Manufacturers’ Monthly Material of The Month Part 2: Graphene

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Graphene, physically isolated only a decade ago, has the potential to change the world. Brent Balinski reports on what it is, why it’s creating so much excitement, and what it might offer Australian industry.

The great graphene race

It’s regularly been said in recent years that there’s a worldwide race going on regarding graphene.

There’s excitement from industrialists, academics, miners and others around the atom-thin layer of carbon, first isolated in 2004 by two Russian-born researchers working at the University of Manchester.

It’s 200 times stronger than steel and boasts other properties including being the most electrically conductive material (at room temperature) known, incredibly flexible yet harder than diamond, nearly transparent, and impermeable to gases and liquids.

It’s of huge interest for purposes ranging from electronics to water purification, but – due to numerous difficulties – nobody has really managed to make graphene very industrially useful yet.

Bar very few examples (notably Head tennis rackets) graphene is not seen in mass-manufactured products.

It’s not for a lack of trying, though.

One of the companies spending the most effort to develop graphene electronics, Samsung, had 405 patents related to the material, according to a UK Intellectual Property Office report from 2013.

By country, Chinese organisations have more patents than any other, with 2,204, according to a report by UK consultancy CambridgeIP (also published last year). The US followed with 1,754 and South Korea 1,160.

A raw count of patents is never a perfect measure, but it gives some indication about who might be interested in the future of the material. 

Vast manufacturing potential

A patent registered in Australia (as well as in the United States, the European Union and Japan) that shows promise involves making a surfactant free dispersion of the material.

Covered in a 2008 paper in Nature Nanotechnology, “Processable aqueous dispersions of graphene nanosheets”, the process has been licensed to Sydney-based start-up NanoCarbon.

“I believe that graphene is going to be an absolutely important component of manufacturing,” the company’s CEO, Chris Gilbey, told Manufacturers’ Monthly.

NanoCarbon aims to initially develop graphene for high barrier films, lithium ion batteries, and water purification purposes. Gilbey believes that there will be a significant need for the nanomaterial, both by itself and as a part of advanced composites.

He admits there are big challenges for NanoCarbon to overcome before it meets its goal of “delivering functionalised SFG graphene at scale” early next year.

However, they have an important and incredibly useful technology on their side, he believes.

“When you can deliver a surfactant-free graphene in aqueous solution you have a platform technology that can deliver an optimum graphene product that can provide very high levels of conductivity as well as strength,” he said.

The company has a novel business model and plans to announce implementation partnerships over the coming months.

Gilbey’s is not the only Australian company that aims to supply graphene in a business-to-business capacity.

Others, such as Valence Industries, plan to manufacture and sell graphene shortly.

As with NanoCarbon, Valence has strong links with a research institution. In Valence’s case, this is The University of Adelaide, to whose Graphene Research Centre Valence has allocated $800,000 over three-and-a-half years.

“The intention there is to make sure, as the globe changes and as new graphene-related products come online, we’re at the forefront of that technological development,” Christopher Darby, the company’s managing director and CEO, told Manufacturers’ Monthly.

“So we want to be able to transform ourselves from a producer of graphite products and in order to do that we have to make sure that we are able to be producing new graphene-related products and apply those very advanced manufacturing skills we already have to produce something in that industry as well.”

Valence, which also mines and manufactures graphite, has a “five- to ten-year program” to build its capability to manufacture graphene, beginning as a provider for universities
later this year.

How is it made?

As its name suggests, graphene is derived from graphite, which is basically pure carbon. Graphite is found in products including lubricants, brake pads, batteries, and, of course, pencils.

The graphene allotrope of carbon is a single layer of atoms, arranged in a hexagonal formation. These layers are clumped on top of each other, held together by weak van der Waals bonds.

The bond is so weak the graphene layers can be pulled apart and isolated using Scotch tape and a large amount of patience, a technique used in labs studying the substance.

The “Scotch Tape” method is how Manchester University physicists Andre Geim and
Konstantin Novoselov first isolated graphene in 2004. Prior to that, it had been known – in theory though not physically – since 1947.

Through repeated cleavage of graphite samples, the pair, and those repeating their method, have been able to isolate tiny, though high-quality samples.

Geim and Novoselov’s efforts won them the Nobel Prize in Physics in 2010.

“The best graphene samples are taken from graphite that way,” explained Professor Michael Fuhrer, an ARC Laureate Fellow at Monash University.

“So mother nature is quite kind in making graphite that’s quite pure, that’s all carbon and doesn’t have a lot of defects in it.”

The samples are excellent for study purposes and elsewhere, though the method is labour-intensive, not scalable, and therefore unsuitable for industrial purposes.

Other, more scalable methods include using a blender – identified this year by researchers at Trinity College Dublin – and chemical vapour deposition (CVD).

CVD involves growing a layer of graphene over catalytic foil heated to around 1,000 degrees Celsius and using methane gas.

It can produce a sample of graphene, in larger samples and more cheaply, though this will be riddled with flaws such as tears and grain boundaries.

“It’s not a single crystal,” Fuhrer explained to Manufacturers’ Monthly.

“There are nucleates on the metal in different places and as these grains grow together it tends to stitch together.”

The grain boundaries create issues of electrical resistivity and tend to be more reactive. Then the metal has to be removed, with further problems resulting.

“If you etch the metal then often you have all these metal ions and solution and some of them will re-deposit on the graphene and you’ll have some leftover metal,” said Fuhrer.

“And the metal’s not exactly flat and so the graphene’s not exactly flat and if you try to transfer it to another substrate you’ll get wrinkles. It can tear. Lots of issues.”

The most scalable approach for large quantities of graphene, said Professor Gordon Wallace, the Executive Research Director at the ARC Centre of Excellence for Electromaterials Science (ACES) at the University of Wollongong, is solution processing.

Wallace was a part of the team (which also included Professor Dan Li from Monash University) that created the surfactant-free process licensed to NanoCarbon.

Solution processing is, “Basically where we’re taking graphite and expanding it, or basically blowing it apart, into individual sheets of graphene oxide, which is then subsequently reduced to graphene,” he told Manufacturers’ Monthly.

“So there’s a number of steps involved in that and you can trace this right back to the actual source of the graphite from the mine.”

Going to the source

Generally, graphite is the source material, and the quality of this has a huge bearing on the quality of the end product.

There are three types graphite is found in: the highly desirable flake form, vein, and amorphous graphite.

The world leader in graphite production is China, followed by India, Brazil and North Korea. Australia is also blessed with graphite deposits, which were last year estimated at 969.59 kilotonnes (Economically Demonstrated Resources). This is all in SA and WA.

Australia’s only currently operating graphite mine, Uley at South Australia, was put in care and maintenance in 1993. Valence Industries, the mine’s owner, listed at the beginning of the year and announced that production of graphite would recommence.

The University of Adelaide has been using graphite from Uley for two years in graphene production.

The high purity of the resource, which has been extracted as 38 per cent graphitic carbon, is highly amenable to that purpose, said Darby.

“It links in with this fantastic material that’s being treated by geological ages that’s very, very pure and very, very unique to this graphite region,” he said.

Working with the university’s team, led by Professor Dusan Losic, Valence hopes to develop intellectual property within the state around graphene.

“We support both pure research, which is fundamentally important to this area, butalso to support the identification of direct product application that can be commercialised and to which we can apply our corporate skill and manufacturing
capabilities and experience to bring to market,” explained Darby.

Valence’s chief agreed that graphene was of significant interest to Australian companies
involved in graphite.

Fellow SA mining company Archer Exploration has also budgeted money, $200,000, to Losic’s university for graphene research.

Another Australian resources junior, Kibaran Resources, has plans that involve graphene.

Kibaran announced a binding agreement with 3D Group on a 3D printing joint venture, 3D Graphtech Industries, in July this year.

 “I think it’s not outside the realms of reality that we can look at getting graphene in the future that could be printed. The commercialisation [potential] of 3D printing with graphene is enormous,” Andrew Spinks, executive director of Kibaran told this magazine.

The joint venture – which is concerned with expanded graphite additive manufacturing
first and graphene second – will source its material from the flake graphite at
Kibaran’s Mahenge and Merelani deposits.

“We believe Tanzania hosts the highest purity graphite globally,” said Spinks.

“And that comes back to the original rock host, the mineralogy, the metamorphic gradient of the deposit.”

3D Graphtech Industries entered an initial research agreement with the CSIRO (with the possibility of continuing research later) in August. It concerns possible market gaps related to expanded graphite and graphene used as 3D printer inks.

What will the killer app be?

There are some ideas about where graphene might be commercially useful, once problems around quality, quantity and price are solved.

Flexible electronic touchscreens seem like a neat match for graphene’s special conductivity and transparency properties, and are expected within the next few years. Samsung, as mentioned earlier, is very much on the task.

“I gather that the issues that they are running into are many of the issues that I just mentioned,” said Fuhrer, who added that ways to impart a charge (doping) while retaining the material’s unique properties still remain challenging.

“There are other applications where they’re a lot more speculative and maybe the devices haven’t been demonstrated yet or maybe there’s some hints of proof of principle but not a really good working device,” he followed.

“I think graphene’s an interesting material and we’re looking for where the interesting and different properties can be applied and I think the answers aren’t quite known yet [laughs].”

Australian universities including Monash and Wollongong are working on applications which show commercial potential.

Wallace’s team at ACES has made progress with futuristic medical processes, including in graphene bio-composites.

“These are composites of graphene with biomaterials that are capable of sustaining and supporting living cell growth – for example in implants for tissue regeneration,” he explained.

“And also those materials and composites are amenable to 3D printing, so we can fabricate the structures in all different shapes and forms.

“The other areas of applications that have benefited from the core fundamental advances are in energy storage, we’re able to make very high surface area electrodes, for batteries and capacitors, that have benefits for conventional energy storage systems, but there are additional benefits with graphene: the mechanical properties of it are such that you can make a range of flexible or wearable energy storage systems for medical applications or preparing autonomous devices.”

Despite all the possibilities, a commercially successful “killer app” around graphene has yet to be seen.

In a dollars and cents sense, offered Gilbey, “At this point in time graphene is all promise and no realisation.”

Challenges

The challenges are of course many, and several have been described above.

Dealing with anything that exists on an atomic scale is going to be a sensitive operation. There is a lot of room for improvement.

“Where a lot of the optimisation has to occur is in matching the chemistries to the source of the graphite,” explained Wallace.

And then there are still considerations to be worked out around transporting the material. Trucking dispersions carrying a few per cent worth of graphene around the  country does not seem optimal.

NanoCarbon is still considering a range of options for where it might set up its factory, and where it might be best placed to serve an advanced manufacturing customer base.

Companies who will want graphene will not simply want a one-size-fits all approach, either, and there will be engineering solutions needed from any provider of graphene.

“[Will] customers want to add new conductivity to the composite material, do they want to add strength to it? Do they want to add some impermeability to gases to it? What is it that’s going to be required?” asked Gilbey.

Also, vials and bags of graphene oxide can easily be purchased on eBay. But does this mean that they would be useful to a manufacturer wanting to integrate them into their products? Maybe not.

“You get the graphene and what does that mean?” he asked rhetorically.

“To my way of thinking it’s kind of like if you bought alcohol and you said, ‘I’m buying alcohol, and now from my alcohol, my expectation is to get a Chateau Lafite.’ Well it ain’t gonna happen, baby!

“You can put alcohol in water and add red ink and it’s not going to be Chateau Lafite. This is about horses for courses.”

At Valence, their relationship with the University of Adelaide’s engineering school will be of great benefit, said Darby, as would Valence’s quality control capabilities.

“That is one of the challenges that have been found globally in terms of delivering graphene for even current manufacturing purposes,” he said.

“That there are many people saying they can do this and spruiking the idea but it’s not necessarily true.”

Potential for Australia

The global race to make something out of graphene is well and truly on.

Consider that a year ago the European Commission announced a billion Euros to fund the Graphene Flagship initiative: a decade worth of graphene R&D involving 17 countries and 76 academic and industrial research groups. Clearly this is a major endorsement of the possibilities the tricky material might offer.

Australia has a chance to take advantage of the as-yet untapped potential too, says Wallace, as well as the skills and resources needed to do it properly.

“We do have the chemistry and the materials science expertise and we’re fortunate to have, at the other end of that, people that are capable of commercialising devices and structures in the composites area for engineering applications right through to the energy and the medical bionics areas,” he said.

Gilbey believes that developing technology around graphene and introducing this into industry will be critical for advanced manufacturing.

“Advanced manufacturing is about novel materials, I think,” he said.

“So I don’t see how you can really develop the potential of advanced manufacturing [without it], and I’m thinking in terms of additive manufacturing as well as the use of materials that provide new kinds of functionality to those things that we’re quite familiar with.”

There is reason to have some hope, believes Wallace, but the window of opportunity is closing quickly.

According to the electromaterials expert, the future belongs to those who can best handle the task of aligning a pipeline including the mines, the researchers, and those with the commercial nous.

It won’t be easy, he concedes.

“I think in Australia we have an opportunity to do it, and there are graphite mines and there’s interest in opening up other graphite mines,” he said.

“Our challenge will be can we be the most nimble team on the planet in terms of aligning those skills and getting it out of the ground and into devices and structures in a manner which is economical but retains all of these wonderful properties of the nanostructured components that we find in graphene in the nano world.”

 

Slider and top image:

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Story images (all supplied) in order

NanoCarbon graphene bottle

Processed graphite from Uley mine

Uley processing operations

Professor Gordon Wallace

Chris Gilbey