By Zhao Shetao

Carbon nanotube, a new material discovered by a Japanese scientist Iijima Sumio in the 1990s, is a nano-scale seamless hollow tubular structure formed by curling graphitized carbon atoms. The production of carbon nanotube has a relatively high threshold. China’s carbon nanotube industry has walked out its infancy stage after constant development and over 20 years’ precipitation. Further efforts will be put into making breakthroughs in various application markets and the industry is poised to usher in a RMB100-billion market size in the coming decade.

Huge conductive agent market

   Carbon nanotube can be used as a conductive agent in the lithium battery industry for power batteries and digital batteries. Compared with traditional carbon black conductive agents, the use of carbon nanotube does not only greatly reduce the amount of addition, but also cut the amount of adhesive by around 50%.
   Carbon nanotubes have broad application prospects in touch screens, transistors, biomedicine, solar photovoltaic cells, tires, fuel cells, drug delivery, hydrogen storage, polymer materials, capacitors and composite materials, etc. The industry is expected to develop into a RMB100 billionmarket.
   China’s carbon nanotube conductive agent market will reach RMB4.5-billion scale by 2022, on the rapid development of power battery industry. The expanding application scale of new technologies such as high nickel anodes for lithium batteries, silicon-based anodes, and solid-state batteries is set to trigger explosive growth in the application of carbon nanotubes, which will have a RMB10 billion market size annually in the field of lithium batteries alone.
   Carbon nanotube companies, with a market value of RMB10 billion-size have emerged in China, such as Jiangsu Cnano Technology, and there are also many listed companies involved in the carbon nanotube business, including BTR, Dynanonic and Dowstoneetc, as boosted by the rising demand for conductive agent used in batteries. The rosy prospect of carbon nanotubes has attracted a lot of domestic capital to enter.
   In the coming five years, global demand for carbon nanotube conductive agent pastes (include 3-5% carbon nanotube and the rest is NMP) will keep a compound annual growth rate (CAGR) of 40.8%, with the total demand to reach 120 kt by 2022 and 190.6 kt by 2023.

More advanced research and development technology after six generations of polishing

   China’s production technology development of carbon nanotubes has experienced six generations. The commercialized forms of carbon nanotubes include films, continuous filaments, powders, and others. Among them, only carbon nanotube powder products can realize 100-ton-scale industrialization. According to the different numbers of layers and diameters, carbon nanotubes can be divided into single-layer and multi-layer carbon nanotubes. Among them, the performance of single-layer carbon nanotubes is the most superior, but the price of multi-layer carbon nanotubes is affordable, and is widely sold, produced and used as a result.
   Currently in China, the fourth generation carbon nanotube technology can achieve mass production of 100-ton-scale and only a few companies master the technology. Low-density and easy-dispersible carbon nanotubes have a specific surface area of 250-350m2/g, a bulk density of 0.01-0.02g/mL, and an average tube diameter of 8nm, with an average of about six-to-eight layers. As the product density is very low, and the production capacity per unit volume of the reactor is directly proportional to the product density, the utilization rate of the fluidized bed production reactor for carbon nanotubes is very low, and a lot of waste water is generated during the production process, causing greater environmental pressure and relatively high production costs of the fourth generation carbon nanotubes.
   The sixth generation carbon nanotube technology is a thin-walled carbon nanotube technology compatible with traditional multi-wall carbon nanotube production processes and equipment. Table 1 shows the specifications of the sixth generation thin-walled carbon nanotubes. The product bulk density is 0.05~0.07g/mL, easy to disperse, the catalyst rate can be adjusted between 9~40 times, the average tube diameter can be adjusted between 6.0~7.5nm, the average number of carbon nanotubes is about four layers, a variety of specifications can be formed according to different purposes, and the production process is simple, efficient and environmentally friendly.

   Carbon nanotube could only be synthesized in laboratories in China over 20 years ago, with prices at US$50-200/g and up to now, the production scale has grown into 100-ton, and the price per ton ranges from one hundred thousand to several hundred thousand yuan. It has successfully entered the industrial product market and is one of the few new materials industry with local independent intellectual property rights.
   At present, the technical level and product structure of domestic carbon nanotube are similar, generally showing low-level redundant construction. There are currently more than a dozen companies engaged in the production of carbon nanotube powder in China.
   Globally, companies producing carbon nanotubes are of small scales and their capital barriers are not high. In 2020, South Korea’s LG announced the construction plan of 1.7 kt/a multi-wall carbon nanotubes production line and entered the list of companies owning production capacity of 1-kt-scale, which is really rare. For the fine new material industry such as carbon nanotubes, the most important thing is the performance index and technical level of the product. A new generation of carbon nanotube products with original technology and higher cost-efficiency can lead the market.