Sustainable Electrochemical Extraction of Lithium from Natural Brine for Renewable Energy Storage

Abstract

An electrochemical reactor for the extraction of lithium from natural brine has been designed. It comprises two 3D porous packed bed electrodes and a porous separator filled with electrolyte. The electrodes are filled with conducting petroleum coke particles covered respectively with LiMn 2 O 4 selective to lithium ions and polypyrrole selective to anions. It operates in two steps: First, the porous electrodes and the separator are filled with natural brine to extract Li + and Cl − by intercalation and adsorption. Then, after rinsing with water the reactor is filled with a dilute LiCl recovery solution and LiCl is recovered by reversing the electrical current. A mathematical model for the reactor comprising the Nernst-Planck equation and the battery intercalation model has been developed. The model was solved using the finite element method under the COMSOL Multiphysics environment in order to obtain the electrostatic potential and the ion currents and concentrations across the system. Unlike the asymmetric LiMn 2 O 4 /activated carbon super-capacitor, in the lithium extracting reactor the total LiCl concentration decreases in the extraction step and increases in the recovery step. A good agreement between the experimental and simulated potential difference vs. time at constant current validates the model of the reactor.

Electrochemical Methods for Lithium Recovery: A Comprehensive and Critical Review

“…The whole process (capture plus release) was analyzed, [ 154 ] in which a reactor with small dead volume was designed and studied. Several cycles of capture/release were performed, by capturing from a source solution with 1 × 10 −3 m of LiCl and releasing it into 5 mL of recovery solution, initially composed by 100 × 10 −3 m KCl.…”

“…The total W e, i was evaluated from the experimental data, [ 153 ] so that the contributions W irr, i could be calculated. [ 154 ]…”

“…W T for the experiment reported in ref. [154] was 6.1 Wh mol −1 . It was noticed that the use of NaCl rather than KCl in the recovery solution affects the reversible work needed by the extraction: by using KCl, 85% of energy is spared.…”

“…In ref. [154], the improved reactor design allowed the pumping energy to be decreased down to 1.9 kWh mol −1 for the extraction from 1 mM solution. In this situation, the pumping energy consumption widely exceeded the required electric energy (6.1 Wh mol −1 [154]), which could be neglected in the total cost evaluation.…”

Continuous Lithium Extraction from Aqueous Solution Using Flow-Electrode Capacitive Deionization

“…The greatest sources of lithium exist in seawater and brackish water. Therefore, lithium extraction from brackish water and seawater has received much attention for economical and stable lithium production [5][6][7][8][9][10][11][12][13]. Mantia group introduced lithium recovery from brines using ion exchange process [12,13].…”