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

Abstract

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.