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.