A research team in South Korea has developed the world’s first fully functional electric motor constructed entirely without metal components. Replacing traditional copper coils with carbon nanotubes (CNTs), this breakthrough marks a major step toward ultra-lightweight transportation systems. The CNT motor demonstrates a 133% improvement in electrical conductivity and weighs 80% less than conventional designs.

Lightweighting remains a key challenge in the development of electric vehicles, drones, and spacecraft. Lighter components not only reduce energy consumption but also increase battery efficiency and extend operational range. The newly developed motor, created by researchers at the Korea Institute of Science and Technology (KIST), successfully powers a toy car at speeds exceeding half a meter per second, showcasing its potential in practical applications.

This innovation stems from a novel approach to improving the purity and performance of CNTs. Carbon nanotubes are nanoscale tube-shaped structures composed of carbon atoms arranged in a hexagonal pattern. These materials are significantly lighter than metals and offer exceptional electrical conductivity, mechanical strength, and thermal properties.

One of the major challenges in CNT motor development has been contamination. During production, metal catalyst particles often remain embedded in the nanotubes, impairing their electrical performance. The KIST team addressed this issue using a specialized purification technique known as the Lyotropic Liquid Crystal-Assisted Surface Texturing (LAST) process. By dissolving the CNTs in chlorosulfonic acid, the researchers created a liquid crystal phase where the nanotubes align uniformly. Exposure to water then triggered a chemical reaction that removed the embedded iron catalyst without damaging the CNT structure. This reduced metal contamination from 12.7% to below 0.8%.

The resulting CNT cables achieved an electrical conductivity of 7.7 megasiemens per meter. In performance tests, the specific rotational velocity of the CNT motor was slightly lower than that of a copper-based motor, but the weight difference was dramatic. While copper wires used in test motors weighed 379.08 milligrams, the CNT wires weighed only 78.75 milligrams.

To demonstrate the motor’s capabilities, researchers built a scale-model car powered by the CNT motor and tested it on real asphalt. The vehicle traveled 10 meters in 25 seconds. Although it was outpaced by a copper-motor counterpart, the efficiency-to-weight ratio highlights the promise of CNT technology in lightweight applications.

Beyond electric motors, this CNT innovation could extend to other fields including batteries, semiconductor pellicles, and robotic cables. With the ability to localize and scale up these advanced materials, the team at KIST aims to drive broader adoption of carbon nanotube-based components across future high-performance systems.

By Impact Lab