Trace Anion‐Receptor Chemistry for Stable Carbonate Electrolytes Toward Long‐Life Sodium Metal Batteries

Sodium metal batteries (SMBs) offer a promising route toward cost‐effective energy storage, but their operation in carbonate electrolytes is limited by coupled NaPF 6 degradation and interfacial instability. Trace moisture triggers salt hydrolysis and HF formation, continuously disrupting SEI/CEI chemistry and aggravating nonuniform Na deposition. Here, lithium 4,5‐dicyano‐2‐(trifluoromethyl)imidazol‐1‐ide (LiTDI) is introduced as a trace anion‐receptor additive to stabilize NaPF 6 ‐based carbonate electrolytes. Spectroscopic analyses and theoretical calculations reveal that LiTDI preferentially scavenges H 2 O/HF to suppress hydrolysis, while its electron‐rich N sites coordinate with PF 6 − to weaken Na + ‐anion coupling and reconstruct the solvation sheath, reducing aggregated ion pairs from 18.3% to 7.2%. Meanwhile, LiTDI‐derived interfacial reactions promote the formation of a NaF/Na 3 N‐rich SEI on Na metal and a compact F/N‐enriched CEI on cathodes, enabling homogeneous Na deposition and reduced interfacial polarization. As a result, Na||Na symmetric cells with 0.1% LiTDI achieve stable cycling for 400 h at 1 mA cm −2 , while the Na + transference number increases from 0.417 to 0.603. Na||Na 3 V 2 (PO 4 ) 3 full cells achieve exceptional durability with 80.36% capacity retention after 2000 cycles at 1 C, with a stabilized Coulombic efficiency of 99.87%. This work establishes a multifunctional anion‐receptor strategy for stabilizing NaPF 6 ‐based carbonate electrolytes and provides a practical avenue toward high‐durability SMBs.