KIST’s copper-free electric motor prototype uses carbon nanotubes

Copper is one of the key materials used in electric motors - but what if an electric motor without copper were actually possible? It would be a game-changer, and that possibility has just moved a major step closer.

KIST copper-free electric motor prototype using carbon nanotubes

Researchers at KIST (Korea Institute of Science and Technology) have built a prototype electric motor without copper, replacing traditional metal windings with a network of cabling made from carbon nanotubes.

This approach could make crucial components such as electric motors far lighter, while also offering the potential to sharply cut the emissions linked to manufacturing motors for electric vehicles.

Proof-of-concept tests on a scale car

To demonstrate that the idea works in practice, KIST carried out tests using a small scale-model car fitted with a prototype of this copper-free electric motor.

The motor managed 3420 rpm at 3 Volts, which may seem low next to the 18 120 rpm achieved by a comparable electric motor using copper.

In the same trials, the model vehicle travelled 10 metres in 25s, powered by a 3 V battery. The figures might sound modest, but they match the project’s purpose: to show there is a functional alternative to copper that also comes with a lower weight.

Weight and conductivity: the trade-off

One of the clearest benefits is the mass reduction. Carbon nanotube wire has a density of around 1.7 g/cm³, compared with copper at 8.9 g/cm³.

Even though its absolute electrical conductivity is lower - 7.7 million S/m (Siemens per metre) versus ~59 million S/m for copper - the specific speed per unit mass ends up in broadly similar territory. In electric cars, where every gram matters, that could prove decisive.

Why it could change everything

Another major advantage of this solution - beyond the weight savings - is sustainability. Manufacturing requires fewer metals, and nanotube fibres can be recycled with almost no loss of properties, helping to reduce emissions associated with production.

Key challenges still to overcome

Even so, several significant hurdles remain: producing long, consistent cables; limiting contact resistance between fibres (junctions between filaments create electrical losses that reduce overall system efficiency); and adapting the technology to safety and cooling standards. And, of course, costs are still high.

All the same, the promise is straightforward. If costs fall and reliability is confirmed, this copper-free electric motor technology will not just remain a laboratory experiment - it could reshape electric mobility with a solution that is lighter, efficient and more sustainable. And it does not have to be limited to cars.