Antisolvent‐Regulated Anionic Coordination Enabling Stable Li Metal Anode in Urea‐Based Electrolyte

The fabrication of NO₃ ^- anion-participating solvation sheaths to derive inorganic-rich solid electrolyte interphase (SEI) layers is critical for enhancing the stabilization of lithium metal batteries (LMBs). However, the application of LiNO₃ salt is limited by its low solubility and the challenge of controlling NO₃ ^- coordination, primarily due to its high donor number. Herein, we demonstrate an antisolvent-enhanced anionic coordination effect in urea-based LiNO₃ electrolytes for boosting the cycling stability of LMBs. We find that the incorporation of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) into these electrolytes enhances the interaction between the NO₃ ^- anion and urea-based solvent to Li⁺ in the solvation sheath, resulting in an increase in ion-pair formation. This also induces a transformation of the NO₃ ^- anion from a monodentate to a bidentate coordination configuration, facilitating preferential nitrate reduction at the anode interface. The optimized electrolyte formulation demonstrates remarkable cycling stability in lithium metal anode, achieving 6000 h of operation in a Li||Li cell and a high Coulombic efficiency of 99.6% in a Li||Cu cell. In full-cell testing, Li||LiFePO₄ cells (N/P = 3) maintain 88% capacity retention after 100 cycles at 0.2C.