Lithium extraction from water lithium resources through green electrochemical-battery approaches: A comprehensive review

The growing market demands for large-scale applications of lithium such as lithium-ion batteries increase the significance of its production. Land lithium resources are drastically decreasing; thus, lithium extraction from water lithium resources involving salt-lake brine and seawater has a growing tendency owing to its merits of low cost and abundant reserves. Lithium extraction from water lithium resources, especially those with high Mg/Li ratios, is challenging. Among all kinds of aqueous lithium-extraction methods, the electrochemical-battery approach is considered the most promising one as a result of its excellent lithium selectivity, high insertion capacity, low energy consumption, high reversibility, and ecofriendliness. The present work reviews the advantages and challenges of current electrochemical-battery systems involving lithium manganese oxide and lithium iron phosphate systems. The effects of several parameters and relevant mechanisms are discussed, including applied voltage, ionic concentration, pH, time, and coexisting ions. We stress that a combination of the electrochemicallithium-recovery process with a desalination process enables the highly efficient and economical extraction of lithium from low-concentration solutions. Currently available electrochemical batteries still suffer from problems of low stability and high cost of raw materials. Future research should focus on the enhancement in the battery-system stability, process optimization, and reduction of operating costs.