Grant: Alliance Grants

The past decade witnessed the rapid development of electric vehicles and the soar in demand for lithium as the most important energy metal. The security and sustainability of the lithium supply chain have become an increasing concern, especially with the geographically isolated distribution of Li mines. An estimated 10.6 million tonnes of lithium carbonate equivalent is found dissolved in oilfield brines In Alberta, which is groundwater coexisting with oil and gas. In typical oil production, Li-rich brine water is pumped to the surface and then reinjected into deep geological units after extracting the oil and gas. If the lithium can be extracted from the brine water before reinjecting the remaining brine, it could serve as a secure and sustainable lithium supply. The challenge lies in how to selectively extract lithium with a low concentration of 50 - 150 ppm in the presence of other metals with much higher concentrations, e.g., sodium, calcium, magnesium, and potassium. In collaboration with Dr. Paolo Giusto at the Max Planck Institute of Colloids and Interfaces, we propose an ion-sieving capacitive deionization (IS-CDI) technology to extract lithium sustainably from Alberta oilfield brine. Different from the traditional CDI technology, IS-CDI is highly selective to lithium because of the innovative ion-sieving layer based on 2D-covalent thin films with well-defined coplanar periodic pores. In future industrial production, the proposed IS-CDI unit will be integrated into the oil production process right before the reinjection of brine into the ground to minimize the operation cost. Compared to traditional hard rock lithium mining, the proposed IS-CDI is a much more sustainable solution, as no digging, crushing, or etching process is involved. Although IS-CDI consumes electricity in the lithium adsorption process, the same amount of electricity will be discharged in the lithium release process, resulting in minimal net electricity consumption. The successful deployment of the proposed international collaboration could diversify Alberta's economy, increase Canadian exports and provide a secure supply of Li to the German automobile industry.