Reduced graphene oxide-Fe_3O_4(rGO—Fe_3O_4) composite has been prepared via a facile and effective hydrothermal method by synthesizing Fe_3O_4 nanospheres on the planes of reduced graphene oxide(rGO).Characterizations suggest the successful attachment of Fe_3O_4 nanospheres to rGO sheets.The rGO—Fe_3O_4composite(66.7 wt%of Fe_3O_4 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-Fe_3O_4 is clearly established by comparison of the results with those from bare Fe_3O_4 nanospheres(capacity declined to 117 mAh g^(-1) only at the 200 th cycle).The excellent electrochemical performance of rGO—Fe_3O_4 composite can be attributed to the fact that the uniform dispersion of the Fe_3O_4 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 Fe_3O_4nanospheres,but also good ionic and electronic transport medium in the electrode.
