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

摘要

Si/graphene nanocomposites have been successfully synthesized by the in-situ growth and magnesiumthermal reduction method. The composition and structure of the composite were characterized by theX-ray diffraction (XRD), Raman spectrum, X-ray photoelectron spectroscopy (XPS) and transmissionelectron microscopy (TEM), respectively. Electrochemical properties were evaluated in two-electrodecells versus metallic lithium. Results showed that Si nanoparticles, c.a. 10 nm in diameter, uniformlydistributed 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-1 -1 -1 -1 more than 592 mAh g after 500 cycles at the current density of 2 A g , and 429 mAh g at 8 A g .-1 Even after 80 cycles at various rates from 0.5 to 8 A g , it still maintained the specific capacity of 892-1 -1 mAh g at 0.5 A g . The excellent cycle performance and rate capability ensured that it might beapplied to the high-power lithium-ion batteries as a flexible, high capability and conductivity anode.