The effect of flake thickness on the intercalation of graphite

✍ Scribed by J.G. Hooley

• Publisher: Elsevier Science
• Year: 1972
• Tongue: English
• Weight: 593 KB
• Volume: 10
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(72)90038-3

✦ Synopsis

The peripheral expansion of single flakes of natural graphite 0-5 to 3 mm in diameter has been measured during intercalation by solutions of 12 metal chlorides in nitromethane (NM) and by ICI and by H2SO4. As concentration is decreased and thickness is increased the percentage expansion decreases. At 0" 1 M the expansion varies by a factor of 200 from SbCla to WC16 and the amount is not related to the intercalation behavior of the vapor of that metal chloride in graphite. For flakes greater than 10-30/zm thick, the expansion in FeClz solution stops at a certain amount which increases with FeC13 concentration and with flake diameter. It can be started again by first shrinking the flake in NM and then re-exposing it to FeCla solution. Such alternating treatment finally causes a maximum total expansion of 150 per cent. The rate of initial expansion is constant until it abruptly falls to zero in a time which increases with flake thickness and which is greater for flakes of smaller diameter. Gravimetric data show that about 1 mole of NM is intercalated for each mole of FeC13 and that by a cyclic process of exposure to solution and then driving off the NM by heat, a maximum composition of about CTFeCla can be obtained.