Ternary intercalation compounds of carbon materials having a low graphitization degree with alkali metals Original Research Article

The formation of ternary intercalation compounds of carbon materials having a relatively low degree of graphitization (P1) in two different ethers (DME and THF) with alkali metals (Li, Na and K) has been investigated by X-ray diffraction measurement, and the effect of the structure of host for intercalation is discussed. In a 1,2-dimethoxyethane (DME) solution of alkali metals, ternary intercalation compounds with stage-1 structure were obtained from all host carbons, which cover almost the whole range of crystallinity. In tetrahydrofuran(THF), on the other hand, two host effects were found: (1) any intercalation of Li-THF complexes was not observed on the hosts with a P1-value of less than 0.05, and (2) with Na, so-called random stage structure was obtained from the cokes with a P1-value of less than 0.2, though the oriented pyrolytic carbons with similar values of P1 gave stage-1 structure. The crystallinity, which was evaluated from half maximum width of the diffraction line, of these ternary compounds formed in DME and THF solutions was found to be governed by that of pristine hosts.