A review on lithium extraction by electrochemical electrode deionization technology

In the past few decades, with the rapid development and wide application of lithium-ion battery, the demand for lithium resources has increased significantly. Lithium resources mainly exist in Salt Lake, so extracting lithium from Salt Lake is of great significance. Since Mg²⁺ and Li⁺ have similar ionic radius and chemical property, the main difficulty in extracting lithium from Salt Lake is the separation of Mg²⁺ and Li⁺. Current techniques in the common use of separating Mg²⁺ and Li⁺ from Salt Lake mainly include the extraction method, adsorption method, and membrane method. Electrochemical electrode deionization (EEDI), also known as capacitive deionization in its early days, is a promising water desalination technology that has the advantages of environmental friendliness, low cost, low energy consumption, and convenient electrode regeneration. EEDI is primarily used for desalination, but its working principle indicates that it can also be used for element enrichment. Currently, a large number of works have used EEDI for Mg²⁺/Li⁺ separation and Li⁺ enrichment. This work aims to review the research progress of EEDI for lithium extraction, focusing on its working mechanism, key materials (electrode materials or membrane materials), achieved performance, and prospects for future development. This work will help promote the development of EEDI technology in the field of Mg²⁺/Li⁺ separation.