Advanced electrical conductors can revolutionize our lives, enabling billions of dollars in energy savings and facilitating a transition to an electric society. Nanocarbons present a unique opportunity for developing advanced conductors for electrical power, communications, electronics, and electric machines. In this webinar, the major research progress in this field will be presented. The presenter will also elucidate the competitiveness and implications of advanced conductors with respect to conventional ones and describe their materials science, properties, and characterization. Finally, he will propose several areas of future research for advanced electrical conductors.
- Dr Mehran Tehrani, University of Texas at Austin
Links & resources
Questions received during the webinar dd April 21, 2021
- Have you heard of composite conductors combined aluminium with carbon nanotubes or graphene?
> Both CNTs and graphene have been added to aluminum. Improvements are usually seen in mechanical properties accompanied with a degradation of electrical conductivity of aluminum.
- Can you provide some information about the ampacity of the hybrid conductor made of copper and nanofiber?
> For a same diameter wire, current rating of a copper wire (current to reach a certain temperature, usually 60-90C) is higher than any copper-composite wire; I am not aware of any composite copper wire with a higher electrical conductivity than copper. For bare copper wires, a black carbon coating might improve ampacity by improving irradiation heat losses.
- When will these alternatives be ready and economically viable?
> Some are already available for EMI shielding and data cables. Ultra-conductors will be hopefully in the next few years.
- Today is it possible realize a stator or rotor winding with CNT-copper or graphene-copper for having a greater conductivity?
- Can we have information about the producers of these conductors?
> Please see https://onlinelibrary.wiley.com/doi/pdf/10.1002/pssa.202000704 and references thereof.
- I have a question about the mechanical properties of advanced electrical conductors. Since these conductors are often fabricated in small size, what is the best mechanical experiment for obtaining their mechanical properties such as strength?
> For films, nanoindentation or microhardness tests would be appropriate. Size of the indenter should be several times larger than feature sizes that strengthen the composite. Small sized dog-bones can be tested using low-load tensile machines.
- Have you compare superconductors with Graphene/CNT-copper? Or is there any comparison for that?
> They have different applications and therefore a comparison is not meaningful. Advanced electrical conductors should be only compared with metallic conductors.
- As a fire safety engineer what research has been conducted on these new combinational materials for the building environment?
> Nothing that I am aware of.
- When do you estimate enhanced, and commercially viable, Cu/CNT conductors will be available for use in electrical machines such as motors and transformers?
> Meters scale CNT-Cu wires with electrical conductivities better than copper have not been demonstrated yet. Although there are lab scale demonstrations of ultra-conductivity in Cu-CNT and Cu-graphene, none of these studies have been reproduced, as far as I know.
- In order to use these conductors to build electric motors, what are the magnetic characteristics?
> I don’t know.
- I'm in the land High voltage industry. We produce conductors with Copper. Is there today already existing copper Alloy grade with Nanocarbon tube which can already be used ? is there already Conductor maunfactured with theses grades and if yes what are the results?
> I am not aware of any commercial product but research on this topic is ongoing.
- What do you know about what is happening in China? Any performance numbers there?
> No one knows. I have seen some high-quality work out of china.
- What is the max length/ diameter of a CNT copper wire and what is the production method today? All conventional production method are not capable to be applied. How to apply to mass production?
> There are several ways to manufacture such wires with Cu electrodeposition being the most widely used.