Li separation by electrodialysis in hydrometallurgical processing of Li-ion batteries: a review of the state-of-art

The recovery of valuable metals from spent Li-ion batteries (LIBs) has become crucial to mitigate issues related to critical metals extraction and scarcity. The process of separating and purifying Li from LiBs leach solution through electrodialysis (ED) is considered a promising approach for separating monovalent cations from divalent cations and anions but remains challenging due to the complexity of these solutions and process parameters meeting economic and technical requirements. This review highlights advances in ED technology for LIBs recycling. ED is high electricity-consuming when processing high concentration leaching solutions; on the other hand, reduces the amount of chemical consumption in comparison to common techniques such as solvent extraction or precipitation. Monovalent-IEM has demonstrated highly selective for Li ions, while complexing agents (e.g. EDTA or DTPA) can transform in a pH-dependent reaction divalent cation into anions that are highly rejected by cationic ion exchange membranes. Nonetheless, challenges such as membrane fouling and long-term degradation persist. This review aims to provide guidance for future advancements and improve the efficiency of LiBs recycling.