distant future. Expectations ranged from using it to replace silicon transistors in electronics in the short term, all the way to building the immense cable or tether that would be needed for a space elevator out of graphene in the future7, although I think we can all safely say that idea is a little way off for the time being.
So, what exactly has been holding it back? Why is the market not flooded with graphene-based products when we’ve known how to make it for years? When graphene was first isolated it was done in tiny amounts, and one of the main issues since then has been how to scale up production of the material while ensuring the quality of graphene you end up is good enough for the applications that it is intended for.
When the process of mass producing the material is – at least for now – very complex and expensive, graphene products need to be significantly better than what’s already out there for them to be considered worthwhile. If they’re not as good as the material they’re trying to replace, or there’s very little noticeable difference, then why bother? For example, silicone is an excellent material for use in electronics because of its special semiconducting qualities, and many experts don’t see it as having many weaknesses. So if graphene is going to knock it off its perch with the added cost and hassle needed to make it, then it’ll need be a true game changer once the production methods have matured enough.
This was the problem with the first products that came out which included graphene in some form. Many of the early entrepreneurs that were first to bring it to market ended up disappointing their customers and investors with products that did technically incorporate graphene, but didn’t sufficiently outperform what was already out there despite costing considerably more8. It was too soon; not enough follow-up research had been done at that stage and it actually put a lot of people off graphene as a marketable material for a while.
Progress and breakthroughs
Fortunately, researchers have been testing a range of new approaches to mass producing graphene in recent years, and the results that we’re starting to see are very promising, which is just as well, otherwise we’ll be needing a LOT of sticky tape to build that space elevator.
One of the most popular and well-tested methods is a process called Chemical Vapor Deposition or CVD, where graphene is effectively grown on a metallic surface, like copper, by combining carbon-bearing gases inside a high-temperature reaction chamber9. This leads to graphene being deposited onto the metal, which can then be separated and transferred onto the substance that needs enhancing. But doing it this way requires large amounts of energy, only yields small amounts and relies on the use of harsh chemicals that can create a toxic by-product, which is why others have gone in search of cleaner, cheaper and less power-hungry ways of making graphene.
One new approach that has caught the eye of experts in the field is called flash graphene, which has been described as a way of “turning trash into treasure.” This involves taking virtually any material with high carbon content, such as used rubber tires and even some mixed plastics, and converting it into graphene in an instant. The material is heated to 3,000 Kelvins – that’s approximately 5,000 degrees Fahrenheit – in just ten milliseconds. This causes all of the carbon-to-carbon bonds to break and reconstruct as ‘turbostratic’ graphene, which has misaligned layers that are easier to separate. Its creators, a team at Rice University in Houston, hope to produce a kilogram of graphene a day within two years10,11.
Others have been experimenting with new and emerging technologies, such as 3D printing, to see whether they could be used for graphene production. Researchers at the Massachusetts Institute of Technology successfully printed a number of 3D objects from graphene and compared the results with conventional materials. Some of the pieces came out ten times stronger than steel at one twentieth the mass12. Scientists have also experimented with dispersing graphene in water, which would allow it to be sprayed onto a surface as a coating. A team at Umeå University in Sweden has created a thin film of highly conductive material from a dispersed graphene solution13. They are hopeful that this be used to create electrodes for supercapacitors, which are advanced storage solutions that can charge much quicker and degrade less than batteries, but can’t yet hold much energy14.
While the plentiful supply of this wonder material remains a work in progress, we are now finally starting to see the release of graphene-based products that actually do seem to offer significant, tangible benefits over what their competitors have been making for years with industry standard materials. A company called Real Graphene has created a graphene-enhanced lithium battery that is thought to be on the verge of commercial use. It can cut phone charging time from an hour and a half to 20 minutes, lasts three to five times longer than conventional lithium batteries and generates less heat. This was achieved by mixing graphene in with the lithium and introducing a composite layer of graphene15. Touch screens made with graphene are thought to be on the horizon as well. They could be printed on thin plastic rather than glass, which would make them light, flexible, shatterproof and therefore ideal for smartphones16. Wearable electronics made using graphene that integrate directly with fabric clothing are also believed to be achievable in the next few years.
Graphene’s high-strength and heat-conductive properties make it an excellent material for a variety of protective equipment too. Italian motorcycle helmet manufacturer Momodesign now offers a range of helmets with graphene-coated exterior shells. According to the company, the presence of graphene improves the distribution of any impact force and dissipates heat faster than conventional materials, increasing protection from thermal degradation17.
Another Italian company, Italcementi, has proposed graphene-infused cement, which could lead to houses that don’t require wiring as the building material is already highly conductive on its own. Graphene’s thermal properties allow for walls that easily dissipate heat, potentially eliminating the need for air conditioning units in hot countries18. With demand for fresh water around the world also on the rise, graphene may have the answer to this challenge too. Physicists in China and the US have invented a graphene-based desalination membrane that can remove salt from seawater. It’s a combination of a single graphene sheet and a carbon nanotube mesh, which creates a centimeter-sized membrane. Desalination can already be done with evaporation, but this uses a lot of energy. Reverse osmosis is another method, but better membranes have been needed for years19.
It could even kill bacteria and help save lives. Researchers at the Chalmers University of Technology in Sweden have shown how attaching ‘vertical graphene flakes’ to the surface of medical implants protects them from bacterial infections. This could eliminate the need for antibiotics and lowers the chance of implant rejection, which is actually surprisingly common20. In fact, healthcare is now one of the leading sectors for graphene applications21. Its ultra-thin thickness is ideal for flexible circuits, a potential new way of monitoring people for health purposes, or possibly harnessing energy from the wearer22. They could be worn on the skin in the form of ‘smart patches’, integrated into contact lenses or at the extreme end used to create tiny sensors that travel in the bloodstream23.
Although experts and the media have been saying this for more than a decade, it does feel as though we are on the cusp of the long-awaited graphene era. Research has come a long way in recent years, mass production now looks feasible, we’re seeing products launched that demonstrate the material’s power and the list of realistic applications appears to be growing by the day. The thing I think a lot of people lose sight of is that there’s a pretty wide gap going from lab to mass produced product. It will take time for some of the more ambitious proposals that we’ve covered here to see the light of day, if they ever do, but there are still lots of reasons to be excited about the future of this incredible material.
1: Graphene-XT – http://www.graphene-xt.com/en/
The strength of graphene explained – http://www.youtube.com/watch?v=hvonBXvhCc4
2: Graphene-Info http://www.graphene-info.com/graphene-structure-and-shape
3: The Design Museum – http://designmuseum.org/discover-design/all-stories/graphene-will-it-change-the-world#
4: University of Manchester – http://www.graphene.manchester.ac.uk/learn/discovery-of-graphene/
5: Physics World – http://physicsworld.com/a/how-to-make-graphene/
6: Encyclopaedia Britannica – http://www.britannica.com/science/graphene
7: Institution of Mechanical Engineers – http://www.imeche.org/news/news-article/feature-graphene-revolution-remains-distant-despite-increasing-affordability
8: American Scientist – http://www.americanscientist.org/article/mass-producing-graphene
9: Graphenea – http://www.graphenea.com/pages/cvd-graphene#.XrWnS1NKjfY
10: ScienceDaily – http://www.sciencedaily.com/releases/2020/01/200127134751.htm
11: Luong, D.X., Bets, K.V., Algozeeb, W.A. et al. Gram-scale bottom-up flash graphene synthesis. Nature 577, 647–651 (2020) – http://doi.org/10.1038/s41586-020-1938-0
12: American Scientist – http://www.americanscientist.org/article/mass-producing-graphene
13: New Atlas – http://newatlas.com/materials/graphene-oxide-dispersion-paint/
15: Digital Trends/Real Graphene – http://www.digitaltrends.com/features/real-graphene-battery-interview-samuel-gong-ces-2020/
16: Encyclopaedia Britannica – http://www.britannica.com/video/187052/applications-graphene-material
17: Graphene Flagship – http://graphene-flagship.eu/material/GrapheneApplicationAreas/Pages/Graphene-Products.aspx
19: Physics World – http://physicsworld.com/a/graphene-and-nanotube-mesh-filters-salt-from-water/
20: The Engineer – http://www.theengineer.co.uk/vertical-graphene-spikes-bacteria/
21: Prescient Strategic Intelligence – http://www.globenewswire.com/news-release/2020/04/23/2020702/0/en/Growing-Usage-of-Graphene-in-Medical-Sector-to-Push-Graphene-Market-Revenue-past-646-8-Million-by-2030-P-S-Intelligence.html
22: Graphene-info.com/University of Cambridge/Jiangnan University – http://www.graphene-info.com/researchers-develop-washable-wearable-graphene-capacitors-can-be-woven-directly-clothes
24: Science Learning Hub (New Zealand) – http://www.sciencelearn.org.nz/resources/1777-superconductivity
25: Scientific European – http://www.scientificeuropean.co.uk/graphene-a-giant-leap-towards-room-temperature-superconductors
26: Phys.org – http://phys.org/news/2020-02-superconductivity-graphene.html
27: Physics World – http://physicsworld.com/a/squeezed-graphene-becomes-a-superconductor/