Lithium extraction from high-sodium raw brine with Li0.3FePO4 electrode

Abstract

It is highly promising to directly extract lithium from high‑sodium raw brine to meet the increasing demands of Li. However, efficient separation of Li/Na is a new challenge faced by the lithium extraction process. Based on the electrochemical deintercalation/intercalation lithium extraction method, the Li/Na separation ability of the Li1-xFePO4 electrodes with different Li content was systematically investigated. It demonstrated that the Li0.3FePO4 electrode exhibits better ion selectivity ability and higher adsorption capacity. Through the lithium extraction from artificial brine (main compositions: Li+ 0.5 g·L−1, Na+ 92 g·L−1) by using Li0.3FePO4 electrode, the results shown that the Na/Li mass ratio decreased from 184 in the brine to 1.33 in the anolyte with the Li/Na separation coefficient reached 138, and the Li+ concentration in anolyte increases to 1.32 g·L−1 with the current efficiency reaches 82.23%. Furthermore, the Li0.3FePO4 electrode displayed good cycling stability, and the capacity retention rate exceeded 90% after 100 cycles.