Effects of VGCF pretreatment on the characteristics of Fe2O3/VGCF composites as anode materials for Li-ion batteries

Two main topics were handled in this study: loss minimization in the irreversible capacity of vapor-grown carbon fibers (VGCFs) by pretreatment techniques and reversible capacity increase in pretreated VGCFs by the deposition of nano-sized Fe₂O₃. VGCFs were ball-milled and acid-treated, and nano-sized Fe₂O₃ particles were supported on the pretreated VGCFs. Their performance as anodes in lithium-ion batteries was characterized using a variety of techniques. Compared to the electrode containing pristine VGCF only, electrodes composed of the pretreated-VGCFs enhanced both charge transfer and discharge capacities due to an increase in lithium-ion mobility. Moreover, the Fe₂O₃ nanoparticles supported on the pretreated VGCFs could eliminate defects and functional groups on the surface of VGCFs generated by the pretreatment, such that the composite of Fe₂O₃ and pretreated VGCF showed higher reversible capacity at any rate of charge/discharge than the composite of Fe₂O₃ and the pristine VGCF. Therefore, the Fe₂O₃/pretreated VGCF composites could be a good candidate for high capacity anodes.