Core–shell Fe@Fe3C/C nanocomposites as anode materials for Li ion batteries

Core–shell Fe@Fe3C/C nanocomposites were prepared by adopting α-FeOOH nanorods as the Fe precursor though a simple and green route. The obtained core–shell nanospheres consisted of single crystalline Fe cores (20–50 nm) coated with well-proportioned Fe3C shell (∼8 nm) in amorphous carbon. The composites delivered a reversible capacity of ∼500 mAh g−1 after 30 cycles. However, no obvious changes were observed in the XRD patterns of Fe@Fe3C/C electrodes before and after the discharge process, indicating that Fe and Fe3C are inactive for lithium storage. Many characterizations were performed to propose a reasonable explanation about the Li storage capacity.

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► Core–shell Fe@Fe3C/C nanocomposites were prepared though a facile and green route.
► Fe@Fe3C cores do not directly react with Li+; however, the composites exhibited higher capacity than that of the carbon component.
► The extra capacity is proposed to the reversible formation/dissolution of some SEI components catalyzed by Fe3C.