Lithium aluminium titanium phosphate based ceramic composite membrane for selective lithium-ion separation via a scalable membrane-based electrodialysis process

The escalating global demand for lithium necessitates efficient extraction methods, particularly from natural sources such as brine. Herein, we report a novel, thin, and dense functionalised composite ceramic membrane that is employed in conjunction with electrodialysis technology for selective lithium extraction from salt lakes. This membrane exhibits high mechanical strength, low ionic impedance, and high lithium conductivity. The thin functional layer, ~20 μm-thick NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP) superionic conductor material, is deposited on high-strength and porous alumina membrane via a facile dip-coating method, providing structural stability for the composite membrane. The preparation and sintering processes of LATP-Al2O3 ceramic composite membrane were systematically studied and precisely controlled to improve its morphology and performance. A membrane-based electrodialysis set-up was designed specifically for lithium extraction demonstrated the remarkable performance of the composite-LATP membrane in separating lithium from magnesium-lithium solutions with a high Mg/Li ratio. The LATP composite membrane effectively reduced the Mg/Li ratio from 40 to 2.1 after three-stage electrodialysis. Moreover, the Li+ recovery reached 77.15% from the feed solution with an estimated power consumption of ~47.6 kWh per 1 kg of lithium carbonate. These findings have significant implications for the development of low-cost and environmentally friendly inorganic membrane separation technologies, which are important for promoting technological innovation in the lithium industry chain.