Researchers at the Institute of Nanoscience and Materials of Aragon and the IMDEA Materials Institute in Spain have developed a new carbon nanotube fiber that could eventually replace copper wiring in electric vehicles (EVs), drones, and aircraft. The findings, published in the journal Science, detail a chemical doping process that improves nanotube conductivity by a factor of 17 while preserving the fiber's structural integrity.
At ambient temperature, the treated fibers achieve about 40% of copper's electrical conductivity. On a weight-adjusted basis, their specific conductivity exceeds that of aluminum, and at peak values, they surpass aluminum's absolute conductivity. The fibers weigh roughly one-sixth as much as copper while offering approximately five times the tensile strength. Earlier versions of these fibers were recognized for being tough and lightweight but lacked sufficient current-carrying capacity, making the conductivity gain the key breakthrough.
The improvement came from treating the fibers with tetrachloroaluminate (AlCl4-), a compound that acts as a dopant by introducing charge carriers without disrupting the atomic lattice. Preserving structural integrity is critical because a conductor that breaks down in service has no practical value. The researchers note that this method addresses a long-standing difficulty in the field.
Modern EVs carry a significant amount of copper, especially in thick high-voltage wiring bundles. Replacing part of that copper with a lighter material reduces overall vehicle mass and extends driving range. Lower resistivity at operating temperatures also cuts heat buildup, improving efficiency and safety. In drones, reducing cable mass translates directly into longer flight times, and for aircraft developers, weight reduction yields outsized returns in fuel savings and payload capacity.
The material also demonstrates reliable performance in dry conditions and acceptable moisture tolerance—properties that are important for meeting transportation certification standards. On specific conductivity, the metric manufacturers prioritize most, the treated fibers have entered territory that warrants serious engineering attention.
Remaining challenges include scaling up production to achieve consistent fiber quality, ensuring compatibility with existing hardware, and establishing a cost profile competitive with conventional metals. Recycling infrastructure for these materials will also need to be developed. Many automotive firms, such as Ferrari N.V. (NYSE: RACE), are watching to see whether this new material becomes commercially available at scale and at price points that make the switch from copper economically viable.
