Scientists enhance next-generation battery manufacturing tech with new carbon nanotube powder.

A team led by Joong Tark Han at the Korea Electrotechnology Research Institute (KERI) Nano Hybrid Technology Research Center has developed an improved carbon nanotube (CNT) powder that resolves a problematic tendency for these hollow tubes of rolled-up graphene to clump together and resist thorough mixing with other materials in dry processing.

A dry process is a chemical-free manufacturing method where the active materials are mixed with a binder without employing toxic slurries of liquid solvents.

Dry processes are crucial in the production of next-generation lithium-sulfur and all-solid-state batteries, resulting in a more efficient product. In solid-state batteries, a direct, even application of carbon nanotube powder onto the current collector results in higher active material loading and improved performance.

"The dry process is environmentally friendly as it does not use toxic solvents, eliminates the need for solvent recovery, simplifies the process, and reduces production costs. That is why this technology is drawing attention from global electric vehicle manufacturers," said Han. "We're the first in the world to achieve the effective dispersion of CNTs to create conductive additives in dry processes. This technology will greatly aid in securing a significant technological lead in secondary battery technology."

Carbon nanotubes are a material with a tensile strength 100 times that of steel and possesses comparable electrical conductivity to copper. They are nanomaterials formed into long cylindrical tubes by one-dimensional hexagonal carbon chains more flexible and electrically conductive than carbon black, which is commonly used as a conductor in rechargeable batteries.

The addition of carbon nanotubes can significantly increase the energy density. However, they tend to clump and tangle with each other, resulting in a structure that does not mix well with other binders and active materials.

The breakthrough by Han and his team, though seemingly small, improves the manufacturing quality of high-capacity battery cells by making conductors from long carbon nanotubes, even in a challenging dry process.

Based on this achievement, KERI has filed a domestic patent application and is validating the "high-dispersibility CNT Powder production technology" for various applications, including high-capacity thick-film anodes/cathodes. Han's team expects that this achievement will attract attention from next-generation battery manufacturers and plans to identify and reach out to companies in need of the technology.