FePO4-Zn/Pt hybrid battery system for the electrochemical extraction of Li+ from salt lake brine with high Mg2+ concentrations

This study presents a FePO 4 -Zn/Pt hybrid power battery system designed for lithium extraction from salt lake brines. Initially, the FePO 4 -Zn battery is utilized for lithium intercalation to form LiFePO 4 , which is subsequently reassembled into a LiFePO 4 -Pt battery for lithium deintercalation. As a result, a Li + -rich aqueous solution, free from interfering metal cations, is obtained. The system eliminates the need for ion-exchange membranes, as the Pt electrode remains separated from the brine, thereby preventing contamination by impurity cations. When applied to a brine containing 0.25 g/L Li + and 73 g/L Mg 2+ , followed by desorption in a solution of 0.25 g/L Li + , only a minimal amount of Mg 2+ was transferred to the lithium chloride solution after two cycles, achieving effective lithium extraction and enrichment with an efficiency of 80.6%.