The ‘wonder material’ graphene can be made using a kitchen blender, a mobile phone and a newspaper

Conor Boland, Dublin City University

There is something slightly ridiculous about using a kitchen blender to make graphene. This is, after all, the “wonder material” associated with futuristic technologies. You might reasonably expect its production to involve equally futuristic equipment. Often, it does.

Producing graphene in liquid form can rely on purified graphite (better known to many as the “lead” in pencils), specialist solvents or additives, ultrapure water and carefully controlled processing. Our latest research asked what happens if you try to make it using things you’d find in your household.

Could you start with graphite found in electronic waste, use old newspaper to help hold it in a liquid, mix everything in ordinary tap water and still end up with useful graphene?

Graphene is many times stronger than steel, yet it weighs less than paper or aluminium. It is also an exceptional conductor of electricity. Since its discovery just over 20 years ago, it has found uses in power banks and batteries, in medical sensors and even to make stronger concrete. Many other practical applications beckon for this incredible material.

Inside phones, laptops and other electronic devices are thin sheets of graphite used to spread heat away from components so they don’t overheat. When a device reaches the end of its life, that graphite generally follows suit and ends up as electronic waste. Chemically, however, it’s still graphite and has the potential to become its wondrous cousin, graphene.

The scale of the electronic waste problem is enormous. Around 62 million tonnes were generated worldwide in 2022, yet only 22.3% was documented as being properly collected and recycled. Valuable metals understandably attract much of the attention, but electronics also contain less glamorous materials that could have another life.

Could these graphite heat spreaders be one of them? Graphite is essentially a large number of sheets of the element carbon stacked on top of one another, like a deck of cards. These sheets are generally one atom thick. Each individual sheet of carbon is graphene.

The challenge is separating those sheets without destroying them. We used an Irish-pioneered process called liquid-phase exfoliation. We put graphite into a liquid and applied enough energy to break the stacked layers apart.

From this liquid form, the graphene can be turned into coatings, ink, membranes and composites with many potential applications.

Low-tech solution

Instead of a fancy processor, we used a simple kitchen blender, while a kitchen sieve removed lumps that hadn’t been properly broken down. Making graphene, however, is only half the problem. Once separated, the sheets have an annoying habit of sticking back together again.

Researchers normally prevent this using carefully chosen solvents or stabilising chemicals. But we wondered whether untreated tap water and waste newspaper could do part of that job instead.

Newspaper is rich in cellulose, the structural material found in plant fibre. We washed and softened old newspaper in tap water and blended it into a fibre-rich liquid. When graphite was processed in this mixture, the newspaper-derived material acted as a temporary barrier between the newly separated graphene sheets.

It wasn’t perfect, but that was never really the point. Without the newspaper-derived material, the processed material settled out of the water within minutes. With it, the solution remained usable for several hours and could be mixed again with a simple shake. The result was still graphene.

Of course, a black liquid from a blender isn’t proof of that. We still needed sophisticated laboratory equipment at Dublin City University to confirm what we’d made. But almost none of that sophistication was needed to actually produce it – and that’s perhaps the more interesting part of the story.

Making graphene easily

In previous work, we showed that graphene could be made using pencil lead, tap water, soap, kitchen appliances and even coffee filters. That work asked whether nanoscience really has to begin in an expensive specialist laboratory. Here, we went a step further: could the ingredients themselves come from waste?

In a well-equipped university, it’s easy to take specialist chemicals, purified water and expensive equipment for granted. But research groups in lower-income countries can face tighter budgets, difficult supply chains and long waits for specialist materials. Schools and citizen-science projects face an even bigger barrier: simply getting started can be expensive.

Our approach turns that problem around. Rather than asking how sophisticated graphene production can become, we asked how much sophistication we could remove before it stopped working. The ingredients aren’t exotic: newspaper, tap water and graphite already sit inside most homes.

For most of our experiments, we used a commercial version of the graphite heat-spreading material because a single phone contains very little of it. But we also took apart a discarded smartphone and recovered some of its graphite. There wasn’t enough for the full study, but there was enough to show that material taken directly from real electronic waste could also be broken down into much thinner carbon sheets.

That opens up a different way of thinking about where research can happen. A school, community laboratory or small research group could potentially carry out the processing locally, then work with a university or shared facility when advanced measurements are needed. Expensive equipment becomes something used to verify the result, rather than the price of admission to the experiment.

So the point isn’t that we’ve found the world’s best way to make graphene. We certainly haven’t. A discarded phone, yesterday’s newspaper, tap water and a blender won’t replace a graphene factory. But they might make graphene research a little less exclusive, while giving two ordinary waste streams a chance at a second life.

There’s a nice irony in that. We needed sophisticated scientific equipment to prove that we’d made graphene, but actually making it was the accessible bit.

This article is republished from The Conversation under a Creative Commons license. Read the original article.