Significance of Fluorine Chain‐Driven Active Sites for Enhanced Selective Lithium Recovery

Abstract Fluorine (F)‐based sorbents show promise for selective lithium (Li) extraction, yet the role of fluorocarbon chain length on optimizing Li adsorption remains unclear. Here, fluorocarbon structures in hydrogels are precisely tailored with chain lengths of six, nine, and twelve units (labeled as F6, F9, and F12). The results reveal that Li‐F interactions can be strengthened by extending fluorocarbon units, leading to enhanced Li adsorption. The terminal F‐sites on longer fluorocarbon chains exhibit cumulative electron polarization, endowing 1.7 to 2.3‐fold stronger binding energies. As a result, Li adsorption capacity increases from 23.2 to 65.3 mg g −1 , and the distribution coefficient (K d ) rose from 27.2 to 104.7 mL g −1 from F6 to F12. 2D‐NMR spectroscopy further identifies the structure‐function relationship, in which electron‐withdrawing effects are amplified on the elongated chains, creating fluorine‐rich microenvironments. To further improve site accessibility and mass transport, hydrogels are engineered with hierarchical large pores and introduced nanobubble‐enrichment, increasing the adsorption capacity to 85.45 mg g −1 . Continuous recovery experiments using Li‐containing wastewater yield Li 2 CO 3 with considerable profits ($5,516–31,906 per ton), demonstrating the economic viability of the approach. This work highlights the significance of fluorocarbon chain length driving fluorine‐active sites for selective sorbents, providing pivotal insights for advancing sustainable Li extraction.