Precision Dissolution of Salts for Solar-Driven Lithium Extraction from Brines

The lithium recovered from salt-lake brines constitutes a major component of the global lithium supply. However, conventional extraction processes typically exhibit low lithium recovery efficiencies and prolonged processing durations, whereas recently developed direct lithium extraction technologies are currently constrained by substantial freshwater and chemical consumption. To address these limitations, we introduce a fundamentally different lithium extraction strategy that isolates lithium salts from solid salt mixtures obtained from brines via selective dissolution in organic solvents rather than extracting lithium directly from the brines themselves. By leveraging the differential solubilities of the lithium salt and coexisting salts in volatile organic solvents such as ethanol and acetone, this extraction process eliminates the need for freshwater, uses minimal chemicals, and achieves high lithium recovery (∼95%). Notably, this method effectively addresses the longstanding challenge of boron and sulfate removal from brine matrices, thereby facilitating the production of lithium at high purity levels. Furthermore, coupling this process with interfacial solar evaporation accelerates the lithium extraction process and enables complete solvent recycling (>99%) using only solar energy. Our method presents a practical application of differential solubility principles for sustainable lithium extraction from brines and other sources.