Researchers at AMBER, the SFI Research Centre for Advanced Materials and BioEngineering Research and Trinity’s School of Physics, alongside colleagues in researchers at the Cambridge Graphene Centre, University of Cambridge, Newcastle University, the University of Stavanger, Norway today announced the development of next generation low-cost scalable production method for graphene in the Nature journal 2D Materials and Applications. Their process could substantially reduce graphene production costs to ~£20 per litre once scaled due to carbon's elemental abundance and produce multi-tonne quantities if successfully commercialised, far exceeding the current global graphene supply ~ 1 kilotonne. These cheap, scaleable production methods are needed to accelerate the adoption of graphene to industry and encourage graphene manufacture that has previously been hampered by high capital equipment and labour costs. 

Graphene and other atomically thin '2D materials' are expected to find major commercial applications in the coming years due to their unique electrical, optical, mechanical, chemical and thermal properties. Graphene can be used as a barrier material for anti-corrosion, an additive for mechanical reinforcement in polymers, or as a conductive material in sensors. These applications will require  high-quality defect free graphene  supplied in vast quantitates far - exceeding current supply – and at low cost.

The teams approach is based on the process of exfoliation of graphite – an abundant bulk material commonly found in pencils – that is made up of layers of graphene. They have found a process by engineering the fluid dynamics to exfoliate graphene flakes from graphite with minimal defects due to the reduced turbulence of the system; such high-quality graphene is necessary for applications that require high conductivity, such as the electronics or energy storage industry. The new method not only produces high-quality graphene ‘flakes’ suitable for industrial commercialisation but is also a low-cost, in-line, and an enclosed process that is semi-automated, recycles unused graphite – making it super efficient.

Building on this approach the team created high-quality graphene inks and used household ink-jet printers to make conductive interconnects and lithium-ion battery anode composites that could potentially connect a battery to a textile sensor which could then be used to measure vital signs in the wearable health industry, amongst other applications. Given the applications in wearable electronics, textile electronics, composites and printed interconnects that could involve human contact with high concentrations of graphene the team worked with colleagues at the University of Stavanger, Norway, to determine the biocompatibility of the graphene inks. Repeated measurements showed no acute toxicity found when using the highest concentration of graphene in 48h cell culture treatments.

Lead author on the study Dr Tian Carey suggests this is just to start of investigations: “We have demonstrated energy storage composites and printed electronic components in our work however, there are many more applications that could be achieved with the graphene inks, such as reinforcement composites or printed sensors. Also graphene is just one example of a conductive 2D material; there are hundreds other lesser-known 2D materials which have different but complementary electronic behaviour that we can apply this process to and create a suite of inks with different but complementary properties”.

Commenting on his team and collaborators success, Prof Jonathon Coleman added: “About ten years ago, I pioneered a simple method of making graphene from graphite through exfoliation in a household kitchen blender that has since been scaled and commercialised. In this work, we have adapted the method further for industrial application and shown we can produce high-quality graphene at low cost in a highly efficient manner that is easily scalable”.

The study was funded by Science Foundation Ireland, a Marie Skłodowska-Curie Action Individual fellowship “MOVE” and supported by the Engineering and Physical Sciences Research Council (EPSRC), in the UK.