Just last week I covered research that seemed to have put the final kibosh on the possibility of replacing copper in logic or memory devices with carbon nanotubes (CNTs).
While the NIST researchers responsible for that report still maintained that carbon nanotubes could be useful in for “interconnects for flexible electronic displays or photovoltaics,” it didn’t sound particularly encouraging for using CNTs in place of copper.But this week I came across research that demonstrated that CNTs look to be a promising replacement for copper in wires for conducting electricity, such as in power transmission cables.
Researchers at Rice University published their work in the Nature journal Scientific Reports. While they concede that making “electrically conducting cables from macroscopic aggregates of carbon nanotubes, to replace metallic wires, is still a dream”, it seems “the conductivity variation as a function of temperature for the cables is five times smaller than that for copper.”
The reason for replacing metal wires with CNT-based wires centers primarily around weight factors that may be important in weight-sensitive applications, such as airplanes and automobiles. Also, “the conductivity-to-weight ratio (called specific conductivity) beats metals, including copper and silver, and is second only to the metal with highest specific conductivity, sodium.”Impressive, but what about reliability issues that were brought to the fore in recent NIST research? Apparently, the CNT-based wires did not show any signs of degradation during the demonstration in which the wire powered a light bulb for days on end.
Interesting research, especially since it showed the reliability of CNT wires braided into the macroscale, but it’s not entirely clear at this point where this research is headed as far as applications are concerned. A “dream” is still where we are with this one.
Dexter Johnson is a contributing editor at IEEE Spectrum, with a focus on nanotechnology.