Yolk-shell Si/SiO_x@Void@C composites as anode materials for lithium-ion batteries

摘要

Silicon (Si) has been considered as one of the most promising anode materials in lithium-ion battery. However, practical applications of Si are hindered by undesirable cycling stability resulting from poor electrical conductivity and huge volumetric change during cycling process. Here, we prepared a yolk-shell silicon/carbon composite by etching carbon-coated heat-treated silicon monoxide (SiO) precursor. The as-prepared Si/SiOx@Void@C composite of inner silicon/silicon oxides and outer carbon shell with voids between them (Si/SiOx @Void @C), shows impressive cycling stability (1020 mAh g(-1) at 1 A g(-1 )over 200 cycles) and excellent rate performance (775 mAh g(-1) at 6 A g(-1) ). The remarkable electrochemical performance is due to the enhanced electrical conductivity originated from the carbon shell and the volume buffer effect of the yolk-shell structure. A combination of the yolk-shell structure with Si/C composites is believed to be a promising way to improve the performance of Si-based materials in lithium-ion batteries.