It’s strong, it’s flexible, and it’s here. After a long time cooking in the labs, the first graphene-based products are beginning to trickle out into the world of smartphones, wearables, batteries, virtual reality, sports equipment, super-capacitors and supercars.
It’s a material that some believe has been coerced from abandoned space ships, left on earth by distant races years ago. While that’s a little unlikely, the power of this super thin, strong, conductive and all-round amazing material is deserving of such a conspiracy.
It’s been over 60 years coming as scientists and manufacturers alike have struggled to harness the power of this awesome material – but it’s closing in on revolutionising so many things we’re using day to day.
3D camera sensors
If you’ve read up on graphene, you may have heard eye-openingly optimistic reports of a graphene camera that’s 1000x more sensitive to light than the ones we have today, conjuring visions of pixel-perfect night shots.
While you won’t want to get your hopes up for that just yet, a more recent project from the University of Michigan deserves a closer look.
It’s a camera that uses multiple translucent graphene sensors to create a 3D map of a scene, so that you can pick your focus point after taking a shot. This is a graphene alternative to the ‘light field’ Lytro Illum, but where the graphene camera uses multiple sensor layers, the Illum needs an array of hundreds of thousands of micro lenses to create its images.
To get to the bottom of this idea, we have to look at the properties of graphene a little more closely.
Graphene is very sensitive to light, but a single layer of the stuff only absorbs 2.3 percent of it. One sheet would be useless: it’s almost transparent. A whole bunch arranged through a sensor block, though, would do the trick.
“Graphene detectors can offer very high sensitivity, so you don’t really sacrifice the clarity by making them transparent,” says associate professor of electrical engineering and computer science Zhaohui Zhong.
The University of Michigan’s documentation details a DSLR-size camera with a multi-layer sensor, although it notes that in time this technology could be slimmed down to fit into a phone.
There’s also some suggestion in the design schematic that the layers will be used to separate colours in an image, although at the moment the team primarily talks about how this depth array will make piecing 3D images together much easier.
“Using this principle, it is much easier for the computer to reconstruct the images. The faster processing makes it possible to produce high-speed and high-resolution video,” Zhong writes in the abstract.
Video that can be re-focused post-shoot would be a big upgrade over the Lytro Illum – which only shoots stills – not to mention every other camera out there.
A battery that charges in minutes
Spend 10 minutes searching the internet and you’ll find at least a dozen future battery technologies that sound like they’re about to change our lives – and graphene is behind many of them.
The latest comes from Chinese company Dongxu Optoelectronics, and takes the form of an actual product: the G-King external battery.
It’s a 4800mAh unit, the kind you might buy to keep your phone topped-up on holiday. The special feature is that it charges up in 15 minutes, less than a third of the charge time of today’s top fast-charging phones.
This battery was reportedly shown off at the launch, working, in July 2016.
There’s also the Zap & Go charger, the first graphene supercapacitor charger, which uses tech that could eventually replace lithium-ion batteries in phones and charge your handset incredibly quickly.
“It charges fully in five minutes,” says Quentin Lemarie at the Oxford-based Zapgocharger, which is fresh from a surge of crowdfunding on IndieGoGo.
Benefiting from graphene-enhanced electronics, the working prototypes of this portable charger – which is about the same size as an iPhone 6 – contain a 750mAh battery, which is about half the capacity of an iPhone battery.
“You can charge half of your phone in five minutes,” says Lemarie. “Our eventual aim it to replace the batteries in phones, and to do that we need to make it smaller and thinner. We’re not far off.”
However, going back to Dongxu Optoelectronics, what the brand hasn’t talked about is the factor that matters more in the future of batteries: the density of power stored.
Fast charging is a neat feature, but it’s higher energy density that will change the world. Ultra-high energy density batteries won’t just make our phones last all-week again, they would solve the range issue of electric cars and might one day let airliners run off electricity.
Energy density is why fossil fuels are so useful. We’re on the hunt for an alternative.
This is one of tech’s big challenges: finding the next workable battery technology after lithium ion, the battery type used in today’s phones and electric cars. Some of the more promising recent experiments use a combination of silicon and graphene to improve or replace today’s li-ion designs.
An article on such a battery design was published in Nature in March 2016. It outlines a battery with almost double the energy density of li-ion, even after it’s been charged and depleted a thousand times. It’s not close to the density of fossil fuels, but it’s a huge deal when it could add 100-200 miles to the range of an electric car.
The base of future computer systems
One of the most exciting potential uses for graphene – and also one of the uses that’s in the most danger of turning out to be completely non-viable – is as the replacement for the silicon in our computer chips.
IBM and Intel both dismissed graphene as a future chip material in 2011, but that didn’t stop IBM from ploughing $3 billion into researching post-silicon designs, including graphene, in 2014.
Graphene could still be the wonder material we need, but its main problem is that it’s not a natural semiconductor, so it’ll likely be just a part of the solution, rather than the final answer.
The problem with current silicon processor dies is that they’re not suitable for architectures smaller than seven nanometers. And shrinking of dies is how we traditionally get to faster, more efficient processors.
The first Pentium processors from the early 1990s had 800nm transistors. In 2006, Intel was making chipsets with 65nm transistors. Today’s Skylake processors have 14nm transistors. As we get ‘closer to zero’, miniaturisation becomes harder, and silicon dies appear to be running out of steam.
The failure to find something workable to get us there is perhaps why Intel delayed its shift to 10nm processor architectures in 2015, which we originally expected to see after the current Skylake generation. This has since been pushed back to 2017.
James Baker, of the University of Manchester’s National Graphene Institute, told us that there are “still some significant challenges to replace silicon in computer processors”.
He adds that there is “potential from other 2D materials and heterostructures in the longer term”, with graphene forming just a layer in a future design.
There are some encouraging signs in recent research. Scientists from the Moscow Institute of Physics and Technology recently published a paper on a graphene transistor based on dual layers of graphene in Scientific Reports.
The paper talks about the exact premise of the kind of heterostructure James Baker referred to –graphene on a substrate of boron nitrate – to help solve the issue of future CPU miniaturisation.
What would result is a transistor that runs at a much, much lower voltage than today’s ones. We’ll leave the real-world viability of this proposal to the engineers, but the study’s author suggests it could have a huge effect.
“The transistor requires less energy for switching, chips will require less energy, less heat will be generated, less powerful cooling systems will be needed, and clock speeds can be increased without the worry that the excess heat will destroy the chip,” says Dmitry Svintsov, head of MIPT’s Laboratory of Optoelectronics and Two-Dimensional Materials.
We may be a long way off graphene CPUs, but it’s not time to write off the idea just yet.
The smallest speakers in the world
Regular audio speakers are very physical things. They use drivers that move back and forwards very quickly, exciting the air to create sound waves. Back in 2013, the University of California at Berkeley made an earphone with a graphene driver, but the material has also been used to create a completely different kind of speaker.
A recent article in the ACS Applied Materials & Interface journal outlines a thermoacoustic speaker made using graphene. It’s lab-bound right now, but it could be a fit for mobile devices, as it doesn’t require the kind of speaker cavity normal dynamic driver speakers need.
The way in which it works may sound odd though. A suspension of graphene flakes is freeze-dried to produce an aerogel – an ultra-porous graphene-based structure, a bit like a rigid sponge. This gel is then rapidly heated and cooled to cause air movement similar to that of a normal speaker cone.
The demo speaker array shown off by the researchers at The KAIST College of Engineering in South Korea has a series of 16 of these little thermoacoustic drivers mounted on an ultra-thin film.
A video of it in action shows these speakers aren’t going to be bass monsters – but the larger and lighter the aerogel, the more powerful the sound gets.
“The anlayses showed that a N-rGOA with lower density and larger area can produce a higher sound pressure level,” says CS Kim in the speaker outline article.
This makes sense – that a more porous freeze-dried aerogel spread over a large area will be able to push out greater air-agitating waves of heat.
The important feature of this experiment’s design is that it’s suitable for mass production, making it far less of a fantasy project than some graphene research. Its designers claim the speakers are suitable for mobile devices, and will even work on curved surfaces.
We’re yet to see how much battery drain a thermoacoustic speaker would cause, and how much discernible heat it might produce – but if it makes a tablet sound more like a mini surround sound system, we’re in.
In July 2016, Dassi unveiled the first graphene bike frame. The benefits of the material for bike makers are fairly obvious: as graphene’s strength relative to its weight is so high, graphene should make ultra-rigid, extremely light bike frames a cinch to design.
The hype does need dissecting, though. The Dassi frame is still predominantly a carbon fibre frame, with some layers of graphene reinforcement at its core. Layers of graphene bonded with an epoxy resin sit underneath the carbon fibre, and graphene itself makes up around one percent of the frame.
At this stage it can only be considered a proof of concept, particularly as the frame is around the same weight as a top-end all-carbon one, at 750g. However, Dassi claims the weight will eventually be reduced by several hundred grammes as the application of the graphene is improved, down to “500g unpainted”.
In September 2016 Dassi showed off one of the normal-looking 25 bikes being produced using the initial design, which you can check out on Twitter.
The question that remains is how much of an improvement this graphene addition really brings to the bike’s strength.
Dassi’s claims are big: that it will offer “70% more inter-laminar sheer strength; 50% more fracture toughness; retarded crack propagation; and increased carbon-to-resin adhesion”.
That means you get a frame that won’t crack or snap under extreme pressure, which is the one big issue with carbon fibre bikes – treat them mean and they may one day snap, literally.
It seems likely, though, that the graphene benefits in applications such as this will be far greater when graphene is woven into the carbon fibre, rather than laid out in sheets within a carbon fibre exoskeleton.
Rice University successfully reinforced carbon fibre with graphene flakes in 2013, and a company called Zyvex already makes a carbon fibre graphene composite called Arovex.
Arovex was used in a bike wheel rim back in 2011-2012, in partnership with bike equipment maker Enve. It exists, and pro downhill mountain bikers actually used it.
“Whereas traditional aluminium rims last no more than three downhill runs before needing to be changed, causing an elite race team to change rims more than 180 times during a season, one pair of the new graphene and CNT composite rims have lasted World Cup downhill racing champion Steve Peat the entire 2011 season,” Invest in Graphene claims.
Perhaps this is why we haven’t seen more of these bike rims: you might never need to replace them, offering more speed, more grip, stronger and puncture-resistant tires.
That’s the reason why Vittoria Industries is putting graphene into its top of the range Corsa tires. However, graphene is also going into Vittoria’s carbon wheels.
“We are using are graphene-nanoplatlets in the resin, which we impregnate into the carbon fibre,” says Giulio Cesareo, CEO of Directa Plus, which supplies the graphene.
“The objective was to improve mechanical properties and thermal conductivity, and we were able to get mechanical improvements close to two digits.” The end product is lighter, stronger, and more flexible, with that extra thermal conductivity meaning better stiffness and grip.
However, we will start to see graphene bleed into all sorts of structural uses, particularly if the graphene hype continues.
For example, in July 2016 UK sports car maker BAC showed off a car that uses graphene in its body panels. It was in part a headline-grabbing experiment, but BAC says graphene could eventually be used to reduce car weight by up to 20 percent, for better performance and fuel economy.
Graphene could allow cars to gather, and store, the energy they produce as they move – thereby saving precious fuel. KERS (short for Kinetic Energy Recovery System) was all the rage in the ultra-secretive sport of Formula 1 a few years ago.
Now called ERS, these power units use graphene supercapacitors, and pretty soon so will freight. Saving a staggering 15-25% on fuel consumption, patented nanoporous carbide-derived carbon, better known as ‘curved graphene’, is being used by Skeleton Technologies and Adgero to produce a hybrid system for road freight vehicles where a bank of high-power car batteries – called SkelCaps – work alongside an electrically-driven axle and automatically control the energy recovery.
Soon, the Fitbit, Jawbone, Misfit and other fitness ‘wristables’ are soon going to look clunky – and dumb. Graphene promises not only much thinner (even paper-thin) wrist bands, but they’ll have integrated graphene light sensors and circuitry that bring extra functionality just by using light.
“By shining light on the skin you can find a lot of interesting things about the body,” says Stijn Goossens, Postdoctoral research engineer, Nano-optoelectronics, Institute of Photonic Sciences (ICFO) in Barcelona. “The colours of light absorbed by the skin tells you about heart rate and blood oxygen.”
That’s great for general fitness metrics, but it’s also really useful for, say, premature babies; blood that is low in oxygen is blue-purple, while oxygen-rich blood is bright red.
More useful windows
Graphene’s transparent appearance and super low-power meansnames it can be used in some unexpected places. Since it’s got super-low power consumption and it’s highly sensitive, the tech could be used in inert materials such as windows.
“The light sensors can be embedded in anything, so you could think about putting it in windows or other places where there’s no power, such as packaging,” says Goossens at the ICFO.
“In a window in a building it could detect whether it’s night or day for your curtains to open or close automatically.” It’s also the first step along the way to windows managing to harvest energy during the day and illuminating during the night – while still being transparent.
However, a more short-term killer app is probably as a hands-free system in a car. “You would need four sensors to detect a directionality, so in a car window it could detect motion sensing – you could change the track on a CD just by waving your hand,” says Goossens.
The advantage over existing tech is that graphene can be completely transparent – the entire window could be full of sensors.
Graphene can also be used to make super-thin, super-sensitive image sensors that can detect invisible infra-red light. That means night vision goggles working on graphene-based CMOS sensors that could cost as little as £10 instead of £20,000 once graphene sensors are mass-produced (augmented reality headsets with night vision, anyone?) and spectral applications to differentiate between different organic materials.
“We will also be able to put graphene spectrometers in your phone, so you can see if a mango in a supermarket is ripe, or whether the tyres on your car are worn, or whether a wood product is real wood,” says Goossens at the ICFO. It could also detect harmful chemicals in food.
How close is this? Graphene spectrometers in phones could take as little as two years, but only if there was a lot of targeted investment by one of the big phone/component manufacturers.
Speeding up swimmers
Launched last month at at ISPO Munich by Italian sportswear brand Colmar of ski jackets , ski suits, technical underwear and a polo shirt that all use graphene-infused fabric, called G+. “We exploited the heat generated by the human body itself,” says Laura Rizzi, R&D manager at Directa Plus, who explains that graphene is used as a fabric coating that regulates temperature.
“It helps transfer heat from the hot zone to colder zones one, keeping the wearer comfortable.”
G+ – being used here for the first time – also reduces friction with air and water, so could be useful for increasing agility for general sports, as well as for increasing speed, perhaps for swimmers.
Making water safe
Water, soil and air purification is also possible with graphene. One of these products – Grafysorber from Directa Plus – is super-absorbent, and ideal for oil spills.
“One gram of Grafysorber is able to absorb up to 90 grams of oil,” says Rizzi. The mobile Grafysorber Decontamination Unit contains a plasma machine to produce the wonder material on-site, which is even able to return contaminated water to safe levels for drinking.
“Normally you have to use biological or chemical process to treat contaminated water, but Grafysorber is completely chemical-free,” adds Rizzi.
Love the glove
It’s not often said, but virtual reality isn’t not very convincing. It needs movement sensors to become so, and what better than a pair of super-responsive gloves that are sensitive to tiny changes in motion and temperature?
“Graphene flakes printed in very thin layers are very sensitive to strain,” says Dr Darryl Cotton, Senior Researcher, Nanotechnology, Nokia Research Center, Cambridge. “We’ve also put reduced graphene oxide into a temperature sensor.”
The end result is a glove that, for now, sets off surface-mounted LEDs, but they’re so thin and flexible that they could be used to make virtual reality environments responsive to tiny movements in fingers.
Printed electronics are they next big thing, and graphene is at the forefront. Costing just a few pennies each are paper wristbands or tickets, which have graphene ink printed onto them. In a recent demo, the proximity of a graphene RFID tag to a reader caused a picture to be taken of the wearer or holder.
“This could be used in closed environments such as airports for monitoring passengers boarding a high security flight, or on the London Underground to track which entrances and exits passengers take just by tracking their ticket,” says Dr Thanasis Georgiou, VP, Graphene Security Ltd., Photon Science Institute, University of Manchester.
“Products in supermarkets could have [graphene-based] RFID technology on them so you could know in real-time where products are.”
As well as making shop-lifting much harder, and perhaps even getting rid of the checkout altogether, a connected Internet of Things-like system would be able to see instantly when stocks are running low of specific products.