An acceptor-type graphite intercalation compound (GIC) of fluoroaluminate, CxAlF4 with a high stage structure (partially intercalated) is expected to be formed according to thermodynamic evaluation of oxidizing power of the combined reactant AlF3 and F2. However, in contrast to the other GICs intercalated by fluorometallates [1], the GIC of fluoroaluminate has not been successfully synthesized, giving graphite fluoride CxF with trace of AlF3 [2]. In the present study, several attempts have been made including electrochemical oxidation of graphite in the electrolyte containing AlF4- [3], the reaction with AlF3 with a high surface area (hs-AlF3) prepared by fluorolysis method [4], and ion exchange of graphite chloroaluminate, CxAlCl4 by the reaction with HF [5]. As a result, a high stage salt solvated with the electrolyte solvent nitromethane was prepared by the electrochemical method. X-ray diffraction pattern was indexed as a third stage GIC with a repeating distance of 1.465 nm. The reaction of graphite with hs-AlF3 and elemental fluorine gave graphite fluoride CxF due to the hydrogen source contaminated in the process. Ion exchange of CxAlCl4 by HF exhibited unexpected decomposition of the compound giving graphene sheets by extreme exfoliation accompanied by the evolution of HCl and CF4.References[1] R. Hagiwara, N. Bartlett, Fluorine-Carbon and Fluoride- Carbon Materials, T. Nakajima ed., Marcel Dekker, Inc., 1995, pp. 67.[2] T. Nakajima, M. Kawaguchi, N. Watanabe, Z. Naturforsch B, 36 , 1419 (1981).[3] K. Matsumoto, K. Takagi, R. Hagiwara, J. Electrochem. Soc. 159, H876 (2012) .[4] S. Ruediger, G. Eltanany, U. Gross, E. Kemnitz, J. Sol-Gel Sci. Tech., 41, 299 (2007).[5] K. Matsumoto, D. Minori, K. Takagi, R. Hagiwara, Carbon, 67, 434 (2014).

Intercalation of discrete AlF<sub>4</sub> anion into graphite

248th National Meeting (2014)

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Intercalation of discrete AlF4 anion into graphite

Intercalation of discrete AlF₄ anion into graphite