Ultra-Long Carbon Nanotubes Could Serve as Future Transmission Lines

Nov 10, 2009 by Lisa Zyga weblog
carbon fiber
Carbon nanotube fibers hundreds of meters long could be fabricated by being processed in a superacid. Image credit: Rice University.

(PhysOrg.com) -- When it comes to carbon nanotubes, the majority of research so far has focused on small-scale applications. But now, a team of researchers from Rice University has created carbon nanotubes that are hundreds of meters long, yet just 50 micrometers thick. The researchers say there is no limit to how long the nanotubes can be made, which opens the doors to large-scale applications including using nanotubes as electrical transmission lines and as the basis of structural materials.

The Rice project began in 2001, led by the late Nobel laureate Richard Smalley. After years of research investigating solution-processing techniques, the scientists found that a superacid called chlorosulphonic acid could spontaneously dissolve carbon nanotubes at concentrations 1,000 times greater than any other solvent. The method can produce well-aligned carbon nanotubes on a large scale, in which nanotubes can be shot out of a nozzle similar to a shower head. The researchers have published the details of the acid-processing technique in a recent issue of Nature .

Since carbon nanotubes are highly conductive, the researchers are currently working on a project for making electrical transmission lines. "Metallic nanotubes conduct better than copper, they're lighter, and they fail less often," said Rice chemical engineering professor Matteo Pasquali.

To make transmission lines, the researchers will need extremely large amounts of metallic nanotubes. Currently, there aren't any good methods that can make large batches of nanotubes that contain all metallic nanotubes without any semiconducting nanotubes. But some recent research in this area has been promising, and the researchers predict that a breakthrough could occur in the near future.

More information: True solutions of single-walled carbon nanotubes for assembly into macroscopic materials, Nature Nanotechnology, Published online: 1 November 2009; doi:10.1038/nnano.2009.302

via: Technology Review

© 2009 PhysOrg.com

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El_Nose
3.7 / 5 (3) Nov 10, 2009
does anyone know if it is metallic or semiconducting nanotubes that are needed for a possible space elevator??

I say ditch the transmission lines idea and push for superconducting transmission lines. yeah it costs a bit to cool but if we are really moving toward a green and effecient power generating grid then when its 4oclock in Cali - solar power could help out Mississipi where it is 7pm
Sonhouse
5 / 5 (3) Nov 10, 2009
does anyone know if it is metallic or semiconducting nanotubes that are needed for a possible space elevator??

I say ditch the transmission lines idea and push for superconducting transmission lines. yeah it costs a bit to cool but if we are really moving toward a green and effecient power generating grid then when its 4oclock in Cali - solar power could help out Mississipi where it is 7pm


When they say it conducts better than copper, some reports I see show it conducting 1000X better so superconductors may not be better and for sure will be more machine intensive with long runs of LN2 lines which have to be insulated.
It would be really good for the space elevator if the nanotubes were conductive, for one thing it would be a very long cable in a magnetic field and as such could generate electricity directly. The thing is making 160,000 Km lengths that are about 100X stronger than steel. It is an exciting time for sure in the nanotube world.
fuzz54
4.5 / 5 (2) Nov 10, 2009
You need very very pure nanotubes for the 1000X copper number, but this technique will be around waiting for the day that we are able to create almost pure conducting nanotubes at low cost. Shouldn't be long.
grgfraiser
4.7 / 5 (3) Nov 10, 2009
they should also be able to use MCNT in electric motors and generators, just think if you can make an electric motor at least 100 times more efficient and powerful you wouldn't need a lot of batteries.
zzthree
4.5 / 5 (2) Nov 10, 2009
they should also be able to use MCNT in electric motors and generators, just think if you can make an electric motor at least 100 times more efficient and powerful you wouldn't need a lot of batteries.

How are you going to improve efficiency of something which get already around 90% 100 times ? Electric motor which makes 90 kW mechanic work with 1 kW of electric power ? Impossible . Tesla 2010 Roadster's electric motor has average efficiency of 92% and Large Utility Generators can have up to 98% efficiency
kcameron
3 / 5 (1) Nov 10, 2009
The research is promising but, as the linked article states, they must still find a way to create large quantities of metallic-only single-walled nanotubes. There's been progress on that front too but we're probably still decades away from seeing such wires deployed in large quantities.

I'm not sure why the article focuses on transmission lines. In my mind, it's far more important that such conductors would revolutionize electric motors and make magnetic energy storage practical.

Sonhouse:
1000X copper's conductivity? Do you have a reference for that? I thought cnt would give something like 3-5X; which would still be revolutionary.
zzthree
4.3 / 5 (3) Nov 10, 2009
This is VERY POOR AND MISLEADING article they have made FIBERS from nanotubes hundreds of meters long and 50 micrometers thick NOT NANOTUBES 100m long 50 micrometer thick. Even the name of the original article should say it to you : True solutions of single-walled carbon nanotubes for ASSEMBLY INTO MACROSCOPIC MATERIALS.
kcameron
5 / 5 (2) Nov 10, 2009

How are you going to improve efficiency of something which get already around 90% 100 times ? Electric motor which makes 90 kW mechanic work with 1 kW of electric power ? Impossible . Tesla 2010 Roadster's electric motor has average efficiency of 92% and Large Utility Generators can have up to 98% efficiency


Yes increasing efficiency by 100X is impossible.

But, even at 90% efficiency, motor/generator losses are important. Efficiency is everything in electric cars. If the efficiency could be improved to say 99%, then the car will go 10% farther on a charge. On top of that one would get 10% more energy recovery from regenerative braking. Even more importantly, the motor size and weight could be reduced drastically which would also increase efficiency. Such motors might even be small enough to incorporate into the wheels without adding too much unsprung weight. All in all, it's conceivable that an electric car's range might be doubled compared to using copper.
nkalanaga
4 / 5 (1) Nov 10, 2009
Structurally it doesn't matter what kind off nanotubes you use for a space elevator. Conductive ones would make it a generating station, but what would the results be of drawing power from the ionosphere and magnetic fields?

On the one hand, there may not be that much usable power there, if the ionosphere doesn't recharge fast enough, or if the cable isn't moving with respect to the magnetic field

On the other hand, if there's lots of power available, could we control it, or would we have the world's largest lighting bolt?
Graeme
4.5 / 5 (2) Nov 10, 2009
This assembly probably does not yield a fibre that conducts 1000x better than copper. However even a poorly conducting rod will get a huge corona discharge There will be of the order of million of volts difference between it and the upper atmosphere if you try to make a space elevator. You could expect significant damage from this.
Sonhouse
4.5 / 5 (4) Nov 10, 2009
they should also be able to use MCNT in electric motors and generators, just think if you can make an electric motor at least 100 times more efficient and powerful you wouldn't need a lot of batteries.

A thousand HP motor takes a thousand hp of energy even if it is 100% efficient. Making motors out of nanotubes that conduct 1000X more than copper mean LIGHTER not less energy since existing motors are already way past 90% efficient already. With nanotubes or room temp superconductors which it looks like pure nanotubes approach already, motors would be a lot smaller in diameter and be a lot lighter for one thing because carbon is pound for pound :) lighter than copper. So you use less windings and so the motor may end up being say, only twice the diameter of the shaft or better and a lot lighter. Don't read less energy, it won't save much, a few percent only but they would for sure be a lot smaller for the same power.
Sonhouse
not rated yet Nov 10, 2009
The research is promising but, as the linked article states, they must still find a way to create large quantities of metallic-only single-walled nanotubes. There's been progress on that front too but we're probably still decades away from seeing such wires deployed in large quantities.

I'm not sure why the article focuses on transmission lines. In my mind, it's far more important that such conductors would revolutionize electric motors and make magnetic energy storage practical.

Sonhouse:
1000X copper's conductivity? Do you have a reference for that? I thought cnt would give something like 3-5X; which would still be revolutionary.


Here is one link: A wiki piece, scroll down to 'electrical properties' http://en.wikiped...nanotube
Yulia_Rudy
not rated yet Nov 11, 2009
It seems to me or this material doubles this one: http://www.physor...59.html. No?
KBK
not rated yet Nov 15, 2009
SPACE ELEVATOR here we come! Arthur would be proud.

"Structurally it doesn't matter what kind off nanotubes you use for a space elevator. Conductive ones would make it a generating station, but what would the results be of drawing power from the ionosphere and magnetic fields?"

It is expected that conductivity to some degree should be there to dissipate building of charge but not so conductive that it becomes a lightning rod.
Canman
not rated yet Nov 19, 2009
zzthree has a point. The article says that this method can create "well alligned" nanotubes. Well, what is the median length of each nanotube within the fiber? Millimeters? Centimeters? At what length do you get good tensile strength?
Also, can we expect this method to produce sheets?
What year can I pull up a you-tube video of a thread holding up a three hundred pound man?

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