Carbon-coated Si particles binding with few-layered graphene via a liquid exfoliation process as potential anode materials for lithium-ion batteries

In our study, we propose a facile, cost-effective and green process to synthesize few layer graphene (FLG) as a buffer layer to stabilize silicon anode. The as-synthesized FLG framework not only provides electronic-conductive matrix around silicon but also buffers dramatically volume expansion of silicon during charge/discharge processes. In addition, in order to avoid the stripping of Si particles from FLG matrix during long-term cycling process, we further make a dense carbon coating on the surface of Si/FLG to obtain Si/FLG/C composite. Via the dense carbon coating, the electrochemical performance of Si/FLG/C composite could further enhance in terms of rate capability, reversible capacity and cycle life. Electrochemical results demonstrate that Si/FLG/C exhibits better electronic conductivity than that of Si/graphite/C composite. In addition, the resistance of Si/FLG/C electrode was lower than that of Si/graphite/C one by AC impendence analysis. It is believed that the graphene-modified Si/C composite could potentially have opportunities to be promising candidates as anode materials for Li-ion batteries.