Polycrystalline tetranary LiNi0.5+delta Mn0.5-delta O2 nanofibers have been successfully fabricated by a sol-gel assisted electrospinning technique. The structures and properties of fabricated nanofibers were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and thermal gravimetric analysis (TGA). After heat treatment of the electrospun fibers at a temperature of 800 degrees C, the LiNi0.5+delta Mn0.5-delta O2 phase was found without other trace phases. Multilayered nanoparticles with a grain size of 50 nm or less within a single fiber are notable from TEM. In this study, it was shown that the sol-gel assisted electrospun LiNi0.5+delta Mn0.5-delta O2 fibers could be formed with the alpha-NaFeO2 type crystal structure at a temperature lower than that in a typical solid-state or sole sol-gel process and possess good thermal stability as high as 800 degrees C. (C) 2008 Elsevier B.V. All rights reserved.