Graphite, intercalation compounds fluorides

A quite different sort of graphite intercalation compound is formed by the halides of many elements, particularly those halides which themselves have layer structures or weak intermolecular binding. The first such compound (1932) was with FeCl3 chlorides, in general, have been the most studied, but fluoride and bromide intercalates are also known. Halides which have been reported to intercalate include the following ... 

Fig. 6. Galvanostatic discharge curves of button-type cells Li/1 M L1CIO4 + EC PC DME/LT—CFV, HT—CF, at 40 mAg 1. LT—CFV fluorine-graphite intercalation compound prepared at a low temperature, HT—CFV graphite fluoride prepared at a high temperature (reproduced with permission from J. Power Sources, 68 (1994) 708 [34]).

Layer misfit was first recognised in the structures of two metal chloride-graphite intercalation compounds. Intercalates of graphite with many other metal halides, including fluorides and bromides, have since been reported, but they seem to be of the CC type and are not discussed here. 

Panich, M. Nuclear magnetic resonance stndy of flnorine-graphite intercalated compounds and graphite fluorides. Svnth. Metals 1999 100 169-185. 

Touhara, H. Suganuma, S. Okino, F., "Lithium Batteries with Fluorine-Graphite Intercalation Compound Cathodes. Post-Graphite Fluoride Cathode," Tanso 1991,150, 328. 

The addition of lithium fluoride, due to its solubility in a fluorine bath, can suppress the occurrence of the anode effect.2 Nakajima and co-workers reported that the carbon/hydrogen fluoride/fluorine system formed the graphite fluoride intercalation compound C4F as a solid... 

Molybdenum(VI) fluoride will insert into graphite to give8,29 nominal C5MoF6 and other compositions, and with fullerene C60 it forms30 an intercalation compound in which some oxidation process has occurred since the molybdenum exists as a molybdenum(V) fluoride species. 

It is believed that the discharge mechanism involves the formation of an intermediate lithium intercalation compound in which both lithium and fluorine are situated between the carbon layers of the graphitic structure. The carbon formed is graphitic and improves the cell performance as the discharge progresses, leading to a high cathode utilization - close to 100% for low currents. The lithium fluoride precipitates. 

After an introductory discussion of such misfit structures, various terms that have previously been applied are reviewed, and degrees of incommensurability are used as the basis for a systematic nomenclature. The known structures of specific examples are then discussed graphite intercalates minerals with brudte-like layers as one component (koenenite, valleriite, tochilinites) silicates heavy metal sulphides (cylindrite, incaite, franckeite, cannizzarite, lengenbachite, lanthanum-chromium sulphide) anion-excess, fluorite-related yttrium oxy-fluorides and related compounds. 

N. Watanabe, H. Touhara, T. Nakajima, T. Mallouk, H. Selig and N. Bartlett, Foreword and Chap. 8, Fluorine Intercalation Compounds of Graphite, Inorganic Solid Fluorides, Chemistry and Physics, ed. P. Hagenmuller, Academic Press, pp. xiii-xiv and Sec. II, Chap. 8 (1985) 331. 

The formation of the non-conducting lamellar intercalation compounds graphite oxide and graphite fluoride - has been the subject of several... 

The electrical conductivity of carbon fibers is improved by intercalating donors (e.g., alkali metals) or acceptors (e.g., Br2, CI2, F2, chlorides or fluorides) between the carbon layers [1] [62]. These intercalation compounds are more easily formed in fibers which exhibit a highly ordered graphitic structure, i.e., the mesopitch based UHM carbon fibers. Some intercalation... 

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