LiMn2O4 Nanoparticles In Situ Embedded in Carbon Networks for Lithium Extraction from Brine via Hybrid Capacitive Deionization

Highly selective and efficient extraction of lithium from brine is considered a promising strategy to alleviate the imbalance between supply and demand of lithium resources. However, it is still challenging for lithium ions (Li+) recovery from brine. In this work, LiMn2O4 nanoparticles embedded in situ in carbon networks (LMO-C) derived from metal–organic frameworks by incomplete calcination have been developed for lithium extraction from brine via the hybrid capacitive deionization (HCDI) process. The adsorption capacity of the obtained LMO-C for Li+ is 3.5 mmol g–1, while the separation factor reaches 24.5 at a high Mg:Li ratio of 20. The extraction and insertion of Li atoms in the LiMn2O4 lattice were visually confirmed. In addition, it is found that the synergistic effect between the LMO and the carbon networks is retained in the surface of LMO-C, and the above effect effectively promotes the migration of Li+ and the sustainability of the HCDI process. This work is believed to provide a guidance for the design and synthesis of high-performance HCDI materials for the practical lithium extraction from brine.