Rational architecture design of yolk/double-shells Si-based anode material with double buffering carbon layers for high performance lithium-ion battery

Abstract

Among the many strategies to fabricate the silicon/carbon composite, yolk/double-shells structure can be regarded as an effective strategy to overcome the intrinsic defects of Si-based anode materials for Li-ion batteries (LIBs). Hereon, a facile and inexpensive technology to prepare silicon/carbon composite with yolk/double-shells structure is proposed, in which the double buffering carbon shells are fabricated. The silicon/carbon nanoparticles with core–shell structure are encapsulated by SiO2 and external carbon layer, and it shows the yolk/double-shells structure via etching the SiO2 sacrificial layer. The multiply shells structure not only significantly improves the electrical conductivity of composite, but also effectively prevents the exposure of Si particles from the electrolyte composition. Meanwhile, the yolk/double-shells structure can provide enough space to accommodate the volume change of the electrode during charge/discharge process and avoid the pulverization of Si particles. Moreover, the as–prepared YDS-Si/C shows excellent performance as anode of LIBs, the reversible capacity is as high as 1066 mA h g−1 at the current density of 0.5 A g−1 after 200 cycles. At the same time, the YDS-Si/C has high capacity retention and good cyclic stability. Therefore, the unique architecture design of yolk/double-shells for Si/C composite provides an instructive exploration for the development of next generation anode materials of LIBs with high electrochemical performances and structural stability.