Extraction Of LiCl From Low-Purity Chlorides Through Solid Electrolyte Towards High-Purity Li₂CO₃ Production

Lithium carbonate (Li₂CO₃) plays a crucial role in advancing state-of-the-art lithium-ion batteries (LIBs) for efficient energy storage. The primary source of lithium is lithium-rich brines, which have complex compositions. Conventional extraction processes from brines involve cumbersome methods that often lead to emissions and/or large volumes of wastewater. To address these environmental challenges, a novel and eco-friendly lithium extraction process under ambient pressure is necessary. In this project, we developed an electrolytic process utilizing a NASICON-type solid-state electrolyte (LATP) to extract lithium chloride from low-purity sources at a temperature of 380 °C. To reduce the melting points of the lithium sources, ZnCl₂ was introduced as a fluxing agent. The electrolytic process effectively separated Li⁺ from other coexisting ions, but resulted in their mixture with Zn²⁺. Subsequently, purification and carbonation processes were employed to produce high-purity Li₂CO₃ (98.9 %). We also obtained high-purity Zn(OH)₂ (>99.9 %) as a value by-product. Despite the formation of color centers that caused the LATP disk to change from white to black during the electrolytic process, it exhibited sufficient ionic conductivity for successful lithium extraction. Our environmentally friendly approach offers a promising pathway for efficient and sustainable lithium extraction, contributing to the advancement of LIB technology for energy storage applications.