Metal–Organic Framework-Derived Si@FCN Composite Based on Waste Silicon for High-Performance Lithium Storage

Nanosizing cheap kerf loss silicon (KL Si) and then compositing it with carbon is one of the effective ways to address the high-cost and low-cycling-life issues of a silicon-based anode for lithium-ion batteries (LIBs). In this work, a unique ZIFs-derived N-doped silicon–carbon structure (Si@FCN) has been prepared by exploiting the modulating effect of Pluronic F127 on metal–organic frameworks (MOFs). When tested as an anode for a CR3032 half-cell, Si@FCN demonstrates an initial Coulombic efficiency (ICE) of 75.4% at 0.1 A g^–1, highlighting a stable cycling performance with discharge capacity maintained at 842.6 mAh g^–1 (0.1 A g^–1 for 200 cycles), 549.3 mAh g^–1 (0.5 A g^–1 for 300 cycles), and 485.7 mAh g^–1 (1.0 A g^–1 for 300 cycles). It also reveals good rate performance in the range of 0.2–5.0 A g^–1. Such a remarkable electrochemical performance originates from the high surface area and porosity of the composite. The N-doped carbon layer derived from ZIF-8 demonstrated multifunctional enhancements in the electrode. Primarily, it significantly improves electrical conductivity through continuous electron transport pathways. Simultaneously, the mechanically robust carbon matrix effectively accommodates silicon’s substantial volumetric fluctuations during lithiation/delithiation cycles, thereby maintaining structural integrity. Furthermore, the introduced nitrogen heteroatoms create abundant redox sites, which substantially reduce the charge transfer resistance and accelerate redox reaction kinetics. The synthetic strategy for the silicon–carbon composite anode demonstrates enhanced lithium-ion storage capabilities, suggesting strong viability for scalable implementation in next-generation LIBs.