Lithium recovery using electrochemical technologies: Advances and challenges

Driven by the electric-vehicle revolution, a sharp increase in lithium (Li) demand as a result of the need to produce Li-ion batteries is expected in coming years. To enable a sustainable Li supply, there is an urgent need to develop cost-effective and environmentally friendly methods to extract Li from a variety of sources including Li-rich salt-lake brines, seawater, and wastewaters. While the prevalent lime soda evaporation method is suitable for the mass extraction of Li from brine sources with low Mg/Li ratios, it is time-consuming (>1 year) and typically exhibits low Li recovery. Electrochemically-based methods have emerged as promising processes to recover Li given their ease of management, limited requirement for additional chemicals, minimal waste production, and high selectivity towards Li. This state-of-the-art review provides a comprehensive overview of current advances in two key electrochemical Li recovery technologies (electrosorption and electrodialysis) with particular attention given to advances in understanding of mechanism, materials, operational modes, and system configurations. We highlight the most pressing challenges these technologies encounter including (i) limited electrode capacity, poor electrode stability and co-insertion of impurity cations in the electrosorption process, and (ii) limited Li selectivity of available ion exchange membranes, ion leakage and membrane scaling in the electrodialysis process. We then systematically describe potentially effective strategies to overcome these challenges and, further, provide future perspectives, particularly with respect to the translation of innovation at bench-scale to industrial application.