Enhanced electrochemical performance of template-free carbon-coated iron(II, III) oxide hollow nanofibers as anode material for lithium-ion batteries

Carbon-coated Fe₃O₄ hollow nanofibers (Fe₃O₄/C hNFs) as a lithium ion battery anode material are prepared through electrospinning, annealing, and hydrothermal processing. At a high current density of 1000 mAg^-1, the template-free Fe₃O₄/C hNFs exhibit high 1st- and 150th-cycle specific capacities of ∼963 and 978 mAhg^-1, respectively. Moreover, Fe₃O₄/C hNFs have excellent and stable rate capability, compared to that of the Fe₃O₄ hNFs, and a capacity of 704 mAhg^-1 at a current density of 2000 mAg^-1. Owing to the carbon layer, the Li-ion diffusion coefficient of the Fe₃O₄/C hNFs, 8.10 × 10^-14 cm² s^-1, is 60 times higher than that (1.33 × 10^-15 cm² s^-1) of the Fe₃O₄ hNFs. These results indicate that Fe₃O₄/C hNFs may have important implications for developing high performance anodes for next-generation lithium ion batteries.