Preparation of ternary hierarchical silicon/reduced graphene oxide/carbon composites as anodes for lithium–ion batteries

Silicon/reduced graphene oxide/carbon (Si/rGO/C) composite material prepared with a carboxyl methyl cellulose and styrene butadiene rubber (CMC + SBR) hybrid binder is successfully synthesized, characterized, and evaluated as a composite anode for lithium–ion batteries (LIBs). The porous Si/rGO/C composite microspheres with interior meso–pores are obtained by encapsulating Si–based nanoparticles into the rGO/C dual–carbon matrix via self–assembling, ball milling, polystyrene sphere (PSS) template–assisting, and spray drying techniques, which facilitate a fast electron and Li+ ion transport, and mitigate Si pulverization. Compared with bare copper (Cu) foil, as–prepared Si/rGO/C composite electrode based on a carbon–coated Cu (C–Cu) foil assembled with a polyethylene (PE) separator exhibits better rate capability, in particular, at high rates, and a capacity increases to ca. 6–10%. By cycling at 400 mA g−1 for 500 cycles, the Si/rGO/C/C–Cu composite electrode with a capacity retention (CR%) of ∼75% and Coulombic efficiency (CE%) of ∼99.7% retains a higher specific capacity of ∼602 mAh g−1 than that on bare Cu foil (∼314 mAh g−1), which is comparable to those reported in the literature. The synergistic effect of the hierarchical composite anode material together with highly adhesive and electrolyte−hydrophilic C–Cu foil results in much better electrochemical performance as a promising LIB anode. [Display omitted] •Si/rGO/C composite with a CMC + SBR hybrid binder is synthesized as a LIB anode.•The microspheres with interior meso–pores facilitate fast e– and Li+ transports.•The Si/rGO/C composite coated on C–Cu foil exhibits a better C–rate capability.•The Si/rGO/C/C–Cu electrode retains a CR% of ∼75% at 400 mA g−1 for 500 cycles.