Efficient lithium extraction from seawater by electrodialysis with a flexible LATP/PVDF membrane

Ocean is abundant in lithium resource, showing great potential to meet the rapidly growing demand for lithium-based energy storage systems. Electrodialysis-based lithium extraction is an environmentally friendly and energy-efficient technology. Nevertheless, exploration of Li + separation membranes with high selectivity and superior mechanical properties remains a challenge. Herein, we present a flexible composite membrane based on ceramic Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) lithium ion conductor and polyvinylidene fluoride (PVDF) polymer in an all-water electrodialysis system for efficient lithium extraction. LATP/PVDF membranes with different compositions and thicknesses as well as operation conditions are systematically investigated with simulated seawater. It was first discovered that Li + may release from LATP particles when subjecting to a strong electric field, leading to overestimation of Li + selectivity. Lithium mass balance between seawater feed and enriched solutions was proposed to verify the performance authenticity. The system was then employed to extract Li + from natural seawater to demonstrate its industrial viability. As a result, Li + concentration in enriched catholyte is 87 times higher than the natural seawater with a low energy consumption of 8.3 Wh g Li −1 . In addition, LATP/PVDF membrane shows superior separability for interfering ions with Li + /Na + , Li + /Mg 2+ and Li + /Ca 2+ selectivity of 22,040, 64,235 and 15,336, respectively. This study provides a method for efficiently extracting lithium from seawater, offering an important approach for ensuring sustainable lithium supply.