Researchers in China have developed a highly durable carbon nanotube fiber that sets new records in electrical conductivity. The double-wall carbon nanotube fibers (DWCNTFs), produced using an innovative “dry-jet wet spinning” technique, demonstrate unparalleled performance in both conductivity and strength.

This advanced spinning method significantly improves the alignment and density of the carbon nanotubes, resulting in DWCNTFs with an impressive electrical conductivity of 1.1 × 10⁷ S/m and the ability to carry a high current density of 8.0 × 10⁸ A/m². The fibers also boast a tensile strength of 1.65 GPa and toughness of 130.9 MJ/m³, making them some of the most robust carbon nanotube fibers ever produced.

The research team from Shenyang National Laboratory for Materials Science believes that these high-performance fibers have potential applications in critical industries such as aerospace and energy storage, where materials with excellent electrical conductivity, strength, and toughness are essential to replace traditional copper.

Innovation in Carbon Nanotube Fiber Production

Carbon nanotubes (CNTs) have long been recognized for their remarkable properties, but these benefits often diminish when CNTs are processed into larger fibers. Common methods like wet spinning can achieve high conductivity and reasonable strength, but the resulting fibers still fall short due to issues such as contact resistance and weak interactions between the nanotubes.

The alignment and packing of CNTs are crucial to optimizing fiber performance. Traditional production methods often lead to cracks and irregularities, which compromise the material’s integrity. To address these challenges, the researchers employed an advanced “dry-jet wet spinning” technique. This method, previously unused for CNTFs, enhances fiber quality by better aligning the polymers and reducing cracks, resulting in DWCNTFs with superior conductivity and strength.

The DWCNTFs developed by the team exhibit a high orientation factor of 0.994 and a density of 1.96 g/cm³, making them highly efficient and durable.

Unprecedented Conductivity and Durability

The study reveals that these DWCNTFs achieve a record-high electrical conductivity, reaching 86 percent of the conductivity of copper—a benchmark for excellent electrical performance. In addition to their impressive conductivity, the fibers maintain their tensile strength of 1.65 GPa, one of the highest recorded for fibers produced by this method.

Durability tests show that the fibers retain both their integrity and conductivity even after more than 5,000 bending cycles. This marks a significant advancement in carbon nanotube fiber technology, addressing previous limitations related to contact resistance and weak inter-tube interactions.

Implications for Advanced Materials

Currently, carbon fiber is the standard material for high-performance applications in sectors like aerospace, with companies like Airbus and Boeing using carbon fiber-reinforced composites in their aircraft modules. However, carbon nanotubes, also known as buckytubes, may soon surpass carbon fiber, offering even greater efficiency and opening up new possibilities in fields such as energy storage and space exploration.

Since their discovery in 1991, carbon nanotubes have been recognized as one of the most revolutionary materials, and ongoing research and optimization efforts continue to push the boundaries of their potential. China remains at the forefront of this cutting-edge research, contributing significantly to the advancement of carbon nanotube technology.

By Impact Lab