Nitrogen-doped Mesoporous Carbon-encapsulation Urchin-like Fe3O4 as Anode Materials for High Performance Li-ions Batteries

Nitrogen-doped urchin-like Fe3O4@C composites are successfully fabricated via a facile hydrothermal process and subsequent carbonization. Urchin-like hydroxyferric oxide (alpha-FeOOH) is used as a template and coated by polydopamine (PDA) to form alpha-FeOOH@PDA. Under high temperature and argon atmosphere, urchin-like Fe3O4 with N-doped carbon shell (Fe3O4@C-N) are finally formed. In the electrochemical test, N-doped carbon shell can form stable solid electrolyte interface (SEI) layer, reduce initial capacity loss and improve the reversibility of Fe3O4 for Li ion storage. Compared with naked Fe3O4 nanospheres, Fe3O4@C nanospheres and urchin-like Fe3O4@C composites, the urchin-like Fe3O4@C-N composites display excellent electrochemical performance. The as-prepared Fe3O4@C-N-20-600 shows a reversible specific capacity of 800 mA h g(-1) after 100 cycles at 500 mA g(-1). The significant electrochemical property improvements of urchin-like Fe3O4@C-N composites are attributed to the unique urchin-like structure and the N-doped mesoporous carbon shell. Such a simple and scalable route to construct N-doped carbon encapsulated core-shell structure may be further extended to other high capacity anode and cathode materials. (C) 2016 Elsevier Ltd. All rights reserved.