In situ synthesis of Fe3O4-reinforced carbon fiber composites as anodes in lithium-ion batteries

alpha-Fe2O3 hollow nanofibers with wall thicknesses of 45 +/- 16 nm were fabricated via centrifugal spinning of a solution containing Fe(NO3)(3)center dot 9H(2)O and polyvinylpyrrolidone. These fibers were subjected to mechanical milling and mixed in ethanol. Polyacrylonitrile (PAN) fiber mats were also fabricated by centrifugal spinning from dimethylformamide-based solutions. The as-prepared PAN fibrous mats were dipped in the iron-oxide suspension. The coated PAN membranes were then subjected to a heat treatment which yielded carbon fibers coated with Fe3O4 nanoparticles. Both pure carbon fibers (carbonized PAN fibers) and Fe3O4/C composite fibers were used as anode materials in Li-ion batteries. The Fe3O4/C composite anode exhibited high specific capacity and good cycle stability when compared to that of the carbon-fiber electrode. An initial discharge capacity (Li insertion) of 882 mAh g(-1) was obtained for the Fe3O4/C composite fibers with promising cycle performance and rate capability. These composite fibers show promising applications as electrode materials in high-performance rechargeable lithium-ion batteries.