Formation of Quasi‐Decoupling Interface on Li‐Metal Anodes in High Donor Electrolyte

ABSTRACT Li‐metal batteries (LMBs) emerge as the “holy grail” of energy storage owing to their high energy density contributed by the Li‐metal anode. In this study, lithium ditelluride (Li 2 Te 2 ) is introduced as an electrolyte additive, yielding lithium telluride (Li 2 Te) on the Li‐metal anode (LMA), establishing a quasi‐decoupled interface that reduces electrolyte decomposition. To create an aggressive and high Gutmann donor number environment, dimethyl sulfoxide (DMSO) is employed as a solvent in the electrolyte. Lithium nitrate (LiNO 3 ) is initially used as an additive to protect the LMA surface from DMSO; however, the Li‐metal interface modified by LiNO 3 cannot block the electron transfer between high donor DMSO and LMA. Owing to its low formation enthalpy (−101.94 kJ mol −1 ), Li 2 Te 2 spontaneously converts to Li 2 Te upon contact with Li, effectively blocking electron transfer from DMSO through its large bandgap (E g = 2.549 eV) and minimal Bader charge transfer (−0.044 |e|). Li 2 Te establishes a quasi‐decoupled interface that electronically isolates Li from the DMSO. In addition, Li 2 Te exhibits strong lithiophilic and Li + conductive characteristics, which drive the dendrite‐free electrodeposited morphology. Introduction of Li 2 Te 2 additive in DMSO‐based electrolyte enhances the cycling stability of LMA in half‐cells and full‐cells, whereas the cells fail without Li 2 Te 2 .