Li1.5Al0.5Ge1.5(PO4)3 membrane electrodialysis for lithium enrichment

Highly purified LiOH is a common raw material of cathode active materials of lithium-ion batteries. Its demand is rapidly increasing with the fast development of the electric vehicles. The traditional enrichment process of LiOH relying on water evaporation requires a lot of energy. Here, we demonstrate the ability of NASICON-type Li1.5Al0.5Ge1.5(PO4)3 membrane electrodialysis to enrich the LiOH aqueous solution with a low concentration. This Li1.5Al0.5Ge1.5(PO4)3 membrane electrodialysis could extract 99.7% and 96.5% of Li+ in 0.1, and 0.01 M LiOH feed solution, respectively, into 1 M LiOH receiving solution. And the transmembrane resistance between feed solution and receiving solution increased by 37.4, 389.5, and 964.6 Ω cm2, compared to the value for 1 M of LiOH feed solution as the feed solution concentration decreased to 0.1, 0.01 and 0.001 M, respectively. This quantitative assessment method for the resistance variation is crucial to the potential separation application of Li1.5Al0.5Ge1.5(PO4)3 membrane electrodialysis in salt-lake brine.