Chinese nanotube wire rivals copper in conductivity and could someday be used in space

[Nan Yang]

Nanotubes are tiny cylindrical molecules made up of carbon atoms linked together in a hexagonal shape. Photo: Shutterstock

Chinese nanotube wire rivals copper in conductivity and could someday be used in space​

• Superstrong, ultrathin carbon fibres, also known as buckytubes, could be used in array of hi-tech sectors, from energy storage to aerospace

Dannie Pengin Beijing
Published: 6:00pm, 3 Aug 2024

Chinese scientists say they have created a superstrong carbon nanotube wire with record-breaking ability to conduct electricity that could someday be used in aerospace and other critical industries.

Nanotubes are cylindrical molecules made of carbon atoms linked together in a hexagonal shape with a diameter as small as 1 nanometre. By comparison, a strand of human hair is about 100,000 nanometres thick.

Carbon nanotubes are 100 times stronger than steel pieces of the same size, with only a fraction of their weight.

But figuring out how to bind tens of thousands of these tiny tubes together into a visible and usable fibre has proved to be a challenging task – one that took the research community more than two decades to achieve.

To overcome these challenges, scientists from the Shenyang National Laboratory for Materials Science improved on a common fibre formation method known as “dry-jet wet spinning” to ensure maximum preservation of the nanotubes’ properties.

The team was led by researchers Liu Chang and Hou Pengxiang of the Shenyang institute, which is under the Chinese Academy of Sciences in Liaoning province. Their findings were published in a paper for in the peer-reviewed journal Advanced Functional Materials last month.

The resulting fibres “have a record high electrical conductivity”, according to the paper. The authors say the conductivity of their wire is 86 per cent that of copper, an excellent metal conductor of electricity.

These fibres exhibit other desirable properties, such as a tensile strength of 1.65 Gigapascals (GPa) – which is “among the highest” for fibres produced by the same method, the researchers said.

The researchers also tested the performance of the fibres and found their integrity and conductivity were well preserved after more than 5,000 bending cycles.

According to Gao Enlai, an associate professor at Wuhan University’s department of engineering mechanics, carbon fibre sets the benchmark for high-performance materials used in hi-tech sectors such as aerospace. For example, many Airbus and Boeing aircraft modules are made of carbon fibre-reinforced composites.

Gao, who was not involved in the Shenyang team’s research, said carbon nanotubes would be far superior to the carbon fibre used now, unlocking potential for very broad applications, such as energy storage and space elevators.

Since their discovery in 1991, carbon nanotubes, also known as buckytubes, have been hailed for their potential to be one of the most innovative materials of the 21st century.

For more than 20 years, researchers have been working to optimise their manufacturing process, according to Gao, who believes that China is a front runner in the field, both in terms of academic research and process optimisation.

As part of their innovation on the spinning method, the Shenyang team designed and built a new apparatus capable of aligning the nanotubes in specific positions and making them more compact.

“Individual carbon nanotubes, if not properly aligned and assembled to ensure the whole wire is very smooth and dense, can affect the overall performance of the final product,” Gao said.

In June, Gao and his collaborators, including leading expert Zhang Jin of Peking University, published a paper in Science journal about how they produced carbon nanotube fibres with a dynamic strength of up to 14 GPa, much stronger than any known fibre material.

However, he noted that there remained a global hurdle in turning these laboratory breakthroughs into economically viable and competitive commercial products, and that his team was working to scale up the production of their ultrastrong fibres.

Last November, an international team of researchers from universities in the United States, Europe and Asia was granted more than US$4 million to advance the understanding of carbon nanotube synthesis and its potential for more sustainable production of industrial materials.

“We already know how to make these materials with the right properties; now we have to understand how to make them efficiently and sustainably, which requires a completely different level of understanding of the underlying processes,” Matteo Pasquali, a member of the international research team and professor at Rice University in Texas, said in an interview last year.





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