Constructing three-dimensional N-doped carbon coating silicon/iron silicide nanoparticles cross-linked by carbon...

Silicon (Si), have been considered as promising anode material for lithium-ion batteries (LIBs), due to its high theoretical specific capacity of 4200 mAh g^-1. However, the poor electrical conductivity and large volume change during lithiation/delithiation process, resulting in poor cycling stability, and seriously hindered the practical application in LIBs. Herein, a multiple Si/Fe_xSi_y@NC/CNTs composite is synthesized and investigated as advanced anode materials for LIBs via a simple one-step method. Such multiple Si/Fe_xSi_y@NC/CNTs composite has several merits including the Fe_xSi_y can not only accommodate the huge volume change of Si nanoparticles, but also enhance the conductivity upon discharge/charge process. Furthermore, the in-situ growth CNTs may help establish a long-range conductivity, and the Nitrogen-doped carbon (NC) layer can further improve the conductivity of Si, as well as inhibit the direct contract between electrolyte and Si during cycling process. Accordingly, the Si/Fe_xSi_y@NC/CNTs-1 exhibits excellent cycling stability (a high capacity of 994.4 mAh g^-1 is maintained at 1.0 A g^-1 after 600cycles) and outstanding rate capability (a suitable capacity of 441.7 mAh g^-1 was obtained even at 5.0 A g^-1). Moreover, the assembled full cell can achieve a capacity of 141.4 mAh g^-1 after 65 cycles at 1.0C, exhibiting outstanding cycling stability. This work provides a prospective way for the commercial production of high-performance Si-based anode materials for LIBs.