Abstract: O₄ (rGO-Fe₃O₄) composite has been prepared via a facile and effective hydrothermal method by synthesizing Fe₃O₄ nanospheres on the planes of reduced graphene oxide (rGO). Characterizations suggest the successful attachment of Fe₃O₄ nanospheres to rGO sheets. The rGO-Fe₃O₄ composite (66.7 wt% of Fe₃O₄ in the composite) exhibits a stable capacity of 668 mAh g^-1 without noticeable fading for up to 200 cycles in the voltage range of 0.001-3.0 V, and the superior performance of rGO-Fe₃O₄ is clearly established by comparison of the results with those from bare Fe₃O₄ nanospheres (capacity declined to 117 mAh g^-1 only at the 200th cycle). The excellent electrochemical performance of rGO-Fe₃O₄ composite can be attributed to the fact that the uniform dispersion of the Fe₃O₄ nanospheres growing on the rGO sheets avoids aggregation during Li uptake-release cycling, which is desired for cycle stability. Meanwhile, the rGO sheets afford not only elastic buffer to alleviate the volume variations of Fe₃O₄ nanospheres, but also good ionic and electronic transport medium in the electrode.

Key words: Facile synthetic approach, rGO, FeO nanospheres, Composite, Lithium-ion batteries, High performance