Highly Selective Electrochemical Lithium Extraction from Brine by Bipolar Electrode Method

The extraction of lithium from brine is crucial for the sustainable development of energy technologies, particularly due to the rapid expansion of the lithium-battery market. However, extracting lithium selectively from low concentration brines that contain other co-existing ions presents a significant challenge. This necessitates new approaches to enhance the selectivity of lithium extraction. In this study, we introduce a method using the bipolar electrode process for direct electrochemical lithium extraction from a 1:100 molar ratio of lithium to other co-cations. The bipolar electrode mechanism facilitates lithium intercalation and deintercalation, while an ion-selective membrane positioned centrally allows the selective passage of lithium ions, inhibiting other cations. This technique effectively isolates lithium ions from multiple co-existing metal ions. Remarkably, this method achieved a separation factor of approximately ~1500, even with a two-fold higher molar concentration of co-cations in the brine. X-ray diffraction analysis indicated that ionophores with ionic sites play a pivotal role in the selective extraction of lithium. This work presents a promising new approach for extracting lithium from complex solutions containing various metal ions.