Lithium extraction by extractant confined in Pickering emulsion.

Li, Enze; Li, Zelong; Xia, Qiancheng; Zhang, Feiyu; Liang, Zhangqi; Xu, Zhaozan; Gao, Guandao; Li, Hu et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

The global energy transformation towards electrification and decarbonization urgently requires a sustainable lithium supply. However, current solvent extraction technology suffers from extractant dissolution and low efficiency. Herein, we develop an oil-in-water (O/W) Pickering emulsion with high stability using amphipathic SiO<sub>2</sub> nanoparticles to confine tributyl phosphate (TBP) extractant within the oil phase for enhancing lithium extraction from salt-lake brine. Resultantly, the Pickering emulsion achieves a lithium recovery of 91.7% with Li-Mg separation factor (β<sup>Li</sup><sub>Mg</sub>) of 101.9 after only three-stage extraction and Li<sup>+</sup> mass transfer rate (k) of 4.57 × 10<sup>-8 </sup>m/s, greatly outperforming the traditional TBP system (52.8% recovery, β<sup>Li</sup><sub>Mg</sub> = 12, k = 7.50 × 10<sup>-9 </sup>m/s). We propose that the tiny gaps between SiO<sub>2</sub> particles serve as Li<sup>+</sup> transport channels, in which the interfacial electric field generated by surface charges of SiO<sub>2</sub> particles and the confinement effect within these gaps synergistically enhance Li<sup>+</sup> dehydration and diffusion.