Towards Sustainable Lithium-Ion Battery Anodes: Addressing the Critical Need for Graphite Recycling

Abstract

Graphite is the predominant anode material for all lithium-ion batteries (LIB) currently manufactured. However, despite comprising between 10 and 20 percent of a LIB's weight, graphite is not typically recycled. Graphite has a wide variety of applications outside of LIB, but the value of use in other applications is very low, so only recycling graphite back into anode material will be economically viable. Since graphite is such a stable substance, it should in theory be highly desirable for direct recycling back into anode material. As a result of this stability, several sources of graphite can become intermixed and impossible to separate later, posing a traceability issue. As is the case with cathode materials, there is currently no policy mandating the recycling of graphite.At the same time, graphite (natural) is on the EU's list of critical raw materials (98% imports), and the global supply of graphite for anode materials is entirely dominated by China. The production of natural and synthetic graphite has significant environmental costs, with recent studies indicating a CO2 footprint in the range of 10 to 30 kgCO2/kg graphite, which is significantly higher than what was previously reported in LCA literature. There is a need to establish processes for recycling this valuable material, as its demand is expected to increase dramatically over the next decade.In recent years, Vianode has developed a one-of-a-kind method for converting graphite concentrates from LIB production scrap and end-of-life batteries (black mass) back into anode-grade graphite for use in new LIB. Using a high temperature purification stage, impurities and flaws in graphite can be effectively removed and a purity of over 99.99% can be attained. Cell testing reveals that recycled graphite can achieve the same properties as virgin graphite, including outstanding reversible capacity, first cycle efficiency, fast charge capability, and cycle life. The results indicate that graphite recycling should be implemented as soon as possible to lessen the EU's reliance on graphite imports and significantly reduce the environmental impact of anode materials in LIB.