Article updated by Liam Critchley on 22 December 2020.
Image Credit: BONNINSTUDIO/Shutterstock.com
A decade has passed since Andre Geim and Konstantin Novoselov won a Nobel Prize for their discovery of graphene. Hailed as a promising material with endless potential applications due to its unique properties, how far away are we from the mass production and commercialization of graphene?
What is Graphene and Why is it Special?
Graphene is a new material that was first isolated in 2004 at the University of Manchester. It is made up of a single atom layer of graphite - the same graphite used in pencil lead. Geim and Novoselov first isolated graphene by repeatedly separating graphite fragments with sticky tape until they created one-atom-thick flakes.
Although the team of researcher's discovery of graphene may sound simple, its structure is remarkable. Graphene has a two-dimensional crystalline structure; the atoms' flat layer consists of hexagonal rings of carbon atoms, which gives a ‘honeycomb’ structure. The layer itself is approximately 0.33 nanometres thick. Before graphene, it was believed that two-dimensional molecules could not exist due to thermal instability.
This structure gives graphene unique properties. Experiments have shown it to be the most robust material now known to us, being at least 200 times stronger than steel due to its strong electrostatic forces and lack of defects. Graphene is also an excellent conductor of heat and electricity thanks to its flat, hexagonal structure, meaning there is little resistance for electrons' movement.
As well as being extremely strong, graphene is a lightweight material weighing only 0.77 milligrams per square meter. It is also very flexible; research has shown it can be stretched up to 25% of its original length without breaking.
All these properties are remarkable on their own. However, it is the combination of them in one material that has led it to be dubbed a wonder material with the use of graphene applications in all different types of industries.
What is Graphene Used For?
Graphene’s properties open many doors for it to be used in various applications. Over 15 years since it was first isolated, many graphene products have come to the market and graphene use is expanding into new sectors year on year.
One of the markets where graphene uses first appeared was in applications with low entry barriers, such as sports equipment. Within this industry, the multimillion-dollar company Head has taken advantage of graphene’s strength and flexibility by incorporating it into the frame of a new tennis racket line, Grays has incorporated graphene into their hockey sticks, Vittoria and Goodyear have launched graphene-enhanced bicycle tires, and Standard Graphene in Korea has previously showcased a very lightweight bicycle frame infused with graphene.
Beyond sports equipment, sports clothing was another early adopter of graphene thanks to its thermal regulation and durability in textiles, with Deewear initially leading the way alongside Directa Plus. Inov-8, a sportswear brand, worked with the National Graphene Institute based in Manchester, UK, to release the company’s first graphene-enhanced running shoe in 2018, eventually expanding into a full range. Inov-8 states that the graphene-enhanced rubber is 50% stronger and 50% more elastic than regular rubber.
Beyond the sports industry, companies such as Graphene-X have been taking to Kickstarter to launch everyday-use graphene-enhanced jackets and pants with great success.
One area where the use of graphene has been trialed is in coatings, with both electronically conductive coatings (for printable circuits) and barrier coatings being developed, a lot of which have found a use for protecting the hulls of ships.
Graphene Sensors and Electronics
While the adoption of graphene into advanced technology is slower than in other sectors (due to higher entry barriers and enhanced safety requirements), several companies develop graphene batteries and supercapacitors for portable electronics. Graphene is now also used in the Huawei X10 phone as part of the cooling system, and there have been reports that graphene is being used in some of China’s military helicopters.
Graphene is, however, finding some use within specific electronic sectors, namely sensors, as the electronic properties and large surface area of graphene makes the sensors highly sensitive.
One exciting development has been the collaboration between CERN and Paragraf that led to a graphene Hall-effect sensor being developed that can measure magnetic fields.
Many of the available sensors are biosensors, which are used to detect specific viral strains (sometimes multiple strains simultaneously). In the COVID-19 era, some of these have been adapted for detecting COVID and others have come to market specifically as a point-of-use device for detecting if a person has COVID.
COVID-19 Graphene-Enhanced Face Masks
Researchers have also found other uses for graphene in the COVID-19 pandemic. For example, several companies worldwide have developed graphene-enhanced face masks to filter out the SARS-CoV-2 virus.
Use of Graphene in The Automotive Sector
One of the higher-tech industries that is seeing some impact from graphene use is the automotive sector.
Several companies have produced longer-lasting graphene tires, and Graphenoil lubricant has been developed to improve engine performance.
Graphene-enhanced parts in specific Ford models have been developed. It has been stated that every Ford car made from February 2020 onwards will have graphene in it to improve the vehicle's weight and structural properties.
Aside from the vehicles themselves, adding graphene to roads to improve their wear properties and reduce tire wear via potholes is another crucial area. This was first trialed in Rome by Directa Plus and Iterchemica, and now the Graphene Engineering Innovation Centre in Manchester is working with Highways England to find the best ways of adding graphene to roads in the UK.
Graphene Applications in Composites
Composites are an area where graphene use is seeing interest because only a small weight % (less than 1%) is needed to bring about added benefits. Notable companies to date include TLC Graphene, which integrates graphene into plastic resin composites while still making them commercially feasible from a financial standpoint.
NanoRegMed develops graphene for medical transplant composites, while First Graphene has integrated graphene into the fiberglass used in swimming pools.
Household Graphene Technology
Graphene uses have also made their way into different household consumer products. Specialists in lighting solutions, SERA Technologies manufactures an LED lightbulb with a graphene-coated filament. Reportedly, these bulbs are 10% more efficient than regular LED bulbs due to the graphene aiding the dissipation of heat from the bulb.
Standard Graphene has also produced graphene-coated non-stick pans.
Even in 2020, there are new ‘homestyle’ products coming to the fore, with Directa Plus announcing a graphene-enhanced leather for different furnishings.
An exciting product developed in 2020 was the SpaceMat from SpaceBlue in Manchester. The SpaceMat is a recycled rubber mat (recycled from rubber tires) that has been infused with graphene to improve its structural properties and can be used in both the home and place of work.
Use of Graphene in the Construction Industry
Of all the different sectors, the construction industry could be revolutionized the most from use of graphene.
Concrete contributes to around 8% of global CO2 emissions, but the addition of 0.03 wt% of graphene into the cement (the glue that holds the concrete together) within the concrete reduces the amount of material needed by up to a third. This directly translates to a 2% drop in carbon emissions for the concrete industry. Many companies are working in this area, including one of the longest running graphene companies, Global Graphene Group (GGG).
These examples show that graphene can be incorporated into many applications. Graphene has now made it into many sectors with low- to mid-entry barriers and is even touching on consumer products.
It will still be a while before we see widespread adoption in more high-tech applications, especially as many of these industries require long-term stability tests. However, as graphene is used in more industries, we will hopefully see more multi-national and advanced technology companies adopting graphene.
Why Has Graphene Not Taken Over the World Yet?
Work still needs to be done before there is widespread adoption of graphene, and several production issues need to be addressed before more advanced sectors opt for graphene.
One of the initial challenges of graphene production revolved around chemical vapor deposition (CVD). While it is the best method for producing single-layer graphene, it is not ideal in terms of scale. Therefore, the number of people who can manufacture graphene is limited.
Many sectors attempted to lift the graphene from copper foil sheets they were deposited on, resulting in defects. Nowadays, companies will deposit it directly onto a substrate of their choice, removing this issue altogether. This area's potential has been best showcased by Grolltex, which uses roll-to-roll methods and can produce CVD graphene at larger scales.
For most applications and products, exfoliation from graphite is the most scalable method. Many companies take this approach as it is the best way of producing large amounts of graphene. However, the nature of the technique means that varying-quality graphene is produced, all the way from a few-layers to beyond ten layers (where it officially becomes graphitic platelets instead of graphene platelets).
The issues here are well documented, as people have been known to receive vastly different graphene products from company to company, and even from the same company when ordered from different batches.
Much work is being done to tackle these batch-to-batch quality issues and to produce graphene at larger scales. Companies are now able to make more than 1 ton of graphene per year. How the graphene is used is most important, with cheaper, high-layered graphene being ideal for composites, and single-layered graphene being more suitable for sensors and electronics.
More is now being carried out to educate end-users on how to best use and integrate the different ‘graphenes’ into their intended application.
Graphene is currently at a tipping point. As some of these issues have been addressed alongside wider organic adoption thanks to improved market confidence in graphene, we will hopefully see graphene take over the world.
However, graphene will likely become an invisible additive and graphene will play a role in many aspects of our lives. Some companies may use it as a marketing ploy, but for the most part, its use is likely to go unnoticed by the general public, yet they will see the inherent added benefits that graphene provides.
The Future of Large-Scale Graphene Commercialization
The widespread use of graphene is slowly making its way into the modern world. It is important to remember that it took almost 70 years to create commercially viable lithium-ion batteries. While removing some of the quality issues and scaling up the production potential will be key drivers for wider adoption (as products that are the same batch to batch will drive up the market confidence), adopting a more green approach could also be the key to the future of graphene.
In an environmentally conscious world, graphene can make applications and production greener. While manufacturing and process industries are not known to be the greenest industries, a couple of graphene companies lead the way in this regard. For example, GrapheneCR has a carbon-negative process where they produce graphene from biochar.
Universal Matter has commercialized the ‘flash’ graphene process that transforms all forms of carbon-based waste into graphene (and sublimes any other non-carbon constituents).
While not all companies will focus on the green side, it is one aspect of large-scale graphene manufacturing to look out for, especially as some of the added benefits of using graphene in specific applications are lighter, greener products.
We are likely to see graphene production increase across the board, and regulatory groups such as the graphene REACH consortium will promote safe and high-quality graphene production in the future.
References and Further Reading
Woodford, C. (2020) Graphene - a simple introduction. [Online] Explain that Stuff. Available at: https://www.explainthatstuff.com/graphene.html
Villas-Boas, A. (2017) Samsung's new battery technology could charge smartphones in minutes, not hours. [Online] Business Insider. Available at: https://www.businessinsider.com/samsung-graphene-smartphone-batteries-could-charge-in-minutes-2017-11?r=US&IR=T
NanoGrafi. 60 Uses of Graphene – The Ultimate Guide to Graphene’s (Potential) Applications in 2019. [Online] Available at: https://nanografi.com/blog/60-uses-of-graphene/
Van Noorden, R. (2008) The Graphene Challenge. [Online] ChemistryWorld. Available at: https://www.chemistryworld.com/features/the-graphene-challenge/3004835.article
Milne, S. (2015) The Challenges Facing Graphene Commercialisation. [Online] AZoNano. Available at: https://www.azonano.com/article.aspx?ArticleID=3950
Nano Magazine, Critchley L. (2019) A look back at the emergence of Graphene products in 2018 [Online]. Available at: https://nano-magazine.com/news/2019/2/13/a-look-back-at-the-emergence-of-graphene-products-in-2018
Nano Magazine, Critchley L. (2019) Why Are There Challenges with Graphene Manufacturing? [Online]. Available at: https://nano-magazine.com/news/2019/4/13/why-are-there-challenges-with-graphene-manufacturing