Scalable fabrication of nano/porous Fe-Si coated by 2D carbon nanosheets composite anode for high-performance lithium-ion batteries

Undoubtedly, nanosized active materials, rational porous structures, and carbon layer coatings have been proven to be the most effective solutions to address the issues of silicon-based anode materials. Herein, nano/porous Fe-Si coated with carbon nanosheets composite (PFe-Si@NCNS electrode) is synthesized originally from low-cost ferrosilicon by simple ball milling, partial etching, and carbon layer coating. In this material, the introduction of multilayer 2D carbon nanosheets can provide a reliable conductive network, accelerate lithium-ion transport, and retain the mechanical integrity of the active material structure. Additionally, the partially retained FeSi ₂ conductive phase can ensure fast transport of electrons and alleviate the volume expansion effect of silicon (as a buffer medium). As a result, the PFe-Si@NCNS electrode demonstrates a reversible capacity of 991.9 mAh g ^-1, a corresponding capacity retention rate of 92.07% at 0.5 A g ⁻¹ after 100 cycles (vs. 4th cycle; reversible capacity of 731.7 mAh g ⁻¹ after 300 cycles) and a good rate capability of 490.8 mAh g ⁻¹ at 5.0 A g ⁻¹. We expect that industrial ferrosilicon alloys as lithium storage materials provide a new idea by using a simple, convenient and scalable method to prepare silicon-based anode materials for high-performance lithium-ion batteries.