Improved battery technology may be an important step towards increased electrification of road transport, and may one day, through a network of on-grid EVs, help create the dreamed global storage facility for green electricity – alleviating the problems the straggling output of for instance wind and solar energy poses today.
So it was good news, two months ago, when MIT researchers said they could boost battery performance tenfold. The magic trick is implementing that newly discovered superconductor: graphene. Graphene’s virtues are not restricted to battery technology. In fact, take any piece of existing electronic technology, add a touch of the gold dust that is microscopic graphene, and you’re likely to make it better, smaller, more energy-efficient – and most of all: scientifically hip.
This week, Science published new research on a graphene implementation that even bypasses the battery: the ultracapacitor. This power source for small electronics can recharge in seconds. If built with graphene, in under 200 microseconds [will impatient consumers finally stop complaining?].
Like the improvements with batteries and ultracapacitors, this year alone, in universities and other scientific institutions thousands of different studies focus on graphene. The peer-reviewed results are gradually seeping into the scientific literature, although many more publications are to be awaited. The word graphene will most likely be hot for years to come.
Just six years ago no one would have heard of it. Moreover, anyone carrying some common chemical sense would have thought it impossible, if not theoretically, then at least practically, considered unproducible.
Yet graphene is. It wasn’t until 2004, but it is now. Andre Geim and Kostya Novoselov made it; two researchers at the University of Manchester – Geim is also professor at Nijmegen Radboud University, the Netherlands.
Graphene is very, very thin to start with. And it happens to be extremely strong, perfectly conductive, chemically stable and impermeable yet completely transparent. Oh, and it is made out of nothing more than good old over-abundant carbon. With Mars proving a little distant, obesity too firmly gripped by human choice and climate change still somewhat unsolvable, science has settled for consumer electronics. It is a bit like investing in gold. Gadgets will always sell. Especially the new ones, the smaller ones. Well, scepticism aside, who knows. Gadgets may even turn useful one day.
Graphene most likely will: solar panels are. Hospital equipment is. Bits Of Science needs its server. You seem to make good use of your computer. All in all the scientific community has jumped the material in the last few years.
So, what’s so special about graphene?
The number of chemical bonds within a molecule or the interconnectedness of the different atoms it contains is an important indication of the strength of the material. The structure is optimal when it reaches symmetry in all dimensions – and can theoretically continue eternally.
That is the case with for instance diamond. Diamond consists of a tetrahedral arrangement of carbon atoms, which all have a connection to their neighbour atoms at fixed distances. Each carbon atoms is bound to four other carbon atoms, continuing in all directions, until the molecule is disturbed, hopefully at a very late stage, from the financial perspective of its human owner.
However strong the symmetry makes it, diamond cannot stretch. It is extremely hard, but a ‘slice of diamond’ can break. Enter graphene. It is another substance that consists of carbon atoms only. This time these are arranged in a honeycomb structure that is only one atom thick. Each atom is chemically bound to three other carbon atoms, in a two dimensional plane. It could have been four atoms of course (as in diamond or in the number of bonds a carbon atom in methane (CH4) has) but that would have cost the molecule symmetrical balance.
Thanks to the honeycomb symmetry the plane is extremely stress-resistant – 200 times more than steel to name one comparison.
Obviously the weirdest characteristic is its extreme lack of thickness. Try and hold a sheet of anything one atom thick.
It is very unlikely the substance exists in nature. But pile various sheets of graphene on top of each other and you get common graphite. It sounded unlikely, but it just worked: scotch tape. Or something like that.
Listen to Andre Geim’s story on the BBC World Service Discovery Podcast and hear his views on a future world with his chemical prodigy implemented – in all our households.
(c) Rolf Schuttenhelm | www.bitsofscience.org