Abstract:

Three-dimensional graphene nanospheres were prepared by direct-current arc discharge method. The microstructure and morphology of the graphene nanospheres were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), Raman spectrum and X-ray diffraction (XRD) pattern. The electrochemical properties of the three-dimensional graphene nanospheres as the anode materials of lithium ion battery were studied by alternating current impedance and constant current charge-discharge cycle performance. The results show that, at current density of 0.05 A/g, the graphene nanospheres as the anode materials have a high first discharge capacity of 485.9 mAh/g, which is better than has the carbon black (401 mAh/g). When the current density increases to 1 A/g, the three-dimensional nanospheres can still achieve a capacity of 185.4 mAh/g. The three-dimensional nanospheres have little capacity decay after 100 cycles at current density of 0.5 A/g and 2.5 A/g. The results show that the three-dimensional graphene nanospheres have a higher capacity than carbon black as the anode for lithium ion battery, and they have excellent cycling stability, too.

Key words: three dimensional graphene, nanosphere, lithium ion battery