Structural defects in mechanically ground graphite

Highly ordered synthetic graphite was mechanically ground in a planetary ball mill. The interlayer spacing d(002) was found to increase in the grinding process with the reduction of the crystalline size L-a, L-c. The specific surface area increased to over 600 m(2)/g at the maximum. The result of Raman spectroscopy shows: that the ground graphite yields a smaller value of full width at half maximum (FWHM) of the 1350 cm(-1) peak than the heat-treated carbon for a given value of L-a. This indicates the difference in the type of structural defects involved between the heat-treated carbon and ground graphite. A further suggestion of this result is that the mechanically ground graphite has more uniform boundary and a less-defective structure of hexagonal graphite lattice within the layer planes than heat-treated carbon. (C) 1999 Elsevier Science Ltd. All rights reserved.