By Liam Britnell, former application manager of the Graphene Engineering Innovation Centre
Materials are, quite literally, all around us. Unless you’re reading this naked in a forest, nearly everything around you and worn by you comprises some combination of manufactured materials. Understanding the nature of these materials and their similarities and differences enables us to drive innovation and make more sustainable development choices.
In the 1960s, William Baker, president of the esteemed Bell’s Labs, proclaimed materials as “the grand alliance of engineering and science”. In the intervening years, every avenue of materials has developed significantly and there is an ecosystem of advanced materials research and development growing in the UK’s North West. At the heart of this ecosystem is the University of Manchester’s Graphene Engineering Innovation Centre (also known as the GEIC or ‘geek’) – see box.
Graphene is the first of more than 1,000 two-dimensional (2D) materials that have been developed since 2004, when the team of Sir Kostya Novoselov and Sir Andre Geim first made their groundbreaking discovery in the Department of Physics at The University of Manchester. Graphene has received much research interest since its discovery, and industry interest was accelerated by the Nobel Prize in Physics 2010 awarded to the pair for the discovery and elucidation of its properties.
Graphene has entered the public consciousness, featuring in science programmes (www.//is.gd/sugifo) and even sitcoms (www.is.gd/edeyed). For those looking to scratch a little further below the surface, one might reasonably ask “what is a 2D material?” and “what sparks such interest in using them?”
What is a 2D material?
‘2D materials’ is the name given to atomically thin crystal platelets, typically ‘exfoliated’ from layered 3D counterparts. Often, this strict definition is relaxed to include few-atom-thick platelets composed of several layers. 2D materials are typically derived from anisotropic layered materials such as graphite which have strong in-plane bonding and relatively weak bonding between planes. Graphene itself has been discussed from a theoretical standpoint since the mid-1940s as component of graphite; an important material in the early days of the nuclear age.
The layers of a material can be separated by various techniques. The separation of these planes often results in a material with properties which diverge from the parent material. This might be change of electronic band gaps or optical properties, for example. Using these materials in applications necessitates using them in an artificial heterostructure or in some form of composite material.
Graphene in particular has a range of properties (www.is.gd/ql88tQ) which make it useful for applications. It is highly electrical and thermally conductive; it is 98% transparent, can stretch 20% of its length without breaking and has unique electrical and optical properties. Furthermore, graphene is chemically modifiable and it is possible to ‘edit’ these properties for different applications. One example is graphene oxide, which when it is water-solution processed becomes an electrical insulator.
So why did graphene falter after the initial wave of excitement that these properties generated?
The reasons are perhaps too complex to examine in great detail here but, importantly, it has, until quite recently, been difficult and expensive to produce in high quantity and quality, and there has been a lack of skills in industry to use it effectively.
The skills problem has changed, as now several generations of PhD students have migrated into industry, taking with them a deeper understanding of how to handle and use graphene’s properties.
The efficiency and scale of production of these materials, which has long been a problem, has seen a step change in recent years, with notable examples including companies such as cycle component manufacturer Sixth Element and NanoXplore. In May, the latter company, based in Canada, announced that it has entered into a long-term supply agreement with Molding Products LLC to produce and sell graphene-enhanced sheet moulding compound called GrapheneBlack SMC, used to create high quality, lightweight composite exterior and battery enclosure parts for cars and trucks, such as bonnets, bumpers, roofs and battery packs. The material promises to deliver a weight reduction of up to 15% vs typical composite parts while also improving surface finish, paintability, and crack resistance.
The accompanied cost reductions at scale now bring some grades of graphene below higher grades of carbon black and other common additives used widely across many industry sectors. A recent estimation of worldwide sales volumes put graphene at 1,000 tonnes scale in 2022. We have also seen consolidation of suppliers and joint ventures forming, as in last year’s deal in which Black Swan Graphene acquired processing technology from, and started a new venture with, Thomas Swan.
Since 2011, researchers have shown the graphene can be derived from waste sources and more recently developments by James Tour at Rice University, using a process termed ‘flash graphene’, showed it can be produced from waste plastic. It can also be converted from various biomass sources, opening up a potential large scale, low carbon footprint production route, essential at a time when all materials suppliers are re-evaluating their environmental impact.
Graphene’s impact era
We’re at the beginning of the impact era for graphene. This massive potential and significant investment is starting to bear fruit and benefit society and the economy. No longer is graphene the preserve of supercars, such as in 2016 when Briggs Automobile Company (BAC) created graphene-enhanced carbon fibre composite wheel arches for its Mono supercar (pictured, above). Ford now uses graphene components in its engine bay in all new models to reduce engine noise by 20% using graphene-PU foams. Huawei uses graphene-enhanced thermal films to reduce working temperature in its range of high-end smartphones. The graphene industry in 2021 was worth $570m and is expected to continue growing at 16% per year over the next decade.
In composite materials, graphene can allow increase in strength-to-weight ratio in a broad range of materials from elastomers and commodity plastics to ceramics, metals and construction materials (XG Sciences material test on graphene sample pictured above). A trend in the last 12 months has been the developments in graphene-modified construction materials including concrete, cement and recycled plastics, which are all noted as sustainable replacements for traditional building materials. In an ongoing collaboration between Nationwide Engineering and GEIC (pictured above), it was found that up to 30% less concrete could be used in floor slabs, which translates to a 20-30% saving in CO2 emissions.
Another success story that has come out of the labs at The University of Manchester is Inov8 trail running shoes. Inov8 is a sportswear company based in the UK’s Lake District, geared towards trail and off-road runners. The company collaborated with The University of Manchester on engineering materials for their products. Now in the second generation, the graphene modified trainer materials exhibit high performance and durability. The first developments started with graphene-rubber composite soles branded G-Grip, which allowed simultaneous improvements in grip and wear resistance. More recently the team has developed graphene modified foams for the midsole which is said to offer a better return and longer lifetime. The G-Fly foam midsole was launched in 2021.
More forward-looking research from the Graphene@Manchester ecosystem includes pioneering work from Kostas Kostarelos’s Nanomedicene Lab, using graphene brain implants to greatly improve our understanding of conditions such as epilepsy. These implanted devices provide outstanding spatial mapping and information-rich recording of epileptic brain signals over weeks without being rejected by the body. Translating this research into a clinical setting may offer the possibility to hone in more precisely on the regions of the brain responsible for epileptic seizures and allow for better clinical outcomes and we hope that in time it can be applied traumatic brain injury, strokes and migraines.
2D materials have an enormous potential to enhance and change the way we live and only through open collaboration between research technology organisations, such as the GEIC, and UK industry will we realise this potential. Graphene is – in its most simple expression – a bit of pencil lead, but it has opened our eyes to what is possible when you look again under the microscope.
BOX: Geeks unite
The GEIC, which opened at the end of 2018, is a £60m facility providing industry with access to expertise and state-of-the-art equipment for development and scale-up of graphene and 2D materials and technologies. It works across six themes: composite materials, membranes and coatings, printed electronics, energy storage, construction and material production and characterisation.
The GEIC and similar institutes elsewhere are an important part of the R&D ecosystem for advanced materials, as development faces several critical challenges. Typically they are at least two of the following development models: radical, generic and upstream. ‘Radical’ means they are disruptive to established sectors and supply chains. Advanced materials are not commodities; they do not necessarily have a well-formed supply chain and this puts a break on market uptake. ‘Generic’ means they can be applied across many sectors, and the resource shortage in most SMEs driving the development can be wasted in a ‘search and destroy’ approach to different application sectors. This is critical as many material development start-ups often close down due to lack of funding before finding an appropriate product-market fit. Lastly, they are ‘upstream’, meaning the early producers – often university spin-outs – are distant from the end users and the necessary dialogue about proper usage (up to downstream) and market requirements (down to upstream) is slow and becomes mistranslated through intermediaries in the value chain.
A collaborative research space such as the GEIC, which allows suppliers and end users room to co-develop new products and technologies, is essential to tackle these challenges and reduce time to market. Many more established advanced materials, such as carbon fibre-reinforced plastics, have crossed this ‘valley of death’, but many years and many millions of dollars have been expended in the process. Institutes such as the GEIC should learn from these developments and aid innovative companies in newer materials such as graphene and the wide family of 2D. -Liam Britnell
