Professor Dan Li& grapheme

BBR Exclusive Memorandum of Understanding signed with Monash University to develop a commercialisation plan for the intellectual property invented by leading Australian graphene expert Professor Dan Li.

Breaking news.

A major technical obstacle has been jumped in science's quest to deliver revolutionary grapheme technologies to industry and medicine.
Dark grey, a little greasy to the touch, graphite is neither pretty nor particularly useful. Most deposits around the world sit largely untouched, although it is used in a variety of ways in the steel industry, in batteries and lubricants, and of course as "lead" in pencils.
But a few years ago, this poorest of ores revealed a secret. At the molecular level it is a unique two-dimensional molecule: an electrically conductive lattice-like layer just one carbon atom thick. In this state it is called graphene, and an intensifying global research effort into this attribute is putting graphite at the brink of becoming one of the most valued ores ever mined.

It has usually cautious physicists and chemists itching with excitement, mesmerised by the possibilities starting to take shape – from flexible electronics embedded into clothing, to biomedicine (imagine synthetic nerve cells), vastly superior forms of energy storage (tiny but immensely powerful batteries) and an array of new materials that could make many of today's common metals and polymers redundant.
"We have opened a door and found a vast room with no walls or ceiling. It is potentially limitless," says one of the early graphene research pioneers, Professor Dan Li at Monash University's Department of Materials Engineering.
Professor Li began searching for a functional platform for new graphene-based technologies in 2006, barely two years after a single layer of graphene was first separated from graphite. This was done by two curious University of Manchester physicists, Professor Andre Geim and Professor Konstantin Novoselov, who simply used sticky tape to peel off micro flakes. It started as a bit of fun, but turned serious when they realised that by repeatedly peeling off further layers from the original flake they were able to get down to the thinnest possible layer, just one carbon atom thick.
For many scientists this discovery is up there with penicillin for the opportunity that has been opened for graphene technologies to impact on just about every aspect of human activity and endeavour. Certainly few were surprised when the pair was awarded the 2010 Nobel Prize in Physics.
Functionality challenge

However, while scientists can see extraordinary potential for graphene's properties – from its electrical conductivity to the creation of new materials, including biomaterials, that would be lighter, stronger and less energy-demanding than anything currently in use – the stumbling block has been to get graphene into a useable form.
Being only one atom thick, the two-dimensional graphene layers pack tightly like the pages of a book. For it to be functional, ions or other molecules need to be able to engage with the flat molecular surface area between each layer.
So a challenge has been to find ways to take the graphene sheets apart and reassemble them into functional macro forms in which the full potential of the individual sheets can be accessed.
This is where Professor Li's research is opening the next tantalising chapter in the graphene story. He has invented a cost-effective and scalable way to split graphite into microscopic graphene sheets and dissolve them in water. From this he has developed two new graphene technology platforms – the starting points for developing commercial applications. One is a graphene gel that works as a supercapacitor electrode, and the second is a 3-D porous graphene foam.
We have opened a door and found a vast room with no walls or ceiling. It is potentially limitless.
– Professor Dan Li
The graphene gel provides the same functionality as porous carbon – a material currently sourced from coconut husks for use in supercapacitors and other energy-conversion and storage technologies – but with vastly enhanced performance.
Professor Li's research has already produced two papers in the journal Science plus six pending patents. These are for processes developed for suspending graphene in a water solution at room temperature (a major breakthrough because graphene is otherwise water-repellent) for the development of the gel and for the even more functional 3-D foam.
First stable platforms

These are remarkable achievements that provide some of the first stable platforms from which new graphene-based technologies can now be developed.
Professor Li has already taken the first steps towards a commercial application by developing a high-performance graphene-based energy-storage device. Since its unveiling in Science last August the device has been touted as a breakthrough in the field of supercapacitors.
Current supercapacitors use activated porous carbon impregnated with a liquid electrolyte to carry the electrical charge. The drawback is a low energy density (energy storage-to-volume ratio) of just five to eight watt-hours per litre. But by replacing the porous carbon with a multi-layered graphene gel film, Professor Li's team has created a compact supercapacitor with an energy density of 60 watt-hours per litre. Supercapacitors have an expanding range of applications as their capabilities increase, from powering computer memory backup to powering electric vehicles.
Professor Dan Li says his team has a platform to move from the laboratory to commercial developments. Photo: Brad Collis
The gel film is made by dissolving graphene in a water-based solution to create a graphene "ink", which is then filtered (not dissimilar to traditional paper-making).
To make a graphene electrode from this gel, Professor Li's team used liquid electrolytes to control the spacing between the graphene sheets. In this way the liquid electrolyte plays a dual role: maintaining a space between the graphene sheets and conducting electricity.
In a parallel development, Professor Li's team has also been able to give graphene a more functional 3-D form by engineering it into an elastic graphene foam. This is made by a process Professor Li calls "freeze casting". As the solution's ice crystals form, they exert enough pressure to distort the flat structure of the graphene sheets and, significantly, the effect is irreversible. The graphene sheets stay separated after the liquid thaws into a foam that has a similar cellular structure to cork.
The graphene blocks produced by this revolutionary process are extremely light, able to support more than 50,000 times their own weight, are efficient conductors of electricity and are highly elastic.
"We've been able to preserve the extraordinary qualities of graphene in an elastic 3-D form. This paves the way for the anticipated uses that people have for graphene, from aerospace materials to tissue engineering," Professor Li says. "We have a platform from which to move us from the laboratory to commercial developments."
New energy

One of the leading researchers internationally in the use of graphene for energy applications, Professor Richard Kaner from the University of California, Los Angeles (UCLA), says Professor Li's high surface area developments open up exciting new energy applications.
"The beauty of Dan's gel development is that it is scalable so could be used to build very large supercapacitors of high-energy density," he says.
Professor Kaner, who is Distinguished Professor of Chemistry and Distinguished Professor of Materials Science and Engineering at UCLA, is also researching graphene energy applications, but has taken a different path. "My research is investigating light-scribed graphene. We hit graphite oxide with a powerful light source to convert it to a porous carbon network. Our approach suits the development of micro supercapacitors. Dan has opened up a more macro-scale platform."
Professor Li likens his developments to having invented bricks, and now it is time to bring in architects and builders to create new technologies based on his platforms.
"The opportunities now are limitless," he says.
"These graphene molecules bring a whole new capability to nanotechnology and materials science, and this includes new-generation energy storage and harvesting devices, bio-compatible materials able to work in the human body, separation membranes for water purification, and strong and lightweight composite materials for aerospace."
Professor Li attributes his success in tackling the graphene separation issue to his decision to take a chemistry (his primary academic background) rather than a physics approach. This, he says, is how he found a way to make the graphite dissolvable in water, which was the starting point for the graphene gel and foam.
"These are very exciting because they are bridges between concepts and actual new technologies

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