Uniformly modified iron nanoclusters synergistically enhance Interface stability and electrochemical performance of silicon anodes.

Silicon nanoparticles (Si NPs) are regarded as one of the most promising anode materials for lithium-ion batteries (LIBs) owing to their exceptionally high theoretical capacity. Nevertheless, their practical application is severely restricted by intrinsically low electrical conductivity and pronounced volume expansion during lithiation and delithiation. Here, we report the construction of a homogeneous Fe/C composite coating on silicon particles via a facile surface deposition approach, enabling the simultaneous modulation of both bulk-phase structural stability and the chemical composition of the solid electrolyte interphase (SEI). Structural characterization reveals that the continuous carbon layer functions as a highly conductive network, establishing efficient electron transport pathways, while also acting as a physical confinement barrier that suppresses detrimental electrode-electrolyte interfacial reactions. Concurrently, uniformly dispersed Fe nanoclusters catalytically regulate SEI formation kinetics, inducing the preferential decomposition of LiPF6 to generate a compact, inorganic-rich interfacial layer. This tailored SEI enhances lithium-ion conductivity while preserving its electronic insulation, thus achieving concurrent optimization of ionic and electronic transport properties. When paired with a LiNi0.8Mn0.1Co0.1O2 cathode in a full-cell configuration, the Fe/C-Si anode delivers a discharge capacity of 152.67 mAh g-1 with 86.34% capacity retention after 200 cycles. This Fe/C composite coating strategy provides a robust and effective route for stabilizing both the bulk structure and the interfacial chemistry of high-strain anode materials, offering new insights into the design of next-generation high-performance LIBs.