Thermoelectric oxide NaCo2O4 nanofibers fabricated by electrospinning

For the first time, sodium cobalt oxide (NaCo2O4) nanofibers with diameter of similar to 20-200nm were prepared by electrospinning a precursor mixture of sodium acetate/cobalt acetate/PAN, followed by calcination treatment of the electrospun composite nanofibers. The sodium cobalt oxide nanofibers were characterized by TG-DTA, X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The NaCo2O4 nanotibers calcined at 300 and 400 degrees C were polycrystalline of gamma-NaCo2O4 phase having diameters of similar to 20-60 nm with grain sizes of similar to 5-10 nm, and whereas the nanofibers calcined at 800 degrees C were single crystal having linked particles or crystallites with particle sizes of similar to 60-200 nm. The results indicated a significant effect of calcination temperature on the crystalline phase and morphology of the nanofibers. (c) 2005 Elsevier B.V. All rights reserved.