Preparation of alkali metal graphite intercalation compounds in organic solvents

Abstract

Abstract Binary alkali metal graphite intercalation compounds (GICs) and ternary alkali metal organic solvent GICs have been prepared from natural graphite flakes in ether-type solvents containing alkali metals. Here, phenanthrene is used as a dissolving reagent for alkali metals. The stage structures of GICs prepared from five alkali metals; Li, Na, K, Rb and Cs, and four solvents; tetrahydrofuran (THF), 2-methyltetrahydrofuran (MeTHF), 2,5-dimethyltetrahydrofuran (diMeTHF), 1,2-dimethoxyethane (DME) and 1-methoxybutane (MB) are studied by X-ray diffraction. When the THF and DME solvents are used, ternary alkali metal organic solvent GICs are obtained, irrespective of the type of alkali metal. In contrast, binary alkali metal GICs are formed for some limited combinations of alkali metals and organic solvents such as MeTHF. diMeTHF and MB. In the case of MeTHF, the intercalation of Li, Na and K into graphite takes place without the solvent to form binary alkali metal GICs, but Rb intercalates into graphite both with and without the solvent to form ternary and binary GICs, and furthermore only ternary GIC is formed with Cs. In diMeTHF, binary GICs with Li and Cs and ternary GICs with K and Rb are formed. Binary GICs with Li and K are synthesized in MB.