A comparison of production routes for natural versus synthetic graphites destined for battery material

Abstract

Natural and synthetic graphites are used as battery material in many applications. Natural graphite can form in the earth’s crust at about 750 °C and 5000 Bar pressure, but very slowly (requiring millions of years). As the natural carbonaceous material (mostly plant fossils) which has been available to mother nature varies in physical and chemical properties, the mined natural graphites around the world have a wide range of characteristics. The natural impurities present at each mine site typically require multiple beneficiation steps to yield a salable natural graphite concentrate (80–90% purity) which then requires purification to achieve the battery material quality (~99.9% carbon content with minimum metallic impurities). In comparison, synthetic graphite can be produced from purer feedstock (typically petroleum-based) but requires a high temperature (~3000 °C) for the graphitization reactions to be completed within a reasonable time frame (days). Currently, the battery industry consumes a mix of natural and synthetic graphites; therefore, it is important to understand their respective production routes, competitive advantages, and limitations.