Vibrational spectra of superdense lithium graphite intercalation compounds

IR investigations of lithium graphite intercalation compounds with different lithium in-plane density (LiC6, LiC4, LiC2) were carried out. The spectra interpretation was done on the basis of normal coordinate analysis for model structures. LiC2 and LiC4 spectra exhibit the bands corresponding to a complex skeleton stretching in Li-7 or LiC6 clusters including equilateral triangles of metal atoms at short distances which shows that covalence exists between Li atoms in the intercalated layer and that LiCx decomposition proceeds keeping these clusters in LiCx structure for x < 4 at least. (C) 1998 Elsevier Science Ltd. All rights reserved.