The general trend of replacing traditional graphite with high-performance carbon nanotubes
All battery performance improvements must be accompanied by the upgrading of materials. Therefore, in recent years, conductive agent materials have gradually been upgraded from traditional conductive carbon black to conductive graphite, VGCF, CNT, and graphene. On December 17, [Li Yuanheng General Title] 2020 High-tech Lithium-Electric Vehicle Annual Meeting continued at the Hyatt Hotel in Shenzhen Airport. Yan Yan, Director and Deputy General Manager of Tiannai Technology, gave a keynote speech entitled 'Development of Conductive Agents and Application of Conductive Agents for New Generation of Single Wall Carbon Tubes'. Yan Yan introduced that Tinatech’s carbon tube and graphene conductive materials have been developed to the fifth generation. Each generation of products has a conductivity that is 50% higher than the previous generation, and the cost does not exceed 20%. Tina Technology’s product upgrade direction follows a basic rule. One is to continuously reduce the diameter of the carbon tube and increase the bottom surface area; the second is to continuously improve the purity; the third is to improve the dispersion of the carbon tube. In OM/SEM analysis and testing, Tiannai Technology’s FT2000 single-walled carbon nanotubes have no visible agglomerates and are better dispersed; in SEM/TEM analysis and testing, FT2000 single-walled carbon nanotubes have a bundled structure with an average tube diameter. At 2.8nm, the number of tube wall layers is 1~2. The length of the initial carbon tube can be up to 200um, and the length of the carbon tube can be maintained at about 7.6um after dispersion, providing a higher aspect ratio and conductive network. In terms of volume resistivity testing in different applications, in the NCM test, the volume resistivity of FT2000 is slightly lower than that of SWCNT. And the test results under different systems show that FT2000 can replace the multi-wall LB116 product 1:8 (different positive electrode systems will be slightly different) Yan Yan concluded that the fifth-generation FT2000 series products of Tiannai Technology can be used in silicon carbon anodes. :3 to 1:10 instead of carbon black, the first cycle efficiency and rate performance are slightly improved; the overall conductive agent application trend is to use finer carbon nanotubes. The more FT2000 added, the better the SiOx cycle; the single-walled carbon tube mixed with 10% LB216, the battery performance is basically the same, and it has a higher cost performance. Considering the dispersibility and viscosity stability of FT2000, it is recommended to use it with multi-walled carbon nanotubes. Yan Yan said that the company currently has an annual production capacity of 1,500 tons of powder and 30,000 tons of conductive paste, and plans to expand its production to 50,000 tons next year.