KIST's copper-free electric motor could transform electric mobility

Copper is one of the key materials used in electric motors, but what if an electric motor could be made without copper? It would be revolutionary, and that possibility has just taken a major step closer to reality.

Researchers at KIST (the Korea Institute of Science and Technology) have built a copper-free electric motor prototype, replacing metal coils with wiring made from carbon nanotubes.

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

KIST copper-free electric motor testing

KIST has already tested the concept using a small-scale car fitted with a prototype of this copper-free electric motor, demonstrating that the solution is viable. The motor reached 3420 rpm at 3 Volts, which may seem low alongside the 18 120 rpm achieved by an equivalent copper electric motor.

During testing, the scale model travelled 10 metres in 25s using a 3 V battery. That may sound modest, but it matches the project's aim: proving that a working, lighter alternative to copper exists.

Weight reduction is one of its most significant benefits. Nanotube wiring has a density of around 1.7 g/cm³, compared with 8.9 g/cm³ for copper. Although its absolute electrical conductivity is lower - 7.7 million S/m (Siemens per metre), versus ~59 million S/m for copper - its mass-specific speed is at a similar level. In electric cars, where every gram matters, this could prove decisive.

Why it could change everything

Beyond the lower weight, sustainability is another major advantage of this approach. Manufacturing requires fewer metals, while carbon nanotube fibres can be recycled with almost no loss of their properties, cutting the emissions associated with production.

Challenges for carbon nanotube wiring

Important hurdles still need to be addressed, including producing long, uniform cables; contact resistance between fibres (connections between filaments create electrical losses that reduce the system's overall efficiency); and meeting safety and cooling standards. Costs also remain high, of course.

Even so, the potential is clear. If costs fall and reliability is proven, this copper-free electric motor technology could move beyond the laboratory and revolutionise electric mobility with a lighter, more efficient and more sustainable solution. It would not necessarily be limited to cars either.