High Reversible Silicon/Graphene Nanocomposite Anode for Lithium-Ion Batteries

Abstract

Si/graphene nanocomposites have been successfully synthesized by the in-situ growth and magnesium thermal reduction method. The composition and structure of the composite were characterized by the X-ray diffraction (XRD), Raman spectrum, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM), respectively. Electrochemical properties were evaluated in two-electrode cells versus metallic lithium. Results showed that Si nanoparticles, c.a. 10 nm in diameter, uniformly distributed within the graphene matrix forming a perfect conducting network. Galvanostatic charge- discharge cycling of the Si/graphene composite anode exhibited a reversible discharge capacity of more than 592 mAh g-1 after 500 cycles at the current density of 2 A g-1, and 429 mAh g-1 at 8 A g-1. Even after 80 cycles at various rates from 0.5 to 8 A g-1, it still maintained the specific capacity of 892 mAh g-1 at 0.5 A g-1. The excellent cycle performance and rate capability ensured that it might be applied to the high-power lithium-ion batteries as a flexible, high capability and conductivity anode.