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You might have seen in the short 2 minute video here: billionsinchange.com/solutions/limitless-energy that the Billionaire Founder (net worth $4 billion) Manoj Bhargava talks about creating cables from graphene to conduct heat from the underground sections of the earth to the surface.

But as per the properties of graphene, it is only a good conductor if the number of layers is one or very few. Once you start stacking it up, it is just normal graphite and it's conductivity gets reduced.

What's proposed in the video is a cable made from graphene. My question is how is it possible to make a graphene rope without stacking up graphene layers (and thus ending up with graphite) or without converting it into nanotubes?

I would also like to know why stacking up graphene reduces it's conductivity? Why don't the layers behave independent of each other?

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    $\begingroup$ The first paragraph is about a scam, so why don't you get rid of it. As to why stacking graphene changes the conductivity, it is because the stacking results in interactions between the layer, which changes the electronic bonding. Now, why single layers of graphene have the electronic structure that they do is an interesting problem in solid state physics. $\endgroup$ – Jon Custer Mar 2 '16 at 16:26
  • $\begingroup$ @JonCuster I do not know how it is a scam. They have already started distributing some of the stuff here in India. Have a look at their other projects. You could be right but at the moment it cannot be a scam. Do you believe one cannot make cables from graphene? $\endgroup$ – rahulgarg12342 Mar 3 '16 at 5:55
  • $\begingroup$ I'm sorry, but any sales pitch invoking 'limitless energy' with credibility based on net worth screams SCAM! $\endgroup$ – Jon Custer Mar 3 '16 at 15:39
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    $\begingroup$ @JonCuster hahaha I completely agree with you. But it's not perpetual energy. Obviously limitless energy is the sales pitch but they're actually using geothermal energy. Which to some extent is enormous compared to the energy requirements of humans on earth. $\endgroup$ – rahulgarg12342 Mar 3 '16 at 16:45
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According to Jesus de La Fuente, CEO of Graphenea:

Graphene is, basically, a single atomic layer of graphite; an abundant mineral which is an allotrope of carbon that is made up of very tightly bonded carbon atoms organised into a hexagonal lattice.

He also states that there are three commonly-known naturally occuring allotropes of carbon - Diamond, Graphite, and amorphous carbon. Graphene's structure is similar to that of Graphite, but Graphene itself is much different because it has a $sp^2$ hybridization, compared to $sp^3$ hybridization of carbon in the form of Diamond, and Graphene has a thickness of just 0.345Nm (nanometers). This means that it does not form tetrahedrals like common carbon atoms, making Graphene similar but special compared to other forms of carbon.

Also stating Jesus de La Fuente in Graphite-Graphene Comparison:

Graphene is fundamentally one single layer of graphite; a layer of $sp^2$ bonded carbon atoms arranged in a honeycomb (hexagonal) lattice. However, graphene offers some impressive properties that exceed those of graphite as it is isolated from its ‘mother material’.

To elaborate, Graphene has special properties that set it apart. There are similarities: stacking layers of Graphene may be similar to creating Graphite; creating a rope of Graphene may be similar to creating Crabon Nano-tubes; both have $sp^2$ hybridizations. However, Graphene has special properties that make it stronger when stacked because of how it is extracted and isolated.

As for the conductivity, Jesus de La Fuente states that it's electronic properties is what sets it apart (See Graphite-Graphene Comparison). Fundamentally, Graphene is a zero-overlap semi-metal, with both holes and electrons as charge carriers, that has very high electrical conductivity by itself. Graphite carbon allotropes have 4 electrons in it's valence shell available for bonding, however, Graphene has 3 electrons that are bonded with other Graphene atoms in the 2D Plane (a.k.a. other Graphene atoms next to it on the same one-atom thick sheet). This makes a single sheet very conductive, because the remaining electron that isn't bonded with other Graphenes in the same sheet are in the 3D Plane (above and below the sheet), causing what is called, pi electrons. However, when Graphene sheets are stacked together, their pi electrons bond with each other, thus reducing the electric conductivity of the Graphene.

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    $\begingroup$ Welcome to Chemistry.SE! Take the tour to get familiar with this site. Mathematical expressions and equations can be formatted using $\LaTeX$ syntax. For more information in general have a look at the help center. 1. There are more than the mentioned three naturally occurring allotropes 2. Hybridisation in graphite is in first approximation sp² not sp³ 3. A thickness of Newton metre? 4. Stacking graphene layers is creating graphite 5. this does not address the part of the graphene rope $\endgroup$ – Martin - マーチン Mar 9 '16 at 4:52
  • $\begingroup$ 1. Rephrased 2. Changed and fixed 3. Changed to Nanometer 4. Rephrased to be more clear 5. Added to content $\endgroup$ – Abob Mar 9 '16 at 19:28

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