Hollow carbonaceous microspheres-reduced graphene oxide enhances lithium storage performance of SnO2-based anode

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 SnO₂ 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.