The latest wonder material graphene promises to provide all we need in clean energies and superefficient technologies and mop up greenhouse gases and toxic waste; too good to be true? Dr. Mae-Wan Ho
Stop fretting over climate change and greenhouse gases; no more drilling for oil, tar sands, shale gas; sweep away coal and nuclear power, along with outmoded solar panels, electronics, photonics, batteries, and anything that requires toxic rare earths, because graphene is replacing and will replace them all, and there’s plenty of graphite to make it from. Better yet, greenhouse gases such as methane and carbon dioxide could provide the carbon to make it in bulk (see [1] Graphene from Greenhouse Gases to Save the Climate, SiS 59), thus transforming climate-changing wastes into a resource whose applications are limited only by imagination and invention; sounds too good to be true?
The new superstar in materials science and condensed matter physics is a flat single layer of carbon atoms packed into a crystalline honeycomb lattice that could go on forever. Curled up, it gives fullerenes (the familiar buckyballs), rolled up, it forms carbon nanotubes, and stacked up in layers, it is the graphite in our pencils. Graphite is abundant and has a good safety record (though graphene the single layer should not be assumed safe, as it has very different properties from bulk graphite, and need to be studied carefully for toxicity). Graphene has garnered practically all the superlatives since propelled into the limelight by Russian-born physicists Andre Geim and Konstantin Novoselov at Manchester University in the UK in 2004 [2]. They isolated graphene from graphite using sticky tape, and was awarded the 2010 Nobel Prize in physics for their “groundbreaking” experiments on the material (see [3] Why Graphene is Amazing, SiS 59).
Physicists are ecstatic over the macroscopic quantum effects and other astonishing phenomena that can be demonstrated at room temperatures on their bench tops [3, 4], while those with an eye for applications are having a field day designing and testing prototype contraptions.
Electronically, graphene is a superconductor even at room temperatures. It conducts much easier and faster than copper and at a million times the current density. That means ~1013 cm-2 zero-mass charge carriers travelling ‘ballistically’ without scattering (resistance) for tens of microns at ~1/100 the speed of light. These properties are very useful indeed for making faster supercomputers.
Graphene is unique in having zero band-gap, i.e., there is no energy gap between the electron bound to an atom and the conduction band when it starts to move; consequently, it can potentially make use of photons with any energy to generate electricity, even thermal energies. This property is very useful for electrodes and solar cells (see [5] Graphene and Solar Power for the Masses, SiS 59). The zero band-gap means it cannot be turned off, which is a limitation for transistors, though not for other optoelectronic devices. Band gaps can be created by introducing an electric field, or doping with a small amount of impurities.
Graphene conducts heat at > 5 000 W/ metre Kelvin, much better than all other carbon structures such as carbon nanotubes, graphite and diamond (hitherto the champion at about 1 000 W/mK). This makes graphene ideal for heat transport in superfast processors for computers, which is reaching a bottleneck due to all the heat generated that cannot be carried away fast enough (see [6] The Computer Aspires to the Human Brain, SiS 58).
Graphene is the thinnest, toughest material known, harder than diamond, and 300 times tougher than steel: it takes the weight of an elephant balanced on a needle-point to break this one-atom thick layer; its tensile strength exceeding 1 TPa [4]. Yet, it is flexible, and very elastic for a crystal, stretching up to 20 % of its length [7]. The combination of lightweight and toughness is great for building airplanes and wind turbine blades, for example.
Graphene absorbs just 2.3 % of incident light, which makes it more transparent than anything else; hence a boon for unbreakable touchscreens and solar cell electrodes.
Graphene is the most impermeable atomic layer; it will not let any liquid or gas pass through, a property that can be exploited as a barrier film or filtration membrane (see [8] Graphene Molecular Sieves for Desalination and Purifcation, SiS 59).
Graphene can be chemically modified in numerous ways with further undreamt of properties yet to be discovered. Graphene oxide is excellent for removing radioactive nuclides from nuclear waste water and contaminated water [9] (see [10] Graphene Oxide for Nuclear Decontamination, SiS 59), which is just what the victims of the Fukushima nuclear disaster need to protect themselves from further exposure to the radioactive fallout (see [11] Death Camp Fukushima Chernobyl - an ISIS special report)
And it is definitely not just hype nor exaggerated hope, though the entire world seems to be in the grips of a graphene fever. Despite that, public funding has been relatively ungenerous compared to other areas (see [6]). The UK government has allocated €70 m to graphene research [12], but most of it will end up paying for a new graphene institute next to the University of Manchester building where Geim and Novoselov isolated graphene. The EU has awarded €1 bn for graphene research over the next 10 years to a consortium that includes many companies [13]. The US government has yet to announce any funding initiative for graphene.
At the end of 2012, the Intellectual Property Office in Cambridge UK recorded 2 204 (30 %) graphene patent publications from China, 1 754 from the US, 1 160 from South Korea, and 54 from the UK [14]. Samsung has more patents than any other company in the world. And the total number is growing exponentially.
Not surprisingly, China is first to begin industrial production of graphene for its numerous applications.
On 5 December 2012, graphene coated aluminium foil was put into production by Ningbo Morsh Technology Company Ltd in Zhejian Province [15]. It expects to increase its annual output of 30 tons to 300 tons by August 2013; and another graphene production line with an annual capacity of 1 000 tons is planned along with a doubling of its graphene coated aluminum foil project, according to Dr. Liu Zhaoping at Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences. Liu’s team also fabricated graphene-based nanocomposites for Li battery application, having made many research breakthroughs in recent years. His team was the first to succeed in developing a very low cost and scalable method for making high quality graphene.
The graphene coated aluminium foil will be used to increase conductivity in cathodes for lithium batteries. The ultrathin graphene coating (< 1 nm) has the potential to reduce interface resistance and increase the adhesive strength between active materials and the metal foil, thereby enhancing the rate capacity and cycling stability of the batteries.
But Liu is not alone in China. In December 2012, The Institute of Metal Research, Chinese Academy of Sciences announced that their pilot production line for low cost and large-scale graphene preparation technology had been successful, and is expected to conclude a joint venture for industrialization with the Jinlu Group in Deyang City, Sichuan province. Some local governments have started to plan graphene industrial parks to promote a related industry chain, including the provinces of Ninde, Fujian, Shenszhen, Guangdong and beyond
Graphene has certainly initiated a new age of carbon for electronics and related industry. It could be much bigger than the silicon revolution. Perhaps the most immediate is a quantum leap in miniaturization that has reached an impasse due to the lack of success in miniaturizing energy storage ([16] Graphene Micro-Supercapacitors for On-Chip Energy Store, SiS 59).
Article first published 03/07/13
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Susan Rigali Comment left 4th July 2013 01:01:03
Amazing as this is the very substance that I used to increase temperature in my solar cooking. By making a polymer that is food grade containing graphene that has GRAS approval, I have been able to increase efficiency by 20-50%. The fact that this element also is an amazing conductor leaves all last century thinking as a history we are ready to move on from. Thanks for this I-SIS you are amazing too.
Mae-Wan Comment left 4th July 2013 03:03:27
Hi Susan,
You are way ahead of everyone. Tell us more about this graphene polymer that has GRAS approval, and how it is used.
Thanks
maewan
Cindy Symington Comment left 6th July 2013 03:03:08
THANK YOU!! The kinds of papers I read here are not only enlightening but offer hope for the future in ways that nothing else can.
Graphene is something to watch; thank you!
Dr. James R. Pannozzi DOM Comment left 15th July 2013 09:09:20
Thank you for quite an interesting paper and this is quite an interesting site.
I find it interesting enough, that I shall be looking at some of the books an articles by Dr. Mae-Wan Ho. Keep up the great work. More comments later.
Susan Rigali Comment left 25th July 2013 06:06:30
I read your article and got excited about the use of graphite as a new source of energy. I knew that graphite holds an electric charge but was also interested in a carbon that could be recognized by GRAS in constructing thermal capabilities in solar cookery. The fact that it is of course black is another reason temperatures can be increased by 20-50 degrees. I used a vegetable oil with powdered graphite and baked stainless steel cooking pans in my larger solar oven making a washable coating that increases temps and holds heat. Sorry about the goof on saying the use was graphene as I meant graphite. Also, I applied in layers and treated to high solar temps to achieve what seems to be a durable coat. Still testing on different levels as I believe that these methods could prove useful in many parts of the world.
Best to you, thanks for your work.
Susan