Producing high-quality graphene in large quantities

An Irish–UK team based at Trinity College Dublin has demonstrated a new approach to producing large volumes of high-quality graphene using a commercial blender, which could mark a significant breakthrough in the deployment of the so-called ‘wonder’ material in a range of consumer and industrial products.

Much time and resources has gone towards the quest of producing defect-free graphene in sufficiently large amounts since it was discovered in 2010 by Manchester University researchers Andre Geim and Konstantin Novoselov, who shared the Nobel Prize in Physics for their achievement. Although graphene is expected to find uses in a whole range of applications, such as low-cost, foldable electronic screens, the next generation of food packaging, tough plastics and in protective coatings, it is currently produced through the process of chemical vapor deposition which can only able to make meter-scale sheets of the material that also contain impurities.

The new study which was led by Jonathan Coleman, Professor of Chemical Physics at Trinity College, and published in the journal Nature Materials [Paton et al. Nat. Mater. (2014) DOI: 10.1038/nmat3944], is the first to demonstrate how to successfully develop such large-scale production of good graphene materials using a combination of lab-grade surfactant and a mixer. The commercial blender was able to create enough shearing force from its rapid rotation in conjunction with high-shear mixers to separate the layers of graphene into graphite flakes without affecting its two-dimensional structure.

“It has huge potential to change everyday products that we are familiar with – computer screens, batteries, beer bottles/food packaging. But it is needed in very large quantities for these industries to use. That’s what we have done – make really high quality graphene that could transform everyday materials.”Jonathan Coleman.

The well-dispersed solutions were produced from graphite powder, before the team deployed the centrifuge to separate the flakes out of the resulting black liquid. Despite the exfoliated graphite flakes still not being of sufficient quality for high-performance electronics, the team did manage to successfully test their performance as a conducting material in applications such as composites and coatings.

Working with UK company Thomas Swan Ltd, the researchers showed that the high-shear mixing of graphite in stabilizing liquids can result in large-scale exfoliation to offer viable dispersions of graphene nanosheets. This straightforward approach was based on making high-quality graphene-containing liquids in quantities of a few 100 milliliters but that the process could also be scaled up to produce hundreds of liters. They have already patented a couple of new products from the research and hope to have the capability of producing a kilo of graphene every day by the end of 2014, which would be sold either as a dried powder or a liquid spray.