Lithium Extraction through Pulsed Electrochemical Intercalation Method

Stanford researchers have developed a new electrochemical method for extracting lithium from low concentration sources such as seawater. Despite containing 5000x more lithium than land and brine-based resources, the presence of sodium (4x that of lithium) in seawater has made clean extraction of lithium difficult. By using a TiO₂-coated FePO₄ to intercalate lithium into the electrode, researchers were able to achieve high selectivity for lithium. In cases where the Li/Na molar ratio is greater than 10^-3, the diffusion barrier and thermodynamic intercalation potentials yield ~100% Li selectivity over Na. However, for seawater or water with lower Li/Na ratios, the pulse sequence developed here yields Li selectivity ~1.8 x 10⁴ over Na. The pulse sequence additionally helps to stabilize the crystal structure, prolonging the electrode lifetime. This improved lithium extraction method is critical as the demand for lithium-ion batteries increases in the coming decades.

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