Synthesis and Characterization of Silicon/Reduced Graphene Oxide Composites as Anodes for Lithium Secondary Batteries.

Silicon (Si) is one of the most attractive anode materials for lithium secondary batteries because of its large theoretical capacity, high safety, low cost and environmental benignity. However, Si-based anode material needs to overcome the structural change of the solid-electrolyte interphase due to the large volume change during cycling. To resolve these problems of composites by exploiting the superior conductivity, large specific surface area and flexibility of graphene, we have synthesized reduced graphene oxide (rGO)/Si composite electrode via a simple dip-coating method. Nickel foam is used as a current collector and template for the electrode fabrication. At 0.03 wt%, Si concentration, the rGO/Si composite anode presented the excellent cycle performance with large reversible capacity (778 mAh g-1 after 100 cycles). The characteristics of the rGO/Si composites were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Raman and X-ray photoelectron spectroscopy (XPS). The improved anode performance of the rGO/Si composite anode is ascribed to the rGO serving as a buffer layer, thereby preventing the volume expansion of Si nanoparticles, and provide facile electron pathways.