Double-walled carbon nanotubes are used as fuel cell catalyst carriers.

Double-walled carbon nanotube films have excellent electrical and optical properties, so they are potential replacements for ITO. The method of removing water molecules and oxygen molecules adsorbed in the double-walled carbon nanotube film by laser irradiation is used to increase the light transmission performance of the film, and the improvement of the light transmission performance increases the energy conversion efficiency of the double-walled carbon nanotube solar cell.

Because carbon atoms in carbon nanotubes adopt sp2 hybridization, compared with sp3 hybridization, the s orbital component in sp2 hybridization hybridization is relatively large, which makes carbon nanotubes have high modulus and high strength.

Carbon nanotubes are as hard as diamond, but have good flexibility and can be stretched. Among the commonly used reinforced fibers in the industry, it is called "super fiber".