Synthesis of self-assembled hollow-sphere ZnO/rGO nanocomposite as anode materials for lithium-ion batteries

We investigate the lithium storage properties of two kinds of materials as anode for LIB: graphene oxide (GO) and self-assembled hollow-sphere zinc oxide/reduced graphene oxide (ZnO/rGO) nanocomposite. GO is obtained by Hummers method controlled by the various process parameters. The ZnO/rGO hollow sphere nanocomposite is synthesized by a low temperature (95 °C) chemical solution reaction. For ZnO/rGO composite, the capacity is increased remarkably as compared to GO sheets, and this is due to the synergistic effects of both the components in the composite. The GO acts as a conductive buffer layer that promotes the conductivity, and suppresses the volume expansion of ZnO during the charge/discharge process. ZnO/rGO hollow sphere structure nanocomposite has higher capacity 605.36 mAh g ^-1 , which is 4.5 times higher than GO (133.82 mAh g ^-1 ), after 20 cycles. The capacity variation with the charge-discharge rate of ZnO/rGO nanocomposite showed a higher capacity (299.95 mAhg ^-1 at 1700 mAg ^-1 ) than GO (20.09 mAhg ^-1 at 1488 mAg ^-1 ) after 32 cycles.