A multifunctional interphase strategy to repel solvent molecules for stabilizing interfacial chemistry

Multifunctional graphene-sulfonate interphase enables interface stabilization. • Solvent-repelling sulfonate groups induce Li + solvation and a LiF-rich SEI. • Fixed anions create continuous Li + pathways and accelerates transport kinetics. • The artificial interphase accommodates volume variation and remains intact. • The Si@GS anode achieves 91.6% ICE and 2400 mAh g −1 after 100 cycles at 0.2 A g −1 . Interfacial instability in lithium-ion batteries originates from the ion transport, mechanical deformation, and solvation mediated interfacial reactions. However, integrating these functionalities within a single interfacial layer remains a challenge. Here, a multifunctional artificial interphase is constructed via a coating strategy that integrates fast Li + transport, mechanical buffering, and solvent exclusion. The fixed-anion framework provides continuous Li + coordination sites to facilitate efficient interfacial ion transport, while the conformal artificial interphase accommodates volume fluctuations and preserves structural integrity. More importantly, the artificial interphase intrinsically repels solvent environment and suppressing solvent induced side reactions. This regulation redirects interfacial chemistry toward the formation of a LiF-rich, inorganic-dominated solid-electrolyte interphase (SEI). A silicon-based anode is employed as a model platform to demonstrate the effectiveness of this strategy, delivers a high initial Coulombic efficiency of 91.6% and maintains a reversible capacity of 2400 mAh g −1 after 100 cycles at 0.2 A g −1 . Furthermore, the Si@GS//LiFePO 4 full cell exhibits excellent cycling stability, achieving a capacity retention of 88.4% after 400 cycles at 1C. Mechanistic studies reveal the multiscale regulation of interfacial processes, spanning molecular-scale solvation modulation, nanoscale SEI chemistry reconstruction, particle-level coating integrity, and electrode-level Li + transport kinetics. This work establishes a multifunctional interphase design strategy featuring the ability to repel solvent molecules, offering new insights into the rational design of advanced battery interfaces.