Scalable Carbon Nanotube Fibers Achieve High Conductivity in Spain

This article is based on an official press release from the IMDEA Materials Institute and a peer-reviewed study published in Science. This article summarizes publicly available elements and public remarks.

Breakthrough in Ultralight Carbon Nanotube Fibers Promises to Reshape Aerospace and EV Wiring

Researchers in Spain have achieved a major materials science breakthrough by developing a scalable manufacturing process for carbon nanotube (CNT) fibers that rival the electrical conductivity of traditional metals at a fraction of the weight. Published in the journal Science on April 23, 2026, the study outlines a novel chemical doping method that increases the electrical conductivity of carbon nanotubes by a factor of 17.

Led by the IMDEA Materials Institute in Madrid, the research was conducted in collaboration with the Instituto de Nanociencia y Materiales de Aragón (INMA), the University of Zaragoza, Universidad Autónoma de Madrid, and Universidad Politécnica de Madrid. According to the official press release, the resulting material achieves a conductivity of up to 24.5 megasiemens per meter (MS/m) at room temperature. While this represents approximately 41 percent of the absolute conductivity of copper, the new CNT fibers are roughly six times lighter.

For industries constrained by the weight of traditional electrical wiring, such as aerospace, drone manufacturing, and electric vehicle (EV) production, this development paves the way for ultra-lightweight, high-strength alternatives to copper and aluminum.

The Science Behind the Breakthrough

Intercalation Doping Explained

Carbon nanotubes, which are essentially rolled-up sheets of graphene, possess excellent theoretical electron mobility. However, according to the research team, their practical conductivity has historically been limited by a low number of free charge carriers. To overcome this hurdle, the scientists utilized a process known as intercalation doping.

The researchers exposed commercially available, highly aligned double-walled carbon nanotube fibers to a gas containing tetrachloroaluminate (AlCl₄⁻) and excess chlorine for a period of 24 hours. The AlCl₄⁻ ions diffused into the interstitial channels between the nanotube walls, rather than entering their hollow cores. Because of the concentric arrangement of the nanotubes, these gaps are large enough to accommodate the dopant without distorting the underlying carbon structure.

“AlCl₄⁻ provides a large doping effect without increasing weight excessively, compared to other dopants we have studied,” explained lead author Ana Inés de Isidro Gómez.

This dopant acts as a noncovalent electron acceptor, drastically increasing the number of free charge carriers and boosting the material’s conductivity 17-fold without compromising its mechanical integrity.

Industry Impact and Applications

Aerospace and Electric Vehicles

Reducing the weight of electrical wiring remains a critical bottleneck in modern engineering. Heavy copper wiring limits the range of electric vehicles and reduces the payload capacity of aircraft. By replacing heavy copper harnesses with ultralight CNT fibers, manufacturers could significantly extend battery ranges and improve overall vehicle efficiency. In the aerospace and drone sectors, every gram saved in wiring translates directly to longer flight times and reduced energy consumption.

“This is the first time that researchers have produced results with CNT fibres demonstrating sufficient performance… to offer a realistic industrial alternative,” stated Dr. Juan José Vilatela, Principal Investigator at IMDEA Materials.

Power Distribution

Beyond transportation, the high strength-to-weight ratio of the new fibers makes them highly attractive for power grid infrastructure. According to the published data, the doped CNT fibers are up to five times stronger than conventional overhead power cables, which are currently limited by the sheer weight of the metal lines they must support.

Current Limitations and Future Challenges

Moisture and Heat Sensitivities

While the breakthrough is significant, the research team acknowledges current limitations that must be addressed before widespread commercialization. The doped fibers exhibit instability when exposed to humid air. However, the researchers demonstrated that when protected by a standard commercial polymer cable sheath, the fibers successfully retained 80 percent of their conductivity over a five-day testing period. Improving long-term environmental stability remains the team’s next major objective.

Additionally, independent experts have pointed out potential thermal challenges. James Elliott, a researcher at the University of Cambridge, noted that dopants in such systems can sometimes degrade or dissipate if the cable heats up significantly during high-power transmission.

“It’s a brilliant result – it’s very exciting from lots of application points of view,” remarked independent expert James Elliott.

AirPro News analysis

We observe that the true commercial value of this breakthrough lies in the metric of “specific conductivity”, the ratio of a material’s conductivity to its density. While copper remains more conductive in absolute terms (~60 MS/m compared to the CNT fiber’s 24.5 MS/m), copper is exceptionally heavy. The new CNT fibers reach a specific conductivity of 17,345 Siemens-meter squared per kilogram, exceeding both copper and aluminum. For the aviation and EV sectors, where weight is the primary enemy of efficiency, a material that conducts electricity better than copper on a per-pound basis is effectively a “holy grail.” If the IMDEA team can solve the moisture and thermal degradation issues, this technology could fundamentally alter how electrical harnesses are engineered over the next decade.

Frequently Asked Questions (FAQ)

What is specific conductivity?

Specific conductivity measures how well a material conducts electricity relative to its weight (conductivity divided by density). A material with high specific conductivity is ideal for applications where keeping weight low is just as important as transmitting power efficiently.

Why replace copper wiring?

Copper is an excellent conductor but is very heavy. In electric vehicles and aircraft, the weight of copper wiring harnesses drains batteries faster and burns more fuel. Lighter alternatives allow for longer ranges and higher payload capacities.

Are these carbon nanotube fibers ready for commercial use?

Not yet. While the manufacturing process is scalable, the fibers currently lose some conductivity when exposed to moisture or high heat. Researchers are working on protective sheathing and stabilization techniques to make them viable for long-term industrial use.

Sources: Science (DOI: 10.1126/science.aeb0673), IMDEA Materials Institute Press Release