Carbon nanotubes, also known as bucky tubes, are one-dimensional quantum materials with a special structure (the radial dimension is in the order of nanometers, the axial dimension is in the order of micrometers, and both ends of the tube are basically sealed).
Carbon nanotubes are mainly composed of several to dozens of layers of coaxial circular tubes of carbon atoms arranged in a hexagonal shape, including their lower-edge products carbon nanotube fiber for sale, carbon nanotubes membrane and CNT sheets. A fixed distance is maintained between layers, about 0.34 nm, and the diameter is generally 2 to 20 nm.
Due to their excellent electrical and mechanical properties, carbon nanotubes are considered ideal additive phases for composites. Carbon nanotubes have great application potential in the field of nanocomposites as reinforcing and conductive phases.
Carbon nanotube polymer composites are the first carbon nanotube composites that have been industrially applied. Due to the addition of carbon nanotubes with excellent electrical conductivity, the insulating polymer obtains excellent electrical conductivity. Depending on the base polymer, usually 3% to 5% loading can achieve the effect of eliminating static point accumulation. Experiments show that the addition of 2% carbon nanotubes can achieve the conductive effect of adding 15% carbon powder and adding 8% stainless steel wire. Due to the low addition amount and nanoscale size, the polymer will not reduce the mechanical and other properties of the polymer when it achieves good electrical conductivity and is suitable for injection molding of thin-walled plastic parts.
Carbon nanotubes have a very high surface area ratio. Depending on the diameter and degree of dispersion, the specific surface area of carbon nanotubes ranges from 250 to 3000m2/g. Coupled with excellent electrical conductivity and good mechanical properties, carbon nanotubes are required in the field of electrochemistry. It is an ideal material for making supercapacitor electrodes for electrochemical double-layer capacitors. Compared with ordinary dielectric capacitors, the capacitance of carbon nanotube capacitors increases from microfarads to farads. The capacitance of carbon nanotubes can reach 15 to 200 farads per gram. Capacitors of thousands of farads are currently produced.
Hydrogen energy contains a high value, does not pollute the environment, and is rich in resources. Carbon nanotube contains are considered to be an ideal energy source for the future. However, due to the difficulty of hydrogen storage, its use is greatly limited. At present, hydrogen storage methods mainly include metal hydride, liquefaction, high-pressure hydrogen storage, and organic hydride hydrogen storage. Although they each have certain advantages, they all have some disadvantages. Such metal hydrides are expensive and heavy; the safety of high-pressure hydrogen storage is affected. Carbon nanotube hydrogen storage is one of the application fields with great development potential. At room temperature and pressure, about two-thirds of the hydrogen can be released from carbon nanotubes, and it can be used repeatedly. Carbon nanotube hydrogen storage materials are used for hydrogen storage in fuel cell systems, which are of great significance to the development of electric vehicles. It can replace the current high-pressure hydrogen tank and improve the safety of electric vehicles. Research laboratory carbon nanotubes for hydrogen storage to achieve many research results. The hydrogen storage effects of single-walled carbon nanotubes of 4.2 w/%, lithium-doped multi-walled carbon nanotubes of 20 w/ %, and potassium-doped multi-walled carbon nanotubes of 14 w/ % were obtained, respectively. The US Department of Energy has established a commercial standard of 6.5w/%. That is, the hydrogen storage capacity is 65kg/m3, which can provide the energy required for electric vehicles to travel 500 kilometers. Fuel cells are widely used in mobile power sources (mobile phones, computers, etc.) household power sources, decentralized power stations, underwater robots, spacecraft, space stations, submarines (not relying on air propulsion) and other fields.
