Removal and Recovery of Metallic Impurities from Lithium-Ion Battery Black Mass: A Kinetically Optimized Multi-Modal Approach

Achieving true circularity for the critical materials utilized in lithium-ion batteries requires advancements in the state-of-the-art for battery recycling. Fine battery scrap (“black mass”) contains residual metallic contaminants (Cu, Al, Fe, etc.) as well as non-metallic impurities (e.g., plastics) that reduce recycled material performance and may ultimately induce catastrophic cell failure. Successful direct recycling of black mass relies on the effective removal and recovery of these metallic contaminants under conditions that do not adversely impact the cathode material. In the present work, we demonstrate a multi-modal purification approach based on tailored alkaline chemistry to selectively leach metallic contaminants from a matrix of black mass. Process conditions have been rationally tuned at the pre-pilot scale to minimize processing time while maximizing the purity of the resulting output product. We utilize a diverse suite of purification strategies—including oxidation, chelation, magnetic separation, flotation, and membrane extraction—in a single batch system to selectively target, remove, and recover impurities from battery black mass. We have developed a circular offtake strategy for the reclaimed Al impurity product, and have also identified further treatment optima for the resulting cathode material to promote optimized surface conditions for subsequent direct recycling treatment. Herein, we present on the development of this method from idealized bench-scale optimization experiments to scale-up and demonstration in an industrially relevant reactor system. We report on the efficacy of purification utilizing a series of real-world battery black mass samples that have been variably pre-processed. We also demonstrate successful integration this method with upstream and downstream direct recycling processes. Finally, we address the reclamation of metallic impurities as valuable side-products from our purification method. Our optimized multi-modal approach represents a promising strategy to purify battery black mass fines under conditions that both retain the engineered value of the cathode product and enable recovery/reuse of the metallic contaminants, thereby maximizing overall value to the critical materials supply chain.