Fig. 1: Schematic of electrolyte-oriented interfacial chemistry and SEI formation for Na metal stability.

Dipole-dipole interaction between electron-rich O atom (δO-) in G2 and electron-deficient H atom (δH+) in MPE that alters electron density distribution in solvent-solvent complex and facilitates C-F bond cleavage for spontaneous and fast surface passivation. The dense NaF-dominant primitive SEI protects Na metal at an early stage and ensures the reversible cycling of Na metal under harsh conditons.