I have been hearing about carbon nanotubes for a while now, and they are indeed very promising, as this news proves:
Rice University researchers have developed a carbon-nanotube-based cable that is able to carry as much electric current as copper, and it is lighter. This has potential sustainability, durability and efficiency advantages.
Hollow pure carbon nanotube wires are an order of magnitude more electrically conductive than copper, and copper is actually the best electrical conductor in widespread use today.
Sustainability: The sustainability advantage is that it can be made of pure carbon, which is an abundant element that does not have the demand and supply issues that copper does. Copper has gotten expensive and has thus driven up the cost of generators, electric motors, most electronics, and everything else that requires significant amounts of copper wire.
Another sustainability advantage is that it helps to facilitate the use of sustainable energy sources such as wind farms and solar power plants, which are often very far from civilization in deserts and out on plains. The long distance of some wind farms from civilization is a problem because long cables are required to transmit the electricity to civilization, and longer cables have a higher electrical resistance, and waste more electricity.
As copper is a non-renewable metal that is mined from the earth (like iron and other metals), this problem will get worse, but recycling has been helping to offset demand for mined copper and recycling is expected to increase in the future as mined copper becomes more expensive. It will become absolutely necessary.
Durability: Carbon-nanotube-based materials can be and often are significantly stronger and lighter than copper, steel and aluminium. This is good for automobiles, aircrafts, and basically everything that moves or is portable. Carbon nanotubes do not rust or corrode. They are not brittle like some metals are (they are actually flexible and malleable), and they are also thermally conductive.
Improved thermal conductivity is actually beneficial to electrical conductivity because it radiates more of the heat than it generates, so it operates cooler and resistance to the flow of electric current increases with the temperature of the wire.
How these carbon nanotube cables are made:
- They start by removing impurities from a lump of double-walled carbon nanotubes.
- They add sulfuric acid so that the lump can be spread out into a thin film.
- Tweezers are used to grip the edges of the film and twist it into a fiber.
- Finally, the sulfuric acid is rinsed off and the cable is exposed to iodine vapour at a high temperature, which penetrates into the nanotubes inside the cable, increasing conductivity.
The Rice University researchers said that extending the length of the cable has no measurable effect on conductivity, which is good news for electricity transmission.
More on carbon nanotubes and related stories:
- Samsung Demonstrates World’s First Carbon-Nanotube Based Display
- London Calling: Nexans to Supply Undersea Cable for World’s Largest Wind Farm
- Quick-Charge Batteries Get a Boost from Defective Carbon Nanotubes
Photo Credit: Eric Wieser