Structure of fluorine-graphite intercalation compounds synthesized in gaseous and anhydrous liquid hydrogen fluoride with fluorine gas
✍ Scribed by K. Amine; T. Nakajima; M. Motoyama
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 449 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0008-6223
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✦ Synopsis
The fluorination of highly oriented pyrolytic graphite (HOPG), powdery and flaky natural graphites, and carbon fiber (P 100) has been performed in a fluorine atmosphere with HF gas (5.3 x 103-4.8 x lo4 Pa), or by flowing fluorine gas in anhydrous liquid hydrogen fluoride (AHF) at ambient temperature. The obtained C,Fs were the stage 1 to 2 compounds with composition of C,,,F to C,,,F. The stage 1 phases prepared from HOPG and pyrolytic graphite have shown large I, values of 1.12 nm to 1.18 nm. This result has coincided with the model that the stage 1 phase with large I, values is a bi-intercalation phase in which two kinds of almost ionically and semi-covalently bonded fluorine atoms with different C-F bond lengths are inserted in every other carbon layer. However, stage 1 C,F samples prepared from natural graphite powder and carbon fiber showed only one strong (001) diffraction line in most cases. X-ray powder diffraction and electron diffraction have revealed the absence of an in-plane superlattice at all stages.