Sorting lithium-ion battery electrode materials using dielectrophoresis at frequencies of up to 500 kHz

Abstract

Lithium-ion batteries (LIBs) are common in everyday life and the demand for their raw materials is increasing. Additionally, spent LIBs should be recycled for achieving a circular economy and supply resources for new LIBs or other products. Especially the recycling of the active material of the electrodes is in the focus of current research. Existing approaches for the recycling (e.g., pyro-, hydrometallurgy or flotation) still have their drawbacks, such as the loss of material, generation of waste, or lack of selectivity. In this study, we test the behavior of commercially available LiFePO₄ and two types of graphite microparticles in a dielectrophoretic high-throughput filter. Dielectrophoresis is a volume dependent electrokinetic force that is commonly used in microfluidics but recently also for applications that focus on enhanced throughput. In our study, graphite particles show significantly higher trapping than LiFePO₄ particles. The results indicate that nearly pure fractions of LiFePO₄ can be obtained with this technique from a mixture with graphite.