| PhD student Benjamin Mueller holds a solution of graphene oxide solut... PhD student Benjamin Mueller holds a solution of graphene oxide solution watched on by fellow research team members Dr Dan Li and Professor Gordon Wallace | 
| A molecular model of a graphene sheet. Courtesy Mike Kuiper (VPAC) A molecular model of a graphene sheet. Courtesy Mike Kuiper (VPAC) |
Discovery promises major advances in energy conversion and storage
29 Jan 2008 | Bernie Goldie
University of Wollongong scientists have made an exciting discovery that enables processing and fabrication of an abundant form of carbon with extraordinary properties.
Results of the discovery were released in the prestigious international journal, Nature (Nanotechnology), yesterday Monday January 28 (AEST).
Director of the ARC Centre of Excellence for Electromaterials Science (ACES), Professor Gordon Wallace, said results already indicated that the discovery would lead to advances in energy conversion (new transparent electrodes for solar cells) , energy storage (new electrodes for batteries -- especially flexible batteries) and as new electrodes in medical bionics.
The discovery was led by QE2 Fellow in ACES/Intelligent Polymer Research Institute, Dr Dan Li. Other collaborators included recent Fulbright Fellow at the University of Wollongong, Professor Ric Kanar, who hails from UCLA in the United States, and University of Wollongong PhD student, Benjamin Mueller.
The Nature (Nanotechnology) paper is titled, ‘Processable aqueous dispersions of graphene nanosheets’. Graphene — a carbon-based nanomaterial known for its unique electronic, thermal and mechanical properties — can form stable dispersions in water without the need for additional chemical stabilisers. The researchers’ findings will have practical implications for the development of coatings to reduce static build-up on materials.
Graphene is the name given to the individual sheets of carbon, just one atom thick, that stack together to form graphite. Keeping graphene sheets separate from one another is a difficult task because they tend to stick together, forming larger structures that are not particularly useful. However, now the UOW team, using a sequence of chemical reactions, has shown how aqueous dispersions of well-separated graphene sheets can be made from graphite — an abundant and inexpensive starting material.
Rather than relying on either polymer or surfactant stabilisers, their approach maximises the electrostatic charge on the graphene sheets, ensuring that they repel one another instead of clumping together.
Professor Wallace said that this low-cost approach offers the potential for large-scale production of stable graphene colloids that can be processed using well-established solution-based techniques — such as filtration or spraying — to make conductive films.
“In addition to antistatic coatings, these materials are expected to have applications in flexible transparent electronics, high-performance composites and nanomedicine,” he said.
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