Graphene has long been known as something of a wonder-material, given its high durability and the fact that it is both the thinnest and the strongest material, consisting of a single layer of carbon atoms that is pliable and highly conductive. Such properties means it provides a more efficient alternative to current battery types – charging at a much faster rate than its traditional counterparts. Despite its potential, the material has not yet been developed for mass commercialisation due to the difficulty in producing it at quantity in an environmentally and economically sustainable way. Now, a team at Kansas State University think they may have cracked the code.
The research team is led by the University’s assistant professor of industrial and manufacturing systems engineering Suprem Das, in collaboration with Christopher Sorensen, university distinguished professor of physics. Together, they are looking into ways of producing graphene-based nano-inks to create flexible, printable electronics that could prove a significant milestone in renewable technology production. From electric vehicle batteries to solar panels, the tech’s application is vast, and would make manufacturing far more accessible. We took a closer look at the university’s process, and the role it could play in a renewable future.
How does it work?
Speaking with Das, he says the team’s method seeks to address the existing problem of producing graphene on an industrial scale.
“Graphene is not easy to source, and in a typical chemical vapor deposition process that produces a relatively larger area of graphene, high scale production of it can still be challenging,” he says. “The process works at around 1000 degrees centigrade, so if you’re trying to upscale the technology, your process should be compatible with high temperature.”
The Kansas team instead uses a ‘detonation process’ to create the graphene, which is then adapted to make the ink.
“My colleague Christopher Sorensen synthesises graphene from hydrocarbons using a detonation process – combining hydrocarbons with oxygen and detonating the precursors within a chamber to form graphene,” says Das. “I then take this graphene powder and turn it into an ink. This uses a proprietary method engineering graphene’s particle size and exploiting surfactant molecules to keep them floating in a solvent while not agglomerating the suspended particles to settle down. Our inks have been shown stable in the suspension for several months until we finish using it.”
Once the ink is made, it can then be deployed in regular inkjet printers to make small-scale, flexible electronics.
“The ink can be used in a variety of applications, including an inkjet printer to print components like an electric circuit, an energy storage device, etc,” says Das. “Once you have the right ink you can make flexible electronics, flexible power sources, transparent conductors for solar cells – there are so many possibilities”
The team has thus far manufactured supercapacitors using the ink, and have tested the products for 10,000 cycles of charging and discharging, with results showing the product is successful. Ensuring consistency in the materials is essential, though Das also says ensuring the process is environmentally friendly has also been a crucial factor for the team, with Sorensen engineering the process to ensure no byproducts are left behind – all material is used to make the product.
“We have to make sure that our production method is very very reliable – we need to ensure it produces the same quality of product every time, and we have to ensure it’s environmentally safe – leaving no waste products behind,” he says. “We’ll be keeping all of these things in mind as we work to scale up.”
The future of graphene
“Recently there has been a push for mass-scale production of graphene, to find ways to master production of graphene and hence subsequent application,” Das says. “We are working to upscale our ink synthesis process to an industrial level. We are already in the process of scaling it up to make gallons.”
While the work was originally funded by the US National Science Foundation, the project has already started to see interest from private organisations, with some gearing up to license the technology. Das predicts that interest in the material is only going to rise as demand for renewable energy also increases.
“While this technology of making graphene nano-ink is still in its early stages, using graphene in this way is becoming much more important globally,” he says. “It’s going to become much more amplified in the coming years in the wake of areas such as printed electronics and wearable electronics to give you a few examples.”
The team at Kansas State is not the only one looking into graphene applications, with Swiss researchers at the Swiss Nanoscience Institute and Department of Physics at the University of Basel examining how the material’s properties change when stretched – research that they hope will pave the way for developing new types of electronic components.
In order to test graphene’s electronic properties, the team mechanically stretched it over a specially made rack.
“Stretching the graphene allowed us to specifically change the distance between the carbon atoms, and thus their binding energy,” said experiment supervisor Dr. Andreas Baumgartner in a press release.
With projects such as these underway, graphene’s role in the green revolution seems to be on the rise – and we may well be set to see a lot more of this material in the future. While more research is needed before we can expect to see it produced on a commercial scale, provided projects stay environmentally sound graphene could be instrumental in helping us to realise our renewable energy targets as we find novel ways to make and apply this super-material.