Multifunctional Interface Engineering of Li13Si4 Pre‐Lithiation Additives With Superior Environmental Stability for High‐Energy‐Density Lithium‐Ion Batteries

ABSTRACT Considering the growing pre‐lithiation demand for high‐performance Si‐based anodes and consequent additional costs caused by the strict pre‐lithiation environment, developing effective and environmentally stable pre‐lithiation additives is a challenging research hotspot. Herein, interfacial engineered multifunctional Li 13 Si 4 @perfluoropolyether (PFPE)/LiF micro/nanoparticles are proposed as anode pre‐lithiation additives, successfully constructed with the hybrid interface on the surface of Li 13 Si 4 through PFPE‐induced nucleophilic substitution. The synthesized multifunctional Li 13 Si 4 @PFPE/LiF realizes the integration of active Li compensation, long‐term chemical structural stability in air, and solid electrolyte interface (SEI) optimization. In particular, the Li 13 Si 4 @PFPE/LiF with a high pre‐lithiation capacity (1102.4 mAh g −1 ) is employed in the pre‐lithiation Si‐based anode, which exhibits a superior initial Coulombic efficiency of 102.6%. Additionally, in situ X‐ray diffraction/Raman, density functional theory calculation, and finite element analysis jointly illustrate that PFPE‐predominant hybrid interface with modulated abundant highly electronegative F atoms distribution reduces the water adsorption energy and oxidation kinetics of Li 13 Si 4 @PFPE/LiF, which delivers a high pre‐lithiation capacity retention of 84.39% after exposure to extremely moist air (60% relative humidity). Intriguingly, a LiF‐rich mechanically stable bilayer SEI is constructed on anodes through a pre‐lithiation‐driven regulation for the behavior of electrolyte decomposition. Benefitting from pre‐lithiation via multifunctional Li 13 Si 4 @PFPE/LiF, the full cell and pouch cell assembled with pre‐lithiated anodes operate with long‐time stability of 86.5% capacity retention over 200 cycles and superior energy density of 549.9 Wh kg –1 , respectively. The universal multifunctional pre‐lithiation additives provide enlightenment on promoting large‐scale applications of pre‐lithiation on commercial high‐energy‐density and long‐cycle‐life lithium‐ion batteries.