Abstract Core-shell Fe3O4@Fe ultrafine nanoparticles (nano-Fe3O4@Fe, Fe3O4 content 84 wt%) with a core (Fe) diameter of 5.1 ± 1.4 nm and a shell (Fe3O4) diameter of 10.9 ± 1.6 nm is prepared by a liquid-phase pyrolysis and partial oxidation method. It is found that the core-shell Fe3O4@Fe ultrafine nanostructure can efficiently improve the electrochemical performance of Fe3O4 as anode material for Li-ion batteries in terms of rate capability and cycle life. For instance, specific capacities of 884 and 705 mAh/g can be obtained for the nano-Fe3O4@Fe electrode after 100 cycles at 200 mA/g and 500 cycles at 1000 mA/g, respectively. It is believed that these improvements can be attributed to the significant shortened transfer distance of electrons and Li-ions with relatively low specific surface area, ultrahigh electronic conductivity inside the nanoparticles and good ductility to accommodate the asymmetric volume change.

中文翻译：

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核壳 Fe 3 O 4 @Fe 超细纳米粒子作为锂离子电池的高级阳极

摘要 核（Fe）直径为 5.1±1.4 nm，壳（Fe3O4）直径为 10.9±1.6 nm 的核壳 Fe3O4@Fe 超细纳米粒子（纳米 Fe3O4@Fe，Fe3O4 含量为 84 wt%）液相热解和部分氧化法。结果表明，核壳Fe3O4@Fe超细纳米结构可以有效提高Fe3O4作为锂离子电池负极材料的电化学性能，提高倍率性能和循环寿命。例如，纳米 Fe3O4@Fe 电极在 200 mA/g 下循环 100 次和 1000 mA/g 下循环 500 次后分别获得 884 和 705 mAh/g 的比容量。据信，这些改进可归因于比表面积相对较低的电子和锂离子的转移距离显着缩短，