Ultrafast/stable lithium-storage electrochemical performance of Fe/Fe3O4/carbon nanocomposites as lithium-ion battery anode

Fe/Fe3O4/carbon nanocomposites are synthesized by a facile two-step solvothermal method. Some (Fe3O4, Fe) nanoparticles are embedded in carbon nanosheets, and some other (Fe3O4, Fe) nanoparticles form core-shell structure (Fe3O4/C, Fe/C) on the surface of carbon nanosheets. As anode of lithium-ion battery, the nanocomposites exhibit ultrafast/stable cycling performance. Their charging time can be shortened to merely ~4 min with reversible capacity of 330 mAh/g and maintains 108 mAh/g after 3500 cycles. At 0.2 C rate, the reversible capacity is up to 690 mAh/g and it increases to 755 mAh/g after 100 cycles. The present results demonstrate a right way to produce metal-oxide/carbon nanocomposites in mass production for realizing ultrafast-charging lithium-ion battery.