Lithium Recovery from Seawater by Electrodialysis using Ionic Liquid-based Membrane Technology

A new method for Li recovery from seawater by electrodialysis using a Li separation membrane with the ionic liquid PP13-TFSI was developed. Only Li ions can significantly permeate this membrane and thus pass from the anode side to the cathode side. Because the other ions (Na, Mg, Ca and K) in seawater are much less capable of permeating the membranes, Li becomes selectively concentrated on the cathode side. In the measurements of the ion concentration on the cathode side as a function of the duration of the applied dialysis voltage (2V), the Li concentration increased with time, reaching 24.5% after 2 h. The other ions in seawater did not permeate the membrane. This new recovery method shows good energy efficiency and is easily scalable. It should be suitable for use in seawater desalination plants and for the recycling of used Li-ion batteries.