Evidence for glide and rotation defects observed in well-ordered graphite fibers

Abstract

New structural features observed in heat-treated vapor-grown carbon fibers (VGCF's), produced by the thermal decomposition of hydrocarbon vapor, are reported using image analysis of the lattice plane structure observed by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The TEM lattice image of well-ordered graphite fibers (heat-treated VGCF's at 2800 °C) was treated by a two-dimensional fast Fourier transform, showing sharp bright spots associated with the 002 and 100 lattice planes. The heat-treated VGCF's consist of a polygonally shaped shell, and the long and short fringe structures in the TEM lattice image reflect the 002 and 100 lattice planes, respectively. From this analysis, new facts about the lattice structure are obtained visually and quantitatively. The 002 lattice planes remain and are highly parallel to each other along the fiber axis, maintaining a uniform interlayer spacing of 3.36 A. The 100 lattice planes are observed to make several inclined angles with the 002 lattice planes relative to the plane normals, caused by the gliding of adjacent graphene layers. This work visually demonstrates coexistence of the graphitic stacking, as well as the gliding of the adjacent graphene layers, with a gliding angle of about 3-20°. These glide planes are one of the dominant stacking defects in heat-treated VGCF's. On the other hand, turbostratic structural evidence was suggested by AFM observations. The structural model of coexisting graphitic, glide, and turbostratic structures is proposed as a transitional stage to perfect three-dimensional stacking in the graphitization process. These structural features could also occur in common carbons and in carbon nanotubes.

Concentric carbon structures

“…4 the atom superposition, coincident with Moiré patterns detected in micron-size fibers. 12 For testing the validity of this structure we synthesized carbon nanotubes in an arc reactor chamber 13 using known procedures. 2 Special precautions-attained with heat shielding of the arc zone-were taken into account for the extraction of well-annealed samples.…”

Structural analysis of carbon nanofiber by transmission electron microscopy and image processing

“…2) Power spectrum was obtained from the lattice images by means of 2-dimentional fast Fourier transform (2D-FFT) [7]. 3) In order to verify the lattice structure, the real space images were reconstructed by 2-dimentional inverse fast Fourier transform (2D-IFFT), by using the selected area of the 2D-FFT data in correspondence to the speci®c frequencies [8,9]. 4) Power spectrum features were analyzed quantitatively by using the graph of the relation between spacing and peak intensity, which is obtained by means of integration of the power spectrum around its central point.…”

Carbonaceous Anode Materials

“…9 b-II) or linear ( Fig. 16b-III) images, indicating a turbostratic stacking [38]. Thus, the substitution of B atoms in the hexagonal network affects the stacking nature of the host material presumably because of the lattice defects and strain associated with the B substitution.…”