Pre‐Formation of LiF‐Rich Interfaces on Prelithiated Si/C Anodes for High‐Energy Lithium‐Ion Batteries

ABSTRACT Prelithiation is effective for compensating active lithium‐ion (Li + ) loss in silicon (Si)‐based battery electrode materials. However, owing to the dynamic growth of the solid electrolyte interface (SEI), capacity fading remains the biggest challenge for the industrialization of Si electrodes. To address this problem, a novel ether‐based prelithiation reagent was rationally designed by exploiting the weak solvent–solute coordination and the competitive reduction mechanism among electrolyte components. Precise regulation of the Li + solvation structure enhanced Li + transport during prelithiation, achieving an exceptional initial Coulombic efficiency (ICE) of ∼100% for the Si/carbon (Si/C) anode after performing contact prelithiation for 2 min. Furthermore, the lithium fluoride (LiF)‐rich interface with high mechanical toughness was pre‐formed to assist in the formation of a stable SEI film by controlling the lowest unoccupied molecular orbital (LUMO) energy and binding energy of the prelithiation reagent, thereby improving the half‐cell cycle performance. Consequently, the ICE of the full‐cell incorporating the prelithiated Si/C anode increased by 40% compared with that containing as‐received materials, and the corresponding energy density was 551.2 Wh kg −1 based on the electrode material after 3 cycles. Furthermore, theoretical calculations combined with in situ characterization techniques confirmed the strong potential of the contact prelithiation design strategy for large‐scale industrial applications.