Lithium recovery from diluted brine by means of electrochemical ion exchange in a flow-through-electrodes cell

Abstract

Lithium is becoming an important raw material due to the expansion of the market of lithium-ion batteries, required for electric vehicles and for stationary energy storage. The current method of lithium extraction is slow, inefficient and it has a strong environmental impact. In the last decade a new technology, called “electrochemical ion pumping”, based on the electrochemical selective capture of lithium cations from the brine, followed by the release of the ions into a so-called “recovery solution”, was proposed. In this work, we developed a flow-through-electrodes reactor, with which it was possible to capture lithium from a diluted solution containing 1 mM LiCl and 1 M NaCl, and concentrate it in a recovery solution. After 9 cycles, it was possible to produce 5 mL of 100 mM LiCl solution with 94% purity starting from more than one liter source solution. We have estimated the energy required by the process, finding that the major contribution is given by the hydraulic energy for pumping the electrolyte through the cell. The evaluation shows that the technology is economically feasible and it can enable a sustainable future production of lithium.