Anion-derived Solid Electrolyte Interphase Realized in Usual-Concentration Electrolyte for Li Metal Batteries

Constructing anion-derived solid electrolyte interphase (SEI) by recruiting anions into the solvation sheath of Li+ is extremely conducive to restrain the dendrite growth of Li metal anode. However, the presence of anions in the solvation sheath of Li+ is severely hindered by the solvents with strong coordinating ability in conventional electrolyte. Herein, we boost the content of anions in the primary solvation sheath of Li+ by employing a solvent with low donor number, 2-methyltetrahydrofuran, inducing an anion-derived SEI. As a result, the Li∥Cu cells show a high average Coulombic efficiency (> 99