Graphene-encapsulated SnO2 hollow spheres as high-performance anode materials for lithium ion batteries

Graphene-encapsulated SnO2 hollow spheres (GE-SnO2 HS) are synthesized by a simple electrostatic self-assembly process. The prepared composite consists of SnO2 hollow spheres (SnO2 HS) in the interior, which are encapsulated by flexible ultra-thin graphene shells at the exterior. This novel architecture is expected to buffer large volume changes and effectively prevent the detachment and agglomeration of SnO2 during the lithiation and delithiation processes. The GE-SnO2 HS composite exhibits much better electrochemical performance than bare SnO2 HS. In addition, the composite delivers a high reversible capacity of 422 mA h g−1 after 100 cycles at a current density of 158 mA g−1 and a capacity of 237 mA h g−1 after 30 cycles at a higher current density of 1580 mA g−1. These results suggest that the GE-SnO2 HS composite can provide new opportunities to enhance the properties of tin-based materials for use in high-capacity lithium ion batteries.