Laterally Confined Graphene Nanosheets and Graphene/SnO2 Composites as High-Rate Anode Materials for Lithium-Ion Batteries

High-rate anode materials for lithium-ion batteries are desirable for applications that require high power density. We demonstrate the advantageous rate capability of few-layered graphene nanosheets, with widths of 100-200 nm, over micro-scale graphene nanosheets. Possible reasons for the better performance of the former include their smaller size and better conductivity than the latter. Combination of SnO2 nanoparticles with graphene was used to further improve the gravimetric capacities of the electrode at high charge discharge rates. Furthermore, the volumetric capacity of the composites was substantially enhanced compared to pristine graphene due to the higher density of the composites.