Scientists Build First Electric Motor Without Any Metal

Korean researchers have successfully created the world’s first fully functional electric motor using only carbon nanotubes instead of traditional copper coils, marking a major step toward ultra-lightweight transportation systems.

The motor, built by a team at the Korea Institute of Science and Technology (KIST), not only runs without metal components but actually powers a toy car that travels at over half a meter per second. The achievement could revolutionize everything from electric vehicles to spacecraft by dramatically reducing weight while maintaining performance.

The breakthrough centers on solving a decades-old problem: how to make carbon nanotubes clean and conductive enough to replace copper in real-world applications. Using an innovative purification process inspired by liquid crystals, the researchers removed metal impurities that have long plagued nanotube technology while preserving the tubes’ exceptional electrical properties.

The Weight Problem in Electric Transportation

Every gram matters in modern transportation. Whether it’s extending the range of electric vehicles, improving drone flight times, or reducing spacecraft launch costs, weight reduction directly translates to energy savings and better performance.

Electric motor coils traditionally use copper because of its excellent electrical conductivity. But copper’s high density—8.9 grams per cubic centimeter—makes it a heavyweight component. Carbon nanotubes offer similar conductivity at just 1.7 grams per cubic centimeter, potentially cutting motor weight by more than 80%.

The challenge has always been manufacturing. Carbon nanotubes typically come contaminated with metal catalyst particles from the production process, which severely degrade their electrical performance and make them unsuitable for high-performance applications like electric motors.

Key Research Achievements:

• First functional electric motor using 100% carbon nanotube coils
• 133% improvement in electrical conductivity through new purification process
• Metal contamination reduced from 12.7% to less than 0.8%
• Specific performance nearly matching copper-based motors

Liquid Crystal Cleaning Revolution

The team’s solution draws inspiration from an unexpected source: liquid crystals, the technology behind LCD displays. They developed what they call the LAST (Lyotropic Liquid Crystal-Assisted Surface Texturing) process, which uses the unique properties of the “fourth state of matter” to clean carbon nanotubes at the molecular level.

“By developing a new concept of CNT high-quality technology that has never existed before, we were able to maximize the electrical performance of CNT coils to drive electric motors without metal,” said Dr. Dae-Yoon Kim of KIST, who led the research team.

The process works by dissolving carbon nanotubes in chlorosulfonic acid, creating a liquid crystal state where the tubes naturally align in orderly patterns. When this solution contacts water, it generates hydrochloric acid that chemically etches away iron catalyst particles while leaving the nanotube structure intact.

What makes this approach special is its precision. Previous cleaning methods often damaged the nanotubes themselves, undermining their electrical properties. The LAST process selectively removes only the impurities, preserving the hexagonal carbon structure that gives nanotubes their exceptional conductivity.

Beyond Press Coverage: The Performance Details

While initial reports focused on the motor’s basic operation, the study reveals crucial performance metrics that weren’t emphasized in early coverage. The purified carbon nanotube cables achieved electrical conductivity of 7.7 megasiemens per meter—a substantial improvement that brought them within striking distance of practical applications.

Perhaps more importantly, the researchers discovered that the specific rotational velocity—performance per unit weight—of their carbon nanotube motor was only 1.06 times lower than copper-based motors. This near-parity in weight-adjusted performance suggests that further improvements could make carbon nanotube motors competitive or even superior to traditional designs.

The team demonstrated remarkable stability, with their motor maintaining consistent performance for at least 60 minutes of continuous operation across different power levels. This reliability addresses a key concern about whether carbon nanotube-based systems could handle real-world operating conditions.

From Lab Bench to Race Track

The researchers didn’t stop at laboratory demonstrations. They built a complete scale model car powered by their metal-free motor and tested it on actual asphalt roads. The vehicle traveled 10 meters in 25 seconds, reaching the finish line marked by a red sculpture bearing the letters “KIST.”

This real-world testing revealed both the potential and current limitations of the technology. While the carbon nanotube motor successfully powered the car, copper-based motors still achieved higher absolute performance, reaching speeds of 1.35 meters per second compared to 0.52 meters per second for the nanotube version.

However, the weight advantage tells a different story. The carbon nanotube wires weighed just 78.75 milligrams compared to 379.08 milligrams for equivalent copper wires—a weight reduction that could prove crucial in weight-sensitive applications.

The Path to Practical Applications

The research team envisions applications far beyond toy cars. “Based on the innovation of CNT materials, we will take the lead in localizing materials such as conductive materials for batteries, pellicles for semiconductors, and cables for robots,” Dr. Kim explained.

The technology could prove especially valuable in aerospace applications, where every gram of weight saved translates to significant fuel savings or increased payload capacity. Electric aircraft, drones, and spacecraft could all benefit from lighter motor systems that maintain performance.

Electric vehicles represent another major opportunity. While the current technology doesn’t yet match copper’s absolute performance, the weight savings could extend vehicle range and improve efficiency—critical factors in electric vehicle adoption.

What Comes Next?

The researchers acknowledge that carbon nanotube motors aren’t yet ready to replace copper in all applications. But their work provides a clear roadmap for improvement. Further advances in purification techniques, nanotube structure optimization, and manufacturing processes could close the remaining performance gap.

The team plans to explore different types of carbon nanotubes that haven’t been fully characterized, optimize insulating materials for better thermal management, and refine motor designs specifically for carbon nanotube components.

Perhaps most intriguingly, the researchers believe that future electric vehicles and urban air mobility systems could be built entirely with carbon nanotube-based electrical systems. While that vision remains years away, this first metal-free motor represents a crucial proof of concept.

For an industry increasingly focused on sustainability and efficiency, the ability to build functional motors without traditional metals offers a glimpse of a lighter, more sustainable future—one where the materials themselves contribute to the solution rather than the problem.