▎ 摘　　要

Nanocomposites with ultra-small magnetite (Fe3O4) nanoparticles (similar to 3 nm) uniformly anchored on the surfaces of reduced graphene oxide (RGO) nanosheets were successfully synthesized for anodes in sodium-ion batteries by a novel single-step high-temperature coprecipitation approach. The best electrode delivers a reversible Na+ storage capacity of 204 mA h g(-1) with excellent capacity retention, i.e., 98% of the second-cycle value was retained after 200 cycles.