Sheet-like and fusiform CuO nanostructures grown on graphene by rapid microwave heating for high Li-ion storage capacities

This paper reports CuO-graphene layer-by-layer hybrid nanostructures by a fast microwave irradiation method. The CuO nanosheets or fusiform morphologies were obtained by varying the reaction temperature of microwave heating. These CuO nanostructures were uniformly dispersed on graphene nanosheets (GNS), forming layer-by-layer nanostructures after drying and stacking. CuO nanostructures were designed as the spacer to prevent the reassembly of GNS to graphite sheets so that the unique properties relative to few-layer graphene nanosheets (GNS) could be retained in the practical applications. When evaluated as anode materials for Li-ion batteries, the CuO-GNS composites showed substantially enhanced lithium-storage capacities compared to CuO materials and GNS, which has been attributed to the improvement of structure stability and electrical contact by GNS for a long time upon repetitive cycling.