Strongly coupled N-doped carbon/Fe3O4/N-doped carbon hierarchical micro/nanostructures for enhanced lithium storage performance

A strong interface coupling is of vital importance to develop metal oxide/carbon nanocomposite anodes for next-generation lithium ion batteries. Herein, a rational N-doped carbon riveting strategy is designed to boost the lithium storage performance of Fe3O4/N-doped carbon tubular structures. Polypyr-role (PPy) has been used as the precursor for N-doped carbon. N-doped carbon-riveted Fe3O4/N-doped carbon (N-C@Fe3O4@N-C) nanocomposites were obtained by pyrolysis of PPy-coated FeOOH@PPy nanotubes in Ar atmosphere. When tested as an anode for LIBs, the N-C@Fe3O4@N-C displays a high reversible discharge capacity of 675.8 mA h g(-1) after 100 cycles at a current density of 100 mA g(-1) and very good rate capability (470 mA h g(-1) at 2 A g(-1)), which significantly surpasses the performance of Fe3O4@N-C. TEM analysis reveals that after battery cycling the FeOx particles detached from the carbon fibers for Fe3O4@N-C, while for N-C@Fe3O4@N-C the FeO(x )particles were still trapped in the carbon matrix, thus preserving good electrical contact. Consequently, the superior performance of N-C@Fe3O4@N-C is attributed to the synergistic effect between Fe3O4 and N-doped carbon combined with the unique structure properties of the nanocomposites. The strategy reported in this work is expected to be applicable for designing other electrode materials for LIBs. (C) 2018 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.