Spontaneous Formation of Conductive Solid Electrolyte Interphase on Porous Si@C@ZIF Anodes for Highly Stable Lithium-Ion Batteries

Nanostructured silicon (Si) is a highly promising anode material for next-generation lithium-ion batteries (LIBs) due to its ultra-high theoretical capacity (Li 22 Si 5 , ∼4200 mAh g − 1 ), yet its practical application is hindered by poor conductivity and drastic volume expansion (300–400%). Here, Si nanoparticles are in situ encapsulated within a ZIF-8 framework, guided by a pre-applied carbon coating, forming a porous core–shell architecture that simultaneously enhances ionic/electronic transport and buffers volumetric changes. The resulting Si@C@ZIF anode delivers a reversible capacity of 1030 mAh g − 1 after 500 cycles at 1.0 A g − 1 . In a full cell with LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), 76.8% capacity retention is maintained at 0.5 C over 260 cycles. Post-cycling analysis reveals a robust solid electrolyte interphase (SEI) enriched in Li 3 N and LiF. Density functional theory (DFT) calculations indicate that preferential LiPF 6 adsorption facilitates conductive SEI formation, accelerating Li + diffusion and enhancing interfacial stability, demonstrating a low-cost route to highly durable Si/C nanocomposite anodes for practical high-energy LIBs.