Flexible free-standing graphene foam supported silicon films as high capacity anodes for lithium ion batteries

Silicon film was deposited onto free-standing graphene foam by chemical vapor deposition. The resultant samples showed high flexibility and were used as anodes for lithium-ion batteries without using any binder and additive. High reversible areal capacity of 1.4 mAh cm−2 was obtained at a current density of 0.22 mA cm−2, which corresponds to a gravimetric capacity as high as 620 mAh g−1 by considering the mass of the whole electrode. The improved electrochemical performance can be attributed to the unique hollow structure of the graphene foam which could provide stable support to the deposited Si film, and accommodate the volume changes to relieve strain-induced cracks of Si during cycling.