Interview: NPL's Dr Andrew Pollard talks graphene

Since its isolation and initial characterisation at Manchester University in 2004, graphene has become something of a hot topic. Classified as an advanced material, the single-atom thick carbon lattice carries a range of unique properties stirring up an eagerness in scientists, engineers and manufacturers globally to unlock its wide-ranging potential.

One of those excited by its potential is the National Physical Laboratory’s Dr Andrew Pollard, who has been leading the lab’s research into the standardisation and commercialisation of the nanomaterial. Pollard has been working with nanomaterials for around 15 years, having joined NPL 11 years ago where he explained that the focus has been around the metrology and measurement science around nanomaterials, particularly 2D materials such as graphene.

“The work we do at NPL as a metrology institute is focused on measurements — we’re not necessarily making products, but we’re helping companies in the UK and elsewhere to enable them to innovate,” Pollard said.

As the UK’s National Metrology Institute, NPL’s work involves developing and maintaining a national measurement infrastructure for the UK through the National Measurement System (NMS). Based in Teddington, Middlesex, the laboratory is owned by the UK government’s Department of Business, Energy and Industrial Strategy (BEIS) and its work provides vital support in measurement standards across industries ranging from healthcare through to  IT and communications.

“The key science we’ve been [working on] is understanding the measurement of what is essentially quite a difficult material — it’s nanoscale so it’s actually an atom-thick layer of carbon,” said Pollard in reference to NPL’s graphene research. “Being able to measure it in ways that are not only accurate and precise, but also enabling ways of quality control for companies in the UK and in the world, is actually a very big challenge.”

Notable for its thermal and electrical conductivity as well as its strength and flexibility, the addition of graphene into existing materials could lead to improved quality and efficiency of a huge variety of products, from batteries in wearable technologies through to composite materials in the aerospace and low carbon transport sectors.

“It becomes very exciting because you can get multiple improvements in products that you or I, or the general public, would use,” said Pollard. “One of the real benefits of graphene is that there’s a really broad array of very different applications of technologies, so we’re looking at working with companies in many different areas to help them with not only the measurement understanding of the material but also the intermediates and the final product.”

One example is its potential use within the construction industry, where the addition of tiny amounts of graphene to concrete can be used to improve strength and water resistance, and actually reduce the amount of concrete required by as much as 20 per cent.  “Concrete is the most abundant manmade material on Earth and actually contributes to around 8 per cent of UK carbon emissions,” he said. “If you can use 20 per cent less concrete, suddenly you’re having a big hit on those CO2 emissions.”

From a sustainability point of view, the wide-ranging benefits of graphene across various industries is seen as a real game-changer by Pollard and his NPL team. And concrete is merely one example of how the material could play an important role in the fight against climate change.

Graphene could also prove key to the development of energy storage technologies, he added,  with the addition of small amounts of the material being used to improve energy density in supercapacitors, as well as improving stability of new batteries such as lithium-sulfur as a sustainable solution for electric vehicles.

Yet another potential application area is the use of graphene additives to improve the environmental sustainability of car tyres.

Pollard explained that each year, billions of car tyres are burned or buried, whereas the addition of a small amount of graphene alongside virgin plastics could enhance recyclability and allow for these to be repurposed.

Meanwhile, in sectors such as aerospace where companies are grappling with the challenges required to develop new low-carbon technologies, graphene could play an important role in the kind of next generation lightweight composite materials that will be key to emerging technologies such as electric vertical take-off and landing) aircraft eVTOL.

Whilst we’re already beginning to see an increase in the use of graphene in applications ranging from sporting gear to smartphones and even cars, Pollard stressed that there are still considerable challenges around commercialising the technology at a manageable cost.  And one of the biggest obstacles to delivering on this potential, he said, is the ambiguity around standardisation and quality control of graphene. NPL’s work in metrology and the characterisation of graphene will, he said, be key in giving confidence to companies wishing to utilise graphene in their products.

Pollard explained that a product labelled ‘graphene’ can come in many forms, be it a powder, a liquid dispersion or a slurry. “Knowing these properties, for example the size of the particles in the powders, both thickness and lateral size are going to have an impact on the final product and the performance of the product you’re going to make, sell and use,” he said. “If you don’t know what those properties are, you’re not going to be able to judge if it’s the right material that you want to use.”

We need to have a methodology that everyone can use and therefore everyone can measure it in the same way

“Some materials will, for example, be very good for a composite, but won’t be for a battery, and vice versa, you might want very different properties there… that’s where we’ve been coming in across the world developing international standards particularly. Showing that actually, we need to have a methodology that everyone can use and therefore everyone can measure it in the same way. That gives an accuracy and precision that we can define.”

NPL’s work, alongside Manchester University’s National Graphene Institute (NGI) has been supporting this demand with research into the physical, structural and chemical characterisation of graphene. In March, the first international graphene measurement standard was published within the ISO (International Standards Organisation) to define the structural properties of graphene products. This followed terminology standards developed several years previously, allowing for precise definitions of types of graphene such as graphene oxide and few-layer graphene.

Further work being carried out by NPL includes developing a measurement standard for the chemistry of the material, looking at more specific in-depth standards for graphene oxide and establishing fast methods of quality control that can be done quickly and cost-effectively by companies that have scaled up the material. Pollard and his team have worked closely with producers, modifiers and users of graphene products such as First Graphene, Haydale, Cambridge Nanosystems and Thomas Swan amongst others.

Pollard believes that over the next 20 years, the full potential of graphene will begin to show in a wider ranging variety of products and applications.

“It’ll be everywhere in our everyday lives and we won’t notice,” said Pollard. He gave examples ranging from our houses being built from sustainable graphene-based materials, through to sensors that could be used to develop greener, smarter cities and areas such as new materials for new modes of transport  through to electronics.

“The UK is where it was first isolated and we’ve got world-leading expertise and academia and companies here, but it is very global so actually being able to trade and have those supply chains across these countries — it’s the international standardisation that enables that,” he concluded.