Selective metal recovery: Innovating leaching of LFP-NMC cathode mixtures from spent lithium-ion batteries

Abstract

Lithium-ion batteries serve as the cornerstone of the shift towards sustainable energy and electric transportation. While the current emphasis of recycling plants is on electric vehicle batteries, there is a growing demand to expand the recycling industry to encompass smaller batteries, such as those powering electric bicycles—a sector experiencing rapid expansion. The chemical procedures essential for recycling these batteries may differ from those employed for electric vehicle batteries due to variations in material composition. In electric vehicles, the materials primarily originate from either NMC (LiNi_xMn_yCo_zO₂) or LFP (LiFePO₄) technologies, resulting in well-established compositions. Conversely, batteries from urban electric mobility comprise a blend of NMC and LFP technologies, leading to feeds with varying compositions. Therefore, the hydrometallurgical processes applied to these materials must successfully recover cobalt, nickel, manganese, and lithium, despite the presence of fluctuating and significant concentrations of iron—a common challenge in hydrometallurgy. This study will showcase how leveraging the physicochemistry of transition metals in the presence of phosphate can lead to the design of an efficient leaching process. This process selectively dissolves cobalt, nickel, manganese, and lithium from mixtures of NMC and LFP, yielding a sufficiently pure leachate.