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CT: If you’ve ever drawn with a pencil, you’ve probably made graphene. The world’s thinnest material is set to revolutionise almost every part of everyday life.
Fascination with this material stems from its remarkable physical properties and the potential applications these properties offer for the future. Although scientists knew one atom thick, two-dimensional crystal graphene existed, no-one had worked out how to extract it from graphite. That was until it was isolated in 2004 by two Russian-born researchers at The University of Manchester, Andre Geim and Kostya Novoselov. This is the story of how that stunning scientific feat came about and why Andre and Kostya won the Nobel Prize in physics for their pioneering work.
S: http://www.graphene.manchester.ac.uk/ (last access: 7 February 2015)
N: 1. Origin: 1980s: blend of graphite and -ene (from Greek -ēnos; Chemistry Forming names of unsaturated hydrocarbons containing a double bond).
2. In simple terms, graphene, is a thin layer of pure carbon; it is a single, tightly packed layer of carbon atoms that are bonded together in a hexagonal honeycomb lattice. In more complex terms, it is an allotrope of carbon in the structure of a plane of sp2 bonded atoms with a molecule bond length of 0.142 nanometres. Layers of graphene stacked on top of each other form graphite, with an interplanar spacing of 0.335 nanometres.
3. It is the thinnest compound known to man at one atom thick, the lightest material known (with 1 square meter coming in at around 0.77 milligrams), the strongest compound discovered (between 100-300 times stronger than steel and with a tensile stiffness of 150,000,000 psi), the best conductor of heat at room temperature and also the best conductor of electricity known (studies have shown electron mobility at values of more than 15,000 cm2·V−1·s−1). Other notable properties of graphene are its unique levels of light absorption at πα ≈ 2.3% of white light, and its potential suitability for use in spin transport.
4. Being able to create supercapacitors out of graphene will possibly be the largest step in electronic engineering in a very long time. While the development of electronic components has been progressing at a very high rate over the last 20 years, power storage solutions such as batteries and capacitors have been the primary limiting factor due to size, power capacity and efficiency (most types of batteries are very inefficient, and capacitors are even less so). For example, with the development of currently available lithium-ion batteries, it is difficult to create a balance between energy density and power density; in this situation, it is essentially about compromising one for the other.
In initial tests carried out, laser-scribed graphene (LSG) supercapacitors (with graphene being the most electronically conductive material known, at 1738 siemens per meter (compared to 100 SI/m for activated carbon)), were shown to offer power density comparable to that of high-power lithium-ion batteries that are in use today. Not only that, but also LSG supercapacitors are highly flexible, light, quick to charge, thin and as previously mentioned, comparably very inexpensive to produce.
Graphene is also being used to boost not only the capacity and charge rate of batteries but also the longevity. Currently, while such materials as silicone are able to store large amounts of energy, that potential amount diminishes drastically on every charge or recharge. With graphene tin oxide being used as an anode in lithium ion batteries for example, batteries can be made to last much longer between charges (potential capacity has increased by a factor of 10), and with almost no reduction in storage capacity between charges, effectively making technology such as electronically powered vehicles a much more viable transport solution in the future. This means that batteries (or capacitors) can be developed to last much longer and at higher capacities than previously realised. Also, it means that electronic devices may be able to be charged within seconds, rather than minute or hours and have hugely improved longevity.
S: 1. OD – http://www.oxforddictionaries.com/definition/english/graphene (last access: 7 February 2015). 2, 3 & 4. http://www.graphenea.com/pages/graphene#.VNZmIHaIkos (last access: 7 February 2015).
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