Nitrogen-doped carbon layer embedded with FeCoNi alloy co-modified silicon-based anode material and its high-performance lithium-ion battery

A core-shell Si@C@FeCoNi anode with dual protective coating is rationally constructed. • Synchronous carbonization and alloying of Si@C@FeCoNi is achieved in one step. • The composite delivers a high initial Coulombic efficiency of 91%. • A high reversible capacity of 859.2 mAh g −1 is retained after 350 cycles at 2 A g −1 . • Synergistic effect of N-doped carbon and FeCoNi alloy ensures superior performance. To address severe volume variation upon charge/discharge cycling and inherent low electronic conductivity of silicon-based anode materials for lithium-ion batteries. A novel silicon‑carbon composite anode denoted Si@C@FeCoNi is rationally constructed, which features a dual protective coating consisting of polydopamine-derived N-doped carbon and FeCoNi ternary alloy nanoparticles. Polydopamine first undergoes self-polymerization on the surface of nanosized silicon and subsequently adsorbs Fe, Co and Ni metal cations. A one-step thermal treatment is then conducted under an Ar/H₂ atmosphere to realize synchronous carbonization and alloying. The as-prepared composite presents a distinct core-shell configuration, with silicon nanoparticles as the inner core and a homogeneous N-doped amorphous carbon as the outer shell. Abundant FeCoNi alloy nanoparticles with a face-centered cubic phase are uniformly embedded throughout the carbon matrix with particle sizes ranging from 5 to 10 nm. The obtained Si@C@FeCoNi composite delivers superior lithium storage performances with a high initial Coulombic efficiency of 91% and a high reversible capacity of 859.2 mAh g −1 after 350 long-term cycles at 2 A g −1 . Meanwhile, outstanding rate capability is realized, delivering a high capacity of 942 mAh g −1 at 5 A g −1 . The full cell paired with commercial NCM622 cathode demonstrates satisfactory cycling durability and application potential. This work offers a facile and effective structural modulation strategy toward advanced high-performance silicon-based anodes via multi-component synergistic engineering. Download: Download high-res image (174KB) Download: Download full-size image