Atomic scale, amorphous FeOx/carbon nanofiber anodes for Li-ion and Na-ion batteries

Zheng Long Xu, Shanshan Yao, Jiang Cui, Li Min Zhou, Jang Kyo Kim

Research output: Journal article publicationJournal articleAcademic researchpeer-review

78 Citations (Scopus)


The optimal annealing temperature, duration of carbonization and physical constraint from CNFs are identified as the critical parameters that enable the formation of atomic scale, amorphous FeOxparticles. The FeOx/CNF composite electrodes present exceptional cyclic stability for both lithium ion batteries (LIBs) and sodium ion batteries (SIBs) after 500 cycles at 0.5 A g−1: an excellent capacity of 717 mAh g−1with capacity retention (CR) of ~96% for LIBs, and 277 mAh g−1with CR of almost 100% for SIBs. The ultrafine size and amorphous state of FeOxparticles are upheld even after 500 cycles, offering solid evidence for excellent reversibility of the electrodes. Reversible conversion between the amorphous FeOxphase and Fe nanocrystals during charge/discharge reactions are identified as the principal energy storage mechanisms for both batteries. Interestingly, the Fe particles formed after discharge in SIBs are generally larger in size but much smaller in molar amount than in LIBs, which may partly account for the lower specific capacity of SIBs given the same electrode material and the same testing condition. These findings not only enrich our understanding of energy storage behaviors of iron oxide anodes, but also offer a potential strategy to improve the cyclic stability of electrodes made from other transition metal oxides that suffer from large volume changes and poor electrical conductivities.
Original languageEnglish
Pages (from-to)10-19
Number of pages10
JournalEnergy Storage Materials
Publication statusPublished - 1 Jul 2017


  • Carbon nanofiber
  • Electrospinning
  • FeO x
  • Lithium ion battery
  • Sodium ion battery

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • General Materials Science
  • Energy Engineering and Power Technology


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