Maghemite nanoparticles on electrospun CNFs template as prospective lithium-ion battery anode

Abstract

In this work, maghemite (γ-Fe2O3) nanoparticles were uniformly coated on carbon nanofibers (CNFs) by a hybrid synthesis procedure combining an electrospinning technique and hydrothermal method. Polyacrylonitrile nanofibers fabricated by the electrospinning technique serve as a robust support for iron oxide precursors during the hydrothermal process and successfully limit the aggregation of nanoparticles at the following carbonization step. The best materials were optimized under a carbonization condition of 600 C for 12 h. X-ray diffraction and electron microscopy studies confirm the formation of a maghemite structure standing on the surface of CNFs. The average size of γ-Fe2O3 nanoparticles is below 100 nm, whereas CNFs are ∼150 nm in diameter. In comparison with aggregated bare iron oxide nanoparticles, the as-prepared carbon-maghemite nanofibers exhibit a higher surface area and greatly improved electrochemical performance (>830 mAh g-1 at 50 mA g-1 for 40 cycles and high rate capacity up to 5 A g-1 in the voltage range of 0.005-3 V vs Li). The greatly enhanced electrochemical performance is attributed to the unique one-dimensional nanostructure and the limited aggregation of nanoparticles. © 2014 American Chemical Society.