Selective sorbents for recovery of lithium ions by hybrid capacitive deionization

Lithium is a critical element due to its use in lithium-ion batteries, required for electric vehicles and stationary energy storage devices. Various approaches have been applied to extract it from the available resources. One of the developed lithium-capturing methods is hybrid capacitive deionization (HCDI), where the cathode is made of spinel-type material. This paper presents our study on the most effective Li, Mn, and Ti spinel-type materials, for which we analysed their structure, efficiency for lithium capturing, and energy consumption in the HCDI system. We found spinel with Li:Mn:Ti ratio of 1:3:0.15 to be the best material for lithium recovery. The natural geothermal water was applied for testing lithium recovery by HCDI equipped with the investigated material. By applying the asymmetrical electric mode, the lithium capturing efficiency reached near 80% with 8 min. The separation factors for other cations such as sodium, potassium, calcium, magnesium, and strontium were over three-times smaller.