Cu-Fe-modified silicon nanowire anode with dual-carbon synergistic confinement for high-performance lithium storage

Silicon is a promising high-capacity anode material for next-generation lithium-ion batteries, yet its severe volume change during cycling remains a major challenge. This work reports a multi-level structural design of a silicon-carbon composite anode through a combined physical vapor deposition and chemical vapor deposition (PVD-CVD) process. The composite consists of expanded graphite (EG) as a conductive and mechanically robust scaffold, in situ grown silicon nanowires (Si NWs ) enabled by Cu-Fe bimetallic additives, and a uniform pyrolytic carbon (C py ) coating. The Cu-Fe system promotes silicon vapor transport and forms conductive silicides (Cu 3 Si and FeSi 2 ), which enhance electrical conductivity and buffer mechanical stress. The resulting EG/CuFe-Si/C electrode exhibits a high initial charge capacity of 1746 mAh g −1 with an initial Coulombic efficiency of 88.72% at 0.2 A g −1 . It also shows remarkable cycling stability, retaining 79.3% of its capacity after 200 cycles, and maintains 876.6 mAh g −1 after 1000 cycles at a high current density of 2 A g −1 . The hierarchical structure effectively accommodates volume expansion, while the integrated conductive network and bimetallic synergy collectively enhance Li + diffusion and electrode integrity. This strategy provides a viable pathway for developing high-performance silicon-based anodes. • A dual-carbon architecture synergistically confines Si nanowires. • Cu-Fe bimetallic system in-situ constructs conductive and buffering silicides. • This multi-level design integrates expansion tolerance with efficient ion/electron conduction.