State of research on Li-Ion battery recycling

Abstract

This keynote represents the international research activities on the subject of Li battery recycling. These can in principle be diversified into modules which essentially follow the mechanical pretreatment and sorting, a thermal conditioning, wet-chemical or pyrometallurgical objectives. In addition to the economic perspective, modern and sustainable processes address in particular the aspect of environmental footprint and resource efficiency, which is reflected in the minimized use of chemicals, energy needs and process-steps. The lecture presents the most important module combinations studied already and gives a qualitative assessment of the respective alternatives. The seven main aspects to consider the state of recycling include different characteristic process features, profitability considerations or political dispositions. 1. Safety and revenue first: Recycling paths always follow the guiding principle of a safe process design in terms of both environmental and human health issues. On the other hand, a recycling process has to meet the demands of economically beneficial product generation. This is why most recycling processes aim to recover the Li-battery components with a high value fraction, e.g. Cobalt, instead of considering the high mass-fraction components. 2. Technically, no limit foreseen, all is energy and cost driven: In the field of Li-Ion battery recycling, there is a wide range of possible recycling paths and process constellations investigated, depending on process aims and recovery ambitions and resulting in different by-products and target elements. A recovery rate of 100% will not be realized for financial reasons. 3. Metal value will never pay off recycling cost and trend for cheaper material deterioration: Because of the prevalent imbalance of actual value generated in a recycling process and costs for the process, with regard to energy and human resources, there is a tendency to accept disturbing elements. 4. Changing chemistries require flexible and robust recycling tools: Since Li-Ion battery compositions are evolving over time there is the need to adjust the recycling processes to new technical solutions in order to guarantee a continuous sustainable resource management. 5. Pyro- and hydrometallurgical processes are competing and complementary: Comparing two fundamentally different metallurgical strategies concerning the recycling of Li-Ion recycling leads to several beneficial and detrimental characteristics. So, scientists combine available tools in order to develop the best possible process design. 6. Germany, EU and worldwide redundant research, no initiative to tie up the best: Networks can help organizing different approaches to avoid a doubling of research issues 7. Political legislation has low Recycling Efficency (RE) without “punishment” strategy in place: The base of a successful and environmental aware recycling path, being valid also for ignoble metals, is the creation of political incentives, making the recovery indispensable. Moreover, Lithium in particular, is embedded in a complex context, in which the necessity of Li-driven batteries increases, whereas the recycling of the element Li is neglected. In contrast to Pb in lead accumulators, Lithium is less valuable, noble, stronger diluted and is of a chemically variable chemistry. Besides, the surrounding legislative and logistical factors are not forcing the recovery of Lithium. Still, from the technical realization perspective Li-Ion cells can be and partially are recycled with high RE.