Regulating interfacial adsorption via hierarchical dual-coating for homogeneous LiF-rich SEI and long-cycling Si/C anodes

High-capacity silicon/carbon composite anodes for lithium-ion batteries face rapid capacity degradation from extreme volume changes due to conventional organic-dominated solid electrolyte interphase (SEI) lacking mechanical/ionic stability. Constructing robust inorganic SEI (e.g., LiF-dominated interphases) requires synergistic control of electrolyte interactions at the inner Helmholtz plane (IHP) and stress-adaptive interfacial architectures. Herein, a hierarchical dual-coating strategy integrating polyaniline (PANi) and laser-induced graphene (LIG) on SiO x anodes addresses this challenge. PANi layer selectively enriches fluorinated ethylene carbonate (FEC) at the IHP via dipole-dipole interaction, enabling preferential FEC reduction at 1.3 V (vs. Li/Li + ) to form LiF-dominated SEI. Theoretical calculations confirm higher FEC adsorption density and stronger adsorption energy on the hierarchically dual-coated SiO x /LIG/PANi-2 (−0.33 eV) versus bare SiO x (−0.09 eV). Meanwhile, LIGʼs 3D porous conductive scaffold dissipates stress, sustaining structural integrity under repeated expansion. The optimized SiO x /LIG/PANi-2 anode achieves 1812.5 mAh g −1 initial capacity with 90.5 % initial Coulombic efficiency at 0.1 A g −1 and retains 87.7 % capacity after 1000 cycles at 2.0 A g −1 , demonstrating exceptional electrochemical stability. Post-cycling analyses further validate the homogeneity of LiF-rich SEI, robust mechanical resilience, and exceptional electrode integrity. This atomic-scale IHP regulation, harmonized with macro-scale stress engineering, offers scalable strategies for silicon anodes in high-energy-density batteries.