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 Li₁₃Si₄@perfluoropolyether (PFPE)/LiF micro/nanoparticles are proposed as anode pre-lithiation additives, successfully constructed with the hybrid interface on the surface of Li₁₃Si₄ through PFPE-induced nucleophilic substitution. The synthesized multifunctional Li₁₃Si₄@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 Li₁₃Si₄@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 Li₁₃Si₄@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 Li₁₃Si₄@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.