Turning Garbage Into The World’s Strongest Material: Graphene

Since it was first isolated in 2004 by Andre Geim and Kostya Novoselov at the University of Manchester, graphene has excited scientists because of its many unique properties. As a one atom thick sheet of carbon, it has the highest strength to weight ratio, is the best known conductor of heat, conducts electricity better than copper, is virtually transparent yet can still be used in solar panels, can be stretched up to 20%, is bendable, among may other exciting qualities.

Despite being so revolutionary, scientists have had trouble getting graphene out of the lab and into the real world. Producing it on a large scale has proven more difficult than they hoped, as current methods are expensive and slow. For example, mechanical exfoliation removes one layer of graphene from graphite with specialized tapes, much like the original researchers did with Scotch Tape. Chemical exfoliation uses specialized solvents to rearrange carbon atoms in graphite and then remove individual layers of graphene through rapid heating or sound waves. Both of these, as well as other methods, are highly specialized and can produce only a few flakes at a time.

Fortunately, a team of chemists from Rice University just published a paper explaining how they can take any carbon rich substance and turn it into graphene. They claim it can be done with “coal, petroleum coke, biochar, carbon black, discarded food, rubber tyres and mixed plastic waste.” They hope that they will be able to produce more than 2 kilograms of graphene a day with this method.

Flash Graphene

They call it “flash graphene” after how quick the process happens. The researchers apply an electric current to bring a carbon rich substance to over 3,000 Kelvin in only a few milliseconds, a technique known as Joule heating. At temperatures this high, the constituent molecules of the substance break down and vaporize, freeing the carbon to bond with itself. Everything else is emitted as vapor, which can be captured and reused.

The challenge, though, is finding the right temperature and the right timing. The process is essentially recreating the phenomenon of carbon becoming graphene and then becoming graphite, its natural ground state, although the intense heat makes it happen far quicker. If the temperature is too high or the process goes too long, then the carbon atoms will reach this ground state, but, if the process is calibrated correctly, it can be interrupted at the graphene stage.

Not only is this process near instantaneous, it offers a myriad of other benefits. For example, the carbon rich substance does not need to be purified by solvents, reactive gases, or anything else that are expensive and potentially harmful. This means that old banana peel is ready to be used as is.

“Flash graphene” also produces a purer and easier to handle form. Other methods produce graphene that is rife with defects and difficult to separate layers. This method produces graphene that is 99% pure and has turbostratic stacking, meaning the layers are misaligned, allowing researchers to separate them with little effort.

A World In Need

The planet is in the throws of the next mass extinction, which has largely been due to human activity. Air pollution kills millions of people each year, and microplastic is being found virtually everywhere. Fortunately, “flash graphene” offers a way to productively use plastic waste, coal and oil byproducts, food waste, etc. If used on a large scale, “flash graphene” would certainly reduce the negative impact humanity has on the planet.

Furthermore, scientists have already found several uses for graphene in sustainable engineering. For example, adding flakes of graphene to concrete, plastics, various metals, etc. makes a composite material that is far stronger and durable. This study found graphene-concrete composites result in an “increase of up to 146% in the compressive and 79.5% in the flexural strength.” Therefore, this should result in concrete structures lasting longer, cutting into air pollution, as concrete is responsible for 8% of human carbon dioxide emissions.

Graphene can also be used to make transparent and flexible solar panels, much better batteries and supercapacitors to store both residential and grid-level renewable energy, anti-corrosive coatings to prolong the life of buildings, cars, etc., much more sensitive and customizable water filters and air filters, among many others.

Because of its many revolutionary applications, graphene has been called a miracle material for years, but commercial adoption has been slow due to laborious and expensive production. However, the “flash graphene” technique discovered by chemists at Rice University, led by James Tour, will bring graphene into the mainstream, helping reverse and prevent damage to the environment.

If you enjoyed the article, please consider donating!