Carbon-coated silicon/crumpled graphene composite as anode material for lithium-ion batteries.

Silicon is a promising anode material for high-capacity Li-ion batteries (LIBs). However, its insulating property and large volume change during the lithiation/delithiation process result in poor cycling stability and in pulverization of Si. In this work, glucose-derived carbon-coated Si nanoparticles (C–Si NPs) are in conjunction with crumpled graphene (cGr) particles by a spray-drying method to prepare a novel composite (C–Si/cGr) material. The prepared C–Si NPs are uniformly embedded in the ridges of the cGr particles. The carbon layer of C–Si can make a good contact with the graphene sheet, resulting in enhanced electrical conductivity and fast charge transfer. In addition, the unique crumpled structure of the cGr can buffer the large volume change upon cycling process and facilitate the diffusion of electrolyte into the composite material. When employed as an anode electrode of LIBs, the C–Si/cGr composites deliver enhanced electrochemical performance, including stable cycling with a discharge capacity of 790 mAh·g−1 after 100 cycles and a rate capability of 654 mAh·g−1 at 2C. The synergistic effect of the carbon layer coating of Si NPs and the crumpled structure of the cGr particles results in a composite with improved the electrochemical performance, which is likely related to its high electrical conductivity and good mechanical stability of composite material. • Novel composite (C–Si/cGr) of carbon-coated Si nanoparticles and crumpled graphene was successfully prepared. • The prepared carbon-coated Si NPs are uniformly embedded in the ridges of crumpled graphene particles. • The unique morphology of the C–Si/cGr composite can buffer the large volume change of Si upon cycling process. • The C–Si/cGr composite delivers enhanced electrochemical performance, including stable cycling and a rate capability. [ABSTRACT FROM AUTHOR]