Artificial Graphite Powder for Lithium-Ion Batteries
Graphite, named for the Greek word “graphein,” is an allotrope (form) of carbon that is soft and pliable. It is extremely stable, electrically and thermally conductive, chemically passive, and lighter than aluminum. Unlike diamond, which is metastable and much more expensive, high-quality natural or synthetic graphite is highly sought after for use in lithium-ion batteries, electric vehicle production, and other applications that require the highest possible purity.
Typically, natural graphite requires extensive beneficiation to remove unwanted materials and achieve the required level of purity. This is due to the fact that graphite, being soft, easily "marks" and coats the particles of other minerals found in the rock it is mined from. This creates a mineral concentrate that must be further processed, either by repeated regrinding and flotation to purify the material, or by acid leaching using hydrofluoric or hydrochloric acids depending on the type of gangue present in the rock.
The graphite used in battery applications is typically impregnated with a phenolic resin to make it resistant to the acidic solutions used during processing and battery manufacture. At GAB Neumann, the impregnated graphite is sourced from Western Europe and is optimized for a specific application, assuring that it is free of structural defects or large pores.
TA Instruments’ HR rheometer allows graphite manufacturers to quickly and accurately measure the powder shear strength and cohesion of their graphite prior to incorporation into a battery slurry. This information can be used to reduce aggregates, achieve flow, and minimize anode defects in the final slurry, resulting in higher processing yields and improved performance for their products.
