The electrical isolation of fractured silicon and unstable solid electrolyte interphase formed on silicon's surface are two major issues preventing commercialization of silicon anodes in next-generation lithium ion batteries. In this work, we wrap silicon nanoparticles with graphene to maintain the electrical connection, meanwhile, isolating Si from the electrolyte to suppress SEI formation on the Si surface. A facile freeze-drying method followed by thermal reduction was used to synthesize the silicon-graphene (Si-G) composites. We found that the Si-NP's can be tightly wrapped by graphene when the composites utilized an optimal starting ratio of 1:2 (Si-NP:GO), attributing to significantly improved cyclic stability and cycle efficiency. Taking the facile fabrication method and the use of commercial Si-NP's into account, Si-G composites could be a promising candidate for the anode material in lithium ion batteries (LIBs). (C) 2014 Elsevier Ltd. All rights reserved.