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Fabrication of core-shells on sheets is considered as an effective strategy to explore novel functional composite materials. Herein, a three-component composite was successfully constructed by dispersing and anchoring carbon-coated Fe3O4 nanoparticle core-shell structures onto reduced graphene oxide (rGO) sheets. Carbonization of glucose polymer formed carbon shells existing between the Fe3O4 particles and rGO sheets. The structure of core-shells placed on rGO sheets formed close connections and high structural stability to the Fe3O4@C-rGO (FCG) composite. Reversible specific capacity up to 884 mA h g−1 at 0.2 C with good recyclability was achieved with FCG as an anode material of lithium-ion batteries. These unique three-dimensional structures of core-shells on sheets are beneficial to enhancing lithium-ion battery storage capacity, cycle stability, and rate performances.Fabrication of novel functional materials is an effective strategy to construct core-shells on sheets. Fe3O4@C-rGO (FCG) composites have been successfully prepared by fabricating carbon shell-coated Fe3O4 nanoparticles (NPs) and reduced graphene oxide (rGO) sheets together. Carbonization of glucose formed carbon shells between Fe3O4 NPs and rGO sheets. The synergism between core-shell structures and sheets contributed to the close connection and high structure stability in FCG. As anode material of lithium-ion batteries (LIBs), the reversible specific capacity of FCG still maintained 748 mA h g−1 after 300 cycles at 0.2 C with good recyclability. This three-dimensional core-shell on sheets structure is beneficial to enhancing lithium storage capacity, cycle stability and rate performance. [ABSTRACT FROM AUTHOR]

Abstract Rational designs of composites of metal compound nanoparticles and carbonaceous matrixes to improve electrochemical kinetics have attracted growing interests in the application as lithium storage anode materials. In this work, novel three dimensional composites of hollow carbonaceous microspheres-reduced graphene oxide with SnO 2 nanoparticles are fabricated by an in situ hybridization method. Benefiting from their particles-hollow sphere-sheets ternary structural characters, these composites revealed excellent electrochemical promoting abilities for Li ion storage. The discharge capacity is up to 944 mA h g–1 after 50 cycles at a current density of 200 mA g–1. After the high-rate charge-discharge cycling at 0.2–2.0 mA g–1, the capacity recovers to 909 mA h g–1 when the current density is reduced back to 200 mA g–1. The carbon matrix with three dimensional structure and appropriate surface by introducing hollow carbonaceous microspheres onto reduced graphene oxide nanosheets as promoter is in favor of excellent ion diffusion channel and high electronic conductivity. The hollow sphere-sheet structures effectively accommodate the huge volume change upon Li ion insertion/extraction. These swimming bladder type composites are promising Li storage anode materials with high capacity and superior rate performance via accelerating kinetics and equilibrium. Graphical abstract Novel three dimensional composites of hollow carbonaceous microspheres-reduced graphene oxide with SnO 2 nanoparticles are fabricated by an in situ hybridization method. Benefiting from their particles-hollow sphere-sheets ternary structural characters, these composites revealed excellent electrochemical promoting abilities for Li ion storage. The discharge capacity is up to 944 mA h g–1 after 50 cycles at a current density of 200 mA g–1. After the high-rate charge-discharge cycling at 0.2–2.0 mA g–1, the capacity recovers to 909 mA h g–1 when the current density is reduced back to 200 mA g–1. These swimming bladder type composites are promising Li storage anode materials with high capacity and superior rate performance via accelerating kinetics and equilibrium. fx1 [ABSTRACT FROM AUTHOR]