Highly selective lithium recovery from seawater desalination brine using Li₂TiO₃ membrane-coated capacitive deionization

Selective lithium (Li) recovery from seawater-based resources is challenged by low Li concentrations and the presence of competing ions such as Na⁺, K⁺, Mg²⁺, and Ca²⁺. This study presents an innovative approach by integrating capacitive deionization (CDI) with a titanium-based lithium-ion sieve (LIS) membrane-coated cathode and an anion exchange membrane (AEM)-coated anode for enhanced Li recovery from seawater desalination brine (SWDB). The cathode was fabricated using Li₂TiO₃ (LTO) adsorbent through rolling pressing and dip coating methods. Characterization confirmed the successful fabrication of the LTO membrane-coated electrode. The performance of the LTO-AEM-CDI system was evaluated using simulated SWDB through an adsorption-rinsing-desorption operational mode. The results indicated that the rinsing stage plays a crucial role in significantly enhancing Li selectivity. A 10-cycle stability test demonstrated the system's reliability, maintaining the active Li selectivity (ALS) consistently above 100 across all cycles. This research highlights the potential of combining LIS, membrane technologies, and CDI for effective Li extraction from seawater-based resources.