NSERC-DFG SUSTAIN: ION-SIEVING CAPACITIVE EXTRACTION OF LITHIUM from Alberta Oilfield Brine towards Sustainable Supply Chain

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The increasing demand for lithium, especially related to the shift in the automotive industry towards electric vehicles, calls for alternative methods and additional supply sources to be exploited. Currently, the lithium extraction relies on hard-rock ores and continental brines, using evaporating and chemical technologies. However, the increasing demand for lithium expected in the next years and the concerns about the sustainability related to these methods requires to find alternative methods for this supply chain. Furthermore, less concentrated brines, where these technologies cannot be efficiently applied are available both in Canada, Germany, and more and would enable to provide a significant contribution to the lithium supply chain. Here, one of the main problems relies on the efficient separation of lithium ions from other competitive ions, such as sodium, magnesium, and more. Herewith we propose an innovative method based on ion-sieving capacitive deionization for the selective extraction of lithium from low-lithium concentrated brines, such as the Alberta oilfield brines. Capacitive deionization is a convenient method as it enables to store ions under low applied potentials and effectively release them upon discharge. For the purpose, a thin ion-sieving layer with nanopores that selectively enable the transport of lithium ions across the layer will be deposited on the surface of a heteroatom-doped carbon with very high surface area to store high amounts of lithium. The design of the carbon material and the ion-sieving layer is fundamental to achieve high selectivity and high lithium adsorption capacity. Eventually, we envision that this technology will enable to achieve continuous separation of lithium ions paving the way for innovation in the field of selective capacitive deionization towards a more sustainable lithium supply chain.