Microwave-assisted synthesis of hollow CuO–Cu2O nanosphere/graphene composite as anode for lithium-ion battery

Abstract CuO–Cu 2 O/graphene composite has been successfully prepared by the combination of a microwave-assisted process and subsequent annealing. X-ray diffraction and electron microscopy reveals that copper oxide nanospheres with a size of 120–200 nm are uniformly anchored on graphene nanosheets. The copper oxide nanospheres are composed of numerous CuO and Cu 2 O nanocrystals of ∼10 nm. These nanospheres are hollow and the thickness of the shells is around 50–70 nm. The CuO–Cu 2 O/graphene composite shows a highly reversible capacity and excellent rate performance as anode for Li-ion battery. The reversible capacity of the composite retains 487 mA h g −1 after 60 cycles at 200 mA g −1 . Even when cycled at various rate (200, 500, 1000, 2000, 5000 mA g −1 ) for 60 cycles, the capacity can recover to 520 mA h g −1 at the current of 200 mA g −1 . The enhanced electrochemical performances are ascribed to the hollow spherical architectures, excellent conductivity of graphene sheets, and possible synergistic effects between CuO, Cu 2 O and graphene that enhance the intrinsic properties of each component.