Silicon/graphene/carbon hierarchical structure nanofibers for high performance lithium ion batteries

Silicon/graphene/carbon composite nanofibers (Si@RGO@C NFs) with a hierarchical structure are prepared by encapsulating graphene coated Si nanoparticles in the interconnected carbon nanofibers based on an electrospinning technology. For the hierarchical structure, Si nanoparticles are embedded in the graphene and the core-shell structure formed, which is further wrapped by the carbon nanofibers. As lithium ion battery anode, the well-defined Si@RGO@C NFs demonstrates a reversible capacity of 1228 mAh g−1 and a capacity retention of 72% after 100 cycles with a current density of 800 mA g−1. With the current density gradually increasing to 4000 mA g−1, the electrode displays a specific capacity of 954 mAh g−1, exhibiting superior rate capability compared to the Si nanoparticles. These excellent electrochemical properties are attributed to the hierarchical core shell structure and cross linked network for Si@RGO@C NFs.