Electrochemical extraction of lithium (ELE), as a green lithium extraction technology, is of great significance to the exploitation of lithium resources in salt lakes and the sustainable development of the new energy industry. However, the low efficiency and competition of impurity ions limit its large-scale application. In this paper, the current research progress is reviewed from the viewpoint of reaction tank design, electrode material modification, reaction tank process parameter optimization and multi-technology coupling. Additionally, through in-depth research and exploration of these key issues, it is expected to improve the efficiency of electrochemical lithium extraction, reduce energy costs, and promote the practical application and popularization of lithium extraction technology in salt lakes. Finally, this paper discussed the existing challenges and outlooks to improve the performance of ELE, meeting the rising global demand for lithium sources.

Cost-effective and efficient lithium extraction technology is vital to foster the growth of lithium industry. This paper proposed a novel approach for the high value utilization of spent LiFePO₄ (S-LiFePO₄) in the field of lithium extraction from salt lakes was proposed using spent LiFePO₄ (S-LiFePO₄) as raw material. The anode, made from spent LiFePO₄, is prepared via a sintering process, while FePO₄, obtained through chemical oxidation, is used as the cathode. Compared with commercial LiFePO₄, this system not only reduces the cost but also greatly shortens the preparation time of FePO₄ (only about 10min is required). And the electrochemical extraction system had a favorable lithium extraction capacity (29.25 mg/g) from actual brine, reducing the Mg/Li ratio from 61.4 to 0.8. This study not only achieved the low-cost preparation of electrode materials and facilitated the large-scale implementation of this process, but also proposed a high-value comprehensive utilization strategy for lithium-ion batteries recycling.

Thick electrodes greatly enhance lithium extraction capacity. However, with the increase of active substances loading, the traditional thick electrodes are more hydrophobic, severely limiting the utilization of active substances. Hence, a sulfonation process to functionalize thick electrodes was applied to enhance their wettability (~45 mg·cm⁻¹) in brine. Experimental and theoretical results show that the lithium extraction capacity of thick electrodes can be significantly improved by enhancing the electrodes hydrophilicity. At 0.8 V, the S-PVDF electrode's capacity for lithium extraction in simulated brine (41.72 mg·g⁻¹) significantly surpassed the PVDF electrode (35.72 mg·g⁻¹), and it also performed well in actual brine (28.8 mg·g⁻¹). The Mg²⁺/Li⁺ ratio in actual brine dropped from 65 to 0.37, achieving effective magnesia‑lithium separation. This method offers a novel approach to developing high-efficiency lithium extraction thick electrodes.