Structural studies of the stage III lithium-graphite intercalation compound

Electrochemical intercalation of unsolvated lithium ions into pyrographite has been carried out in LiClO4-carbonate electrolyte solution. The pure stage III lithium-graphite intercalation compound has been isolated and characterized by X-ray diffraction studies. The oriented texture of pyrographite has allowed the separated study of the different families of Bragg reflections. The identity period along the c-axis. I-c, is equal to 1040.80 pm corresponding to an intercalation distance d(1) equal to 374.80 pm. There is no evidence for a 2D structural organization of the intercalated lithium species. The a and b parameters of the graphite sublattice are equal to 246.84 pin corresponding to an in-plane C-C distance of 142.50 +/- 0.05 pm. Comparison between experimental data and some theoretical models suggests a ABA/ACA stacking of the graphene layers along the c-axis with a parameter c equal to 21(c). However. a contribution of a ABA/ABA stacking with c = I-c is also probable. (C) 2002 Elsevier Science Ltd. All rights reserved.