Small Seebeck coefficient of graphite intercalation compounds containing CaC_6

摘要

Calcium graphite intercalation compounds (Ca-GICs; the composition is CaC_6) and GICs containing CaC_6 are synthesized from Grafoil and PGS graphite sheets, and the Seebeck coefficients are measured. The absolute values of the Seebeck coefficient of these GICs are very small; in some cases, the values are positive. This phenomenon observed in the Seebeck coefficient of GICs containing CaC_6 is very different from that of general GICs such as alkali-metal GICs. The temperature dependence of the Seebeck coefficient of these GICs is to that of general GICs; that is, the absolute values of the Seebeck coefficient decrease with a decrease in the temperature.