Recycling of lithium from used batteries by liquid-liquid extraction in an ionic liquid medium

A sustainable supply of lithium is essential for the development of modern electrical devices. These devices are based on lithium-ion batteries (LIB), the key element of these LIB is lithium. Recycling is a strategic axis on which the supply of lithium is based in an environmentally and economically sustainable manner. In this context, during this thesis project, our efforts were directed towards the study of lithium recycling by liquid-liquid extraction (LLE). Ionic liquids (ILs) have been used to replace toxic organic solvents. The present work has two practical and theoretical objectives: (i) the development of a new LLE system for the extraction of lithium by combining extractant and IL and (ii) the understanding of the mechanisms of lithium extraction from aqueous media (acids and bases) in an IL medium with different types of extractants (neutrals and acids). Our results showed that it is relatively difficult to design a LLE system capable of directly extracting lithium from a LIB leachate. For this reason, we proposed to extract lithium at alkaline pH, where most of the cations present in the leachate are already removed. The optimal extraction system under these conditions is that using β-diketone in LI. We have demonstrated that this extraction solvent meets most of the requirements of an ideal system for lithium extraction involving IL. (author)