Microwave-assisted synthesis of a Co3O4–graphene sheet-on-sheet nanocomposite as a superior anode material for Li-ion batteries

This paper reports the microwave-assisted synthesis of a Co3O4–graphene sheet-on-sheet nanostructure. This sheet-on-sheet nanocomposite showed an excellent high rate capability and highly reversible large capacity at common rate. A capacity of 931 mA h g−1 was observed at a large current rate of 5C (4450 mA g−1), which was still larger than the theoretical capacity of Co3O4 (890 mAh g−1). The substantially improved electrochemical properties were ascribed to the unique sheet-on-sheet nanostructure. Co3O4 nanosheets were tightly stacked with graphene nanosheets (GNS), therefore volume changes of Co3O4 materials were accommodated in the presence of GNS. On the other hand, sheet-like Co3O4 was very effective to prevent the reassembly of GNS to graphite platelets, thus preserving GNS advantages during repetitive cycling.