Facile Synthesis of Laminated Si@C–Fe3O4 Composite from Exfoliation of Zintl Phase: A Promising Lithium Battery Anode with Superior Rate Capability and Cycling Stability

Two-dimensional (2D) silicon nanomaterial is a promising anode for lithium-ion batteries (LIBs) due to its large specific area, short ion transport path, and minimized volume expansion. However, its batch utilization is greatly limited by complicated synthesis procedures and time or energy consumption. Herein, we report a facile strategy to construct a kind of Si@C–Fe3O4 lamellar composite with enhanced performance as a LIB anode material. The 2D Si nanosheets are thermally exfoliated from the layered Zintl compound CaSi2 reacting with CO2, followed by surface coating of the C–Fe3O4 layer via the decomposition of ferrocene. Throughout 100 cycles, the as-synthesized Si@C–Fe3O4 composite maintains a stable specific capacity of 1000 mA h g–1 at 0.2 A g–1 with a subtle decay. Compared to 2D Si nanosheets, the composite exhibits better specific capacity and rate capability, particularly at high rates. It is found that C–Fe3O4 is an efficient and low-cost component for enhancing the lithium storage capability of Si-based anodes. We expect that this study will provide a simple and scalable path to the practical fabrication of Si-based anodes toward high-performance LIBs.