Design and Synthesis of Bubble-Nanorod-Structured Fe₂O₃–Carbon Nanofibers as Advanced Anode Material for Li-Ion Batteries

Abstract

A structure denoted as a "bubble-nanorod composite" is synthesized by introducing the Kirkendall effect into the electrospinning method. Bubble-nanorod-structured Fe2O3-C composite nanofibers, which are composed of nanosized hollow Fe2O3 spheres uniformly dispersed in an amorphous carbon matrix, are synthesized as the target material. Post-treatment of the electrospun precursor nanofibers at 500 °C under 10% H2/Ar mixture gas atmosphere produces amorphous FeOx-carbon composite nanofibers. Post-treatment of the FeOx-carbon composite nanofibers at 300 °C under air atmosphere produces the bubble-nanorod-structured Fe2O3-C composite nanofibers. The solid Fe nanocrystals formed by the reduction of FeOx are converted into hollow Fe2O3 nanospheres during the further heating process by the well-known Kirkendall diffusion process. The discharge capacities of the bubble-nanorod-structured Fe2O3-C composite nanofibers and hollow bare Fe2O3 nanofibers for the 300th cycles at a current density of 1.0 A g(-1) are 812 and 285 mA h g(-1), respectively, and their capacity retentions measured from the second cycle are 84 and 24%, respectively. The hollow nanospheres accommodate the volume change that occurs during cycling. The unique structure of the bubble-nanorod-structured Fe2O3-C composite nanofibers results in their superior electrochemical properties by improving the structural stability during long-term cycling.

Fabrication of magnetic nanorods and their applications in medicine

“…Some of the most important of these methods are electrospinning [34], plasmon-enhanced spectroscopy [35], Ultraviolet fluorescence [36], adhesion [37], novel flame-gradient [38], and direct growth on Titanium foil [39], adsorption [40], layer by layer [41] and electron beam [42].…”

NiO hollow microspheres interconnected by carbon nanotubes as an anode for lithium ion batteries

“…To further improve the rate performance of MOs, much effort has been made to accommodate the active materials with porous conductive scaffolds to form the nanocomposites such as carbon nanotubes [11][12][13][14][15][16][17][18][19], graphene [20][21][22][23][24] and carbon nanofibers [25][26][27][28][29] because they could provide long-range conductivity, well controlled interface between MOs and conducting carbons, and more robust network structure. In particular, CNTs is a good candidate for a support matrix in novel anode material for enhanced lithium storage due to its high electrical conductivity, rich porosity and high tensile strength [30,31].…”

Tailoring Iron Oxide Nanostructures for High-Capacity Lithium Storage

“…[33] The α-Fe2O3 ladder-like nanostructure delivered a stable capacity of over 1100 mAh·g -1 at 0.1 C. Even at a high rate of 5C, the sample exhibited a capacity of 645 mAh·g -1 after 1200 cycles. and TEM (c) images of α-Fe2O3 ladder-like nanostructure; [33] TEM images of α-Fe2O3 nanotubes (d); [35] schematic illustration (e) and TEM image (f) of α-Fe2O3-carbon composite nanofibers constructed by α-Fe2O3 nanobubbles dispersed in an amorphous carbon matrix; [41] digital photo of a flexible α-Fe2O3-SWCNT membrane (g), TEM image of α-Fe2O3-SWCNT (h), TEM image of Fe2O3 nanoparticle filled CNT (i). [44] Nanotubes with efficient Li + diffusion channels and sufficient free space for volume expansion have also been demonstrated to be a promising electrode structure.…”