2010-03-13

New Way to Produce Electricity: Thermopower Waves in Carbon Nanotubes

Clipped from: BBC News - Nanometre 'fuses' for high-performance batteries
BBC

Nanometre 'fuses' for high-performance batteries

Minuscule tubes coated with a chemical fuel can act as a power source with 100 times more electrical power by weight than conventional batteries.

As these nano-scale "fuses" burn, they drive an electrical current along their length at staggering speeds.


The never-before-seen phenomenon could lead to a raft of energy applications.

Researchers reporting in Nature Materials say that unlike normal batteries, the nanotubes never lose their stored energy if left to sit. 

Clipped from: Big power from tiny wires



Big power from tiny wires

New discovery shows carbon nanotubes can produce powerful waves that could be harnessed for new energy systems.

A carbon nanotube (shown in illustration) can produce a very rapid wave of power when it is coated by a layer of fuel and ignited, so that heat travels along the tube.


A previously unknown phenomenon

In the new experiments, each of these electrically and thermally conductive nanotubes was coated with a layer of a reactive fuel that can produce heat by decomposing. This fuel was then ignited at one end of the nanotube using either a laser beam or a high-voltage spark, and the result was a fast-moving thermal wave traveling along the length of the carbon nanotube like a flame speeding along the length of a lit fuse. Heat from the fuel goes into the nanotube, where it travels thousands of times faster than in the fuel itself.  As the heat feeds back to the fuel coating, a thermal wave is created that is guided along the nanotube. With a temperature of 3,000 kelvins, this ring of heat speeds along the tube 10,000 times faster than the normal spread of this chemical reaction. The heating produced by that combustion, it turns out, also pushes electrons along the tube, creating a  substantial electrical current.


Clipped from: YouTube - Nanotube fuses for energy



The never-before-seen phenomenon could lead to a raft of energy applications.
Researchers reporting in Nature Materials say that unlike normal batteries, the nanotubes never lose their stored energy if left to sit.


The team, led by Michael Strano of the Massachusetts Institute of Technology, coated their nanotubes - cylinders just billionths of a metre across - with a chemical fuel known as cyclotrimethylene trinitramine. 



Clipped from: Chemically driven carbon-nanotube-guided thermopower waves : Abstract : Nature Materials
Nature Materials
Published online: 7 March 2010 | doi:10.1038/nmat2714

Chemically driven carbon-nanotube-guided thermopower waves

Wonjoon Choi, Seunghyun Hong, Joel T. Abrahamson, Jae-Hee Han, Changsik Song, Nitish Nair, Seunghyun Baik & Michael S. Strano



Sources:
  1. BBC News - Nanometre 'fuses' for high-performance batteries
  2. Big power from tiny wires
  3. YouTube - Nanotube fuses for energy
  4. Chemically driven carbon-nanotube-guided thermopower waves : Abstract : Nature Materials
  5. MIT Discovers Thermopower Waves which Have Hundreds of Times the Energy by Weight of Lithium ion Batteries
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