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 FeSi2 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.