Industrial Recycling of Lithium-Ion Batteries—A Critical Review of Metallurgical Process Routes

Research for the recycling of lithium-ion batteries (LIBs) started about 15 years ago. In recent years, several processes have been realized in small-scale industrial plants in Europe, which can be classified into two major process routes. The first one combines pyrometallurgy with subsequent hydrometallurgy, while the second one combines mechanical processing, often after thermal pre-treatment, with metallurgical processing. Both process routes have a series of advantages and disadvantages with respect to legislative and health, safety and environmental requirements, possible recovery rates of the components, process robustness, and economic factors. This review critically discusses the current status of development, focusing on the metallurgical processing of LIB modules and cells. Although the main metallurgical process routes are defined, some issues remain unsolved. Most process routes achieve high yields for the valuable metals cobalt, copper, and nickel. In comparison, lithium is only recovered in few processes and with a lower yield, albeit a high economic value. The recovery of the low value components graphite, manganese, and electrolyte solvents is technically feasible but economically challenging. The handling of organic and halogenic components causes technical difficulties and high costs in all process routes. Therefore, further improvements need to be achieved to close the LIB loop before high amounts of LIB scrap return.