The Wonder Material Graphene From Trash

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A recent breakthrough in the research revealed the process of making the wonder material graphene from the trash.

Graphene is cool stuff. The single-atom-thick layer of carbon has a number of properties that make it almost endlessly useful. Because of all the neat tricks, it can do, it’s popularly dubbed a “wonder material”

But over a decade and a half, after it was first isolated, the only thing I’m wondering is: where it is? Turns out the stuff is really hard to make in useful quantities, but a recent breakthrough from researchers at Rice University promises to make large amounts of graphene in a flash from your trash.

Graphene looks like this. Anyway, it’s not much to look at—it kind of resembles chicken wire. But this honeycomb lattice of carbon can do some amazing things. It is one of the thinnest, strongest, and most conductive materials we have ever discovered. This strength can be used to reinforce other materials.

Its amazing conductivity could help us make energy-dense batteries or efficient heat sinks. Its flexibility could make wearable electronics and bendable displays.

Ironic, given that it was first extracted by adding a piece of sticky tape as you might have in your home to a block of graphite and peeling it off, then re-sticking and peeling the tape off until you have thin flakes left behind. It’s like it’s taunting us.

Also Read: Engineering Bionic Mushrooms with Graphene Nanoribbons

But there’s a reason we don’t have armies of people just peeling tape apart. The graphene produced by this technique is still a few layers thick and we are after that single-atom-thick goodness. As of right now, the prevailing methods to achieve that usually involve assembling it on sheets of copper, than using plastics and chemicals to get it off.

But the process is not environment-friendly and it’s slow and expensive. A piece of 60mm x 40 mm monolayer graphene on copper will cost you about $172.

But what if we’re overthinking this? What if we could just take any old carbon source and zap it to make graphene? As far as I can tell, that’s basically the line of thinking the researchers from Rice University followed.

The Wonder Material Graphene From Trash
Credit: Nature
The Wonder Material Graphene From Trash. Rice researchers made graphene on different scales using flash Joule heating.

The method they have developed involves charging high-voltage capacitors with electricity, then releasing them all at once into almost any substance containing carbon.

The current passes through the target material, heating it to over 3,000 Kelvin and breaking every carbon-to-carbon bond in the process. The non-carbon elements sublime out, while the carbon atoms rearrange themselves as graphene.

Also Read: What is Neuromorphic Computing?

Excess energy is dispersed as light, so researchers dubbed the product “flash graphene.” The change can take as little as ten milliseconds. Not only does this produce a gram of graphene quickly and cheaply; it also makes a particular kind of graphene called turbostratic graphene.

Unlike A-B stacked graphene, which has orderly layers that are hard to pry apart, the layers of turbostratic graphene have no ordered alignment. This means they can be easily separated using

solvents or inside composite materials.

Now, this process doesn’t make large sheets of graphene, just small flakes. So, it may not be the breakthrough that leads to flexible screens you can put on a T-shirt. But it still has some very useful—albeit less flashy—applications.

The researchers envision flash graphene being added to concrete and estimate that just a fraction of a percent of graphene added in could boost cement’s strength by 35%. That translates to less building material needed, saving costs and lessening the environmental impact.

Also Read: The need for Quantum Computing

Flash graphene could be an ecological double win because it can be made with recycled plastic or food waste, or it could be an alternative use for cheap coal that doesn’t involve burning it and releasing CO2. The Department of Energy thinks turning coal into graphene looks promising and is funding the research with the goal of producing a kilogram of flash graphene a day within two years.

We are all clamoring for graphene to take the world by storm, but the reality is that it’ll take incremental steps like this to bring this wonder material into our daily lives. It’s already showing up in places that are hard to spot, like inside headphones and the coating of motorcycle helmets. Now thanks to this new work, it may soon show up in our buildings, too. And the only way you might be able to tell is if you measured the thickness of the walls or noticed there was suddenly a lot less plastic and banana peels lying around.

One of the lead researchers from Rice, James Tour, started experimenting with making graphene out of odd sources because of a bet in 2011 when a colleague challenged him to make it out of, among other things, cockroaches and dog poop.

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