Mining Lithium from Seawater

Unlike conventional land-based resources for lithium (Li), which are concentrated in a few geographic locations (e.g., closed-basin brines, pegmatites, lithium clays, and zeolites), seawater provides a massive and evenly distributed global Li reserve (230 billion tons), albeit at low (<1 parts per million) concentrations. As global Li consumption continues to rise over the next few decades, the development of cost-competitive technologies for Li extraction from seawater warrants intense research. In this issue of Joule, Steven Chu and colleagues introduce an electrochemical methodology to selectively remove Li from seawater. This selective removal is accomplished by exploiting the differences in electrochemical potentials for the Li⁺ and sodium (Na)⁺ insertion/extraction reactions, and their diffusion activation barriers in the FePO₄ framework of the ordered olivine MeFePO₄. This work demonstrates the possibility of energy-efficient Li extraction from seawater at relatively high rates with long-term stability by using the electrochemical ion insertion/extraction in battery electrode materials.