Co-intercalation into graphite of lithium and sodium with an alkaline earth metal

After a short overview on the co-intercalation into graphite of light alkali metals-lithium and sodium-with a third element, novel results concerning the co-intercalation of these alkali metals with an alkaline earth metal are given. The intercalation into graphite of lithium together with magnesium, calcium, strontium and barium is investigated, and the reaction products are described and characterised by X-ray diffraction. Ternary intercalation compounds were synthesised only in the graphite-lithium-calcium system. In the other systems, binary compounds were obtained. The co-intercalation of sodium and the alkaline earth metals calcium, strontium and barium is studied too. No ternary compounds were obtained. However, in the case of the sodium-barium system, a discussion on ternary graphite-sodium-barium compounds previously published is opened. Several data are in favour of a graphite-sodium-oxygen compound instead of a graphite-sodium-barium one. (C) 2004 Elsevier Ltd. All rights reserved.