Multi-chamber bipolar membrane electrodialysis for high-purity lithium hydroxide production: A case study

In recent years, lithium has emerged as a critical material in the field of new energy technologies, driven by the rapid growth of the battery industry. A significant portion of the world's lithium is found in salt lake brines, notably in South America's Lithium Triangle, China's Qinghai-Tibet Plateau, and the western United States, making their extraction a critical focus for the battery industry. This study addresses a key challenge in producing battery-grade lithium hydroxide from Lagkor Tso Lake—excessive chloride ion concentrations in the final product, by using a multi-chamber bipolar membrane electrodialysis (BMED) process. By utilizing the chlorine ion-blocking effect of the multi-chamber design, the chloride ion content in the lithium hydroxide solution was significantly reduced. Specifically, a four-compartment BMED system lowered the chloride ion content to 31–54 % of the levels observed in a traditional three-chamber system, while a five-chamber system achieved a reduction to as low as 67 %. This work provides an innovative and efficient approach for producing battery-grade lithium hydroxide from brines, offering a simplified and effective solution to a long-standing challenge in salt lake lithium extraction.