Spindle -shaped core -shell Fe 3 O 4 @N-doped carbon composites scattered in graphene as excellent anode materials for lithium/sodium ion battery

Fe3O4 shows great potential in the energy storage field; however, the low conductivity, particles aggregation and large volume change during the electrochemical process seriously limit its practical application. Here, spindle-shaped core-shell Fe3O4@N-doped carbon scattered in graphene (Fe3O4@NCm/rGO) has been successfully fabricated. SEM and TEM results indicate that the N-doped carbon shell with a thickness of 10 nm was homogenously coating on the spindle-shaped Fe3O4 surface, and at the same time the Fe3O4@NCm particles evenly dispersed on the graphene sheets. Profiting from the N-doped carbon shell and graphene, the Fe3O4@NCm/rGO electrode delivers excellent electrochemical performances both in Li and Na ion half-cells (720 mAh g−1 at 1000 mA g−1 after 500 cycles and 237 mAh g−1 at 1000 mA g−1 after 2500 cycles for Li and Na ion half-cells, respectively). And most importantly, the Fe3O4@NCm/rGO electrode also presents superior lithium and sodium storage performances in Li and Na ion full-cells with 526 mAh g−1 for Li-ion full cell and 192 mAh g−1 for Na-ion full cell. These results demonstrate that the Fe3O4@NCm/rGO composites have great promising applications as anodes in both commercial Li/Na-ion batteries. © 2020 Elsevier B.V.