Nano-Fe3C in-situ embedded into porous carbon wrapped nano-Si composite towards stable high-performance lithium-ion battery anode

Large volume expansion during charge/discharge process, as well as low electrical conductivity, pose significant challenges for high capacity Si anode in lithium-ion batteries (LIBs). Herein, this work demonstrates a simple but efficient solution to the above problems faced by the Si anode, wrapping Si nanoparticles (NPs) with a well-designed high graphitized porous carbon (PC) while strengthening the Si NPs/PC composite by in-situ introduction of conductive and catalytic Fe3C NPs (namely, construction of a novel Si@Fe3C@PC composite). The effect of the PC and Fe3C NPs on electrochemical kinetics and structural stability of the Si@Fe3C@PC is studied by systematic material and electrochemical characterizations and comparison of the electrochemical properties of Si@Fe3C@PC and control samples. The findings confirm that the combined action of PC and Fe3C NPs not only enhances electrical conductivity and structural stability but also improves Li+ diffusion coefficient, solid electrolyte interphase (SEI) stability and capacitive contribution ratio of the Si@Fe3C@PC anode. As a result, the Si@Fe3C@PC exhibits excellent performance as LIB anodes such as high capacity (1320.1 mA h g−1 after 380 cycles at 100 mA g−1), superior rate capability (1241.4 mA h g−1 after 10 cycles at 3000 mA g−1) and long lifespan (680.0 mA h g−1 after 1500 cycles at 3000 mA g−1), demonstrating the significant boosting effect of this strategy for improving Si-based anode performance.