Our period in history is defined by the materials our world is made of. My grandparents grew up in the age of steel. My parents saw reinforced concrete become mainstream. I grew up surrounded by plastics.
Now, we’re starting to see a completely new generation of materials – based on the engineering of substances down to the atomic scale. This has the capacity to usher in a range of applications that seem like science fiction. These range from membranes that generate power from water mixing, to the mind-boggling space elevator concept.
Today, we’re going to double down on one of the best-known of these new materials: graphene. To help us along the way, I’m joined by Ron Mertens of Graphene-info.
AL: Hello Ron, can you begin with a quick introduction to graphene?
RM: Graphene is a 2D material made out of carbon atoms, arranged in a honeycomb lattice. By a 2D material, I mean it is just one atom thick. Graphene was first isolated in 2004. However, it’s actually what graphite is made of – and graphite has been mined and used for thousands of years.
The researchers who first isolated graphene found that it has some remarkable properties. It is the world’s strongest material – 200 times stronger than steel. It’s also the world’s most conductive material, for both electricity and heat. Graphene is thin, flexible and transparent, and has excellent optical properties, too. Thanks to graphene’s host of amazing attributes, scientists and industry experts refer to it as a “miracle material”. They are excited about its potential to revolutionise entire markets.
AL: Can you tell us a bit about the history of graphene research?
RM: As I said, graphene was first isolated in 2004. Even though researchers knew about graphene for years, they never managed to actually isolate a single layer. This was solved in a simple method – using Sellotape to exfoliate graphite. If you attach the Sellotape to graphite, and then pull it off, you get flakes of graphite (which is very brittle). The researchers did this repeatedly, each time on the new graphite flakes – and eventually they had single-layer graphene sheets in there.
This method was simple, yet effective – and it landed the researchers from Manchester University the Nobel Prize in 2010. The UK considers itself to be the “birthplace of graphene” and has allocated hundreds of millions to build graphene research centres and accelerate R&D activities. To this day, the UK is one of the world’s central graphene hubs.
AL: What kind of uses does graphene have?
RM: Since the “discovery” of graphene, researchers all over the world started to study it, and it turns out that graphene can revolutionise entire industries. Possible graphene applications include bendable and transparent computer screens; strong and light composite materials; cheaply desalinated water using graphene membranes; low-cost and efficient solar panels; lightning fast computers; light and powerful batteries that charge within minutes; unique sensors; and much more. Graphene’s full range of possibilities seems to be a long way from being discovered.
AL: All these applications sound great. Can you give some specific details on graphene batteries?
RM: Batteries are important in many areas – including electric vehicles, mobile phones, and more. Battery technology is advancing, but currently very slowly. Graphene may prove to be the key to batteries that are both longer lasting, and faster charging. Graphene is the material with the highest surface area to volume ever – it’s basically all surface! It’s therefore highly suitable to be used as an electrode – because surface area is what matters when it comes to high power, and fast charging times.
Many companies are developing graphene-based batteries, which are now starting to enter the market – although it will probably be some years before we actually see mass-produced graphene batteries for electric cars.
AL: Besides batteries, where is graphene being used today?
RM: The first commercial applications of graphene are in composite materials. It turns out that adding even a trace amount of graphene to metals, plastics, rubber or even carbon fibre can make these materials much stronger. We are already seeing some products that use graphene, on the market. The first ones were sports equipment such as helmets, tennis racquets, skis and bicycle wheels.
Graphene is a great conductor, and it is also flexible and transparent. This makes it suitable for touch displays (to make the transparent conductive wires). This was probably the first application that people had in mind back in 2010 or so. While graphene-based touch layers are indeed available today, this is actually not an application that graphene seems to be winning at. Other applications now entering the market include graphene batteries and supercapacitors.
AL: I didn’t realise that a material can be both transparent and conductive. How does that work?
RM: Yes, this sometimes confuses people. Transparent conductive materials are used in many applications – such as touch screens and OLED [organic light-emitting diode] displays. The most common material today in such applications is indium tin oxide (ITO). These materials aren’t 100% transparent – but it’s enough to be transparent to our eyes. A single layer of pure graphene absorbs about 2.3% of the light that goes through it.
AL: Will graphene be used to make faster and more efficient chips in the future?
RM: Graphene is the world’s best conductor – which is great for many applications, but transistors are made from materials that are semi-conductors, in which the conductivity can be controlled. In order to do that, the material has to have what’s known as a “band gap”. Graphene normally doesn’t have a band gap – which means it’s highly conductive, but it’s therefore not a good material to base transistors on. A band gap can be introduced by several methods, such as cutting graphene into a ribbon shape. Researchers are currently looking into such solutions.
On the other hand, the graphene hype spurred research into other 2D materials, and now there are dozens of comparable materials – including 2D sheets made from MoS2 [molybdenum disulphide], and silicon (called silicene). Some of these materials have an inherent band gap. Therefore, it’s more likely that future transistors will be made from MoS2, for example, than from graphene.
AL: What are the major challenges in the graphene industry?
RM: Graphene is still expensive to make, and some types of graphene are only produced in limited quantities. This makes it difficult to utilise it commercially.
One of the biggest challenges at this stage is standardisation. There are several types of graphene, and dozens of companies that produce it – each with different properties and price points. If you want to adopt graphene in your product it may be very difficult to choose the correct type.
AL: Graphene sounds like it is indeed going to be a very important material. Do you have any investment comments, for people keen to cash in on the graphene revolution?
RM: Graphene is being researched by a very large number of universities in the world. Furthermore, many large companies are working on this material – including Samsung, LG, Nokia, Sony, IBM, Intel and Apple.
The EU launched a ten-year €1 billion project (called the Graphene Flagship) to accelerate R&D – and the UK invested similar amounts in graphene research centres. We have seen massive investments from large companies, as well as many smaller startups in this area.
Following the hype on graphene, several early-stage graphene companies went public in recent years. It is not going to be an easy task to pick the winners, and we even know of some scam operations that try to lure innocent investors.
At Graphene-info we publish on the investment opportunities in this industry, because we’re well aware of how hard it is to keep abreast of the latest developments. It’s such a technical and fast-moving field. The site was launched in 2009 as a knowledge hub focused on graphene – so we’ve a long history, relative to the age of the field. Our site quickly grew and is now read by tens of thousands of readers each month. It’s a great place to check out the latest news.
We’d love to hear your views on graphene specifically – and nanomaterials in general. Please do let us know where you think the opportunities lie. As usual, you can email firstname.lastname@example.org.