Electrodialysis as a Method for LiOH Production: Cell Configurations and Ion-Exchange Membranes

Lithium hydroxide (LiOH) is rapidly becoming the main precursor for layered oxide cathodes used in lithium ion batteries. Current hydrometallurgical method for LiOH production uses substantial amounts of chemicals and creates wastes, leaving behind a negative environmental footprint. Electrodialysis is emerging as a more sustainable technology for LiOH production, effectively eliminating the conventional chemical addition step and its subsequent waste management. Additionally, hydrogen is generated as a by-product during the electrodialysis process. Various configurations of the electrodialysis cell have been employed to maximize the energy efficiency of the process and the purity of the LiOH product. Nonetheless, this review found that there is a lack of concerted effort in developing ion exchange membranes specific for LiOH production. Current membrane technologies are not tailored to LiOH production, with limited selectivity to lithium in relative to other monovalent cations, as well as relying heavily on harmful perfluoroalkyl (PFA)-based polymeric membranes. In this review, special attention is given to the state of the art in the testing and development of membranes, i.e., cation and anion exchange membranes, bipolar membranes, as well as novel membranes that are potentially low-cost, non-fluorinated, lithium-selective with high chemical stability and mechanical robustness. '' This review article provides an overview of the state-of-the-art electrodialysis for battery-grade LiOH production. The different cell configurations, benchmark commercial membranes and ion transport mechanisms is analysed. A survey on the latest advances in Li+-selective membranes to target Li salt applications and describe current shortcomings to boost the technology is also provided.'' image