A revolutionary machine that can unboil an egg is being used to develop graphene purification technology.
Researchers from Flinders University in South Australia along with Western Australian company First Graphite Ltd will use the dynamic Vortex Fluidic Device (VFD) to produce high-quality graphene for industrial use.
Graphene is the building block of graphite and is one of the most sought after materials in the world because of its robust nature. More than a million metric tons of graphite are mined globally each year. It is 200 times stronger than steel but remains flexible and impermeable, making it ideal for the development of a range of modern technology such as lithium-ion batteries, sensors and transparent-conducting electrodes for flexible solar cells.
Based on previous graphite research involving the VFD, First Graphite plans to scale up the process to a commercial level with the potential of delivering high-value carbon materials to global markets. First Graphite Managing Director Craig McGuckin says the potential uses of graphene cover a vast range of industries and he believed the material would eventually be used in most modern technology.
“What is required is creating high quality graphene from graphite, doing so quickly and efficiently and that is what we are trying to take up now,” says McGuckin. “We see the VFD partnering with our own processes to assist greatly in creating different types of graphene for different uses.”
In 2015, Flinders University scientists were awarded an Ig Nobel Award for creating the Vortex Fluidic Device and using it to unboil an egg. The device has also been used to slice carbon nanotubes accurately to an average length of 170 nanometres using only water, a solvent and a laser. It is now being tested to prove its potential as a commercially viable graphene producer.
Colin Raston, the VFD’s creator and Professor of Clean Technology at Flinders University, explains that graphite is made up of multiple crystalline layers of graphene that can be stripped off by his machine. He says conventional methods use harsh chemicals, which generate defects and change the properties of the graphite.
“You can’t keep making graphene the same way anymore, you need to make it better and address the waste issues as well,” says Raston. “Given the capabilities of the VFD we are going to explore the operating parameters of producing graphite. An environmentally safe process of producing the graphene opens up more applications for it – it also makes it a cheaper option because you eliminate waste.”
The VFD that will be used to manufacture the graphene sheets is a suitcase-sized piece of equipment that applies very high sheer forces to liquids fed into the system through spinning a tube at high velocity.
“Graphite is a well-known solid lubricant because the sheets slip relative to each other,” Raston says. “The VFD would cut through the graphite with precision and could be scaled up by aligning a row of machines parallel to each other or creating a larger device.”
First Graphite aims to develop an underground mining operation in Sri Lanka to extract high-grade, crystalline vein graphite and plans to use the VFD to help extract high-value graphene. Graphite has seen a resurgence in price in recent times due to increased demand from applications such as lithium-ion battery technology for electric cars, but could now see itself replaced by graphene.
Graphene has the largest volume to surface area ratio of any material, weighing in at about 0.77 milligrams per square metre and capable of stretching up to 20% of its initial length. It is an isotropic heat conductor and has up to five times the conductivity of graphite. It also has the highest recorded electrical current density, about one million times that of copper.