Causes of high and stable electrical conductivity in graphite intercalation compounds prepared from flexible graphite sheets

摘要

Various materials such as alkali-metal atoms, metal halides, and halogen molecules, can intercalate into the interlayers of lamellar graphite and form graphite intercalation compounds (GICs). A result of this intercalation is the occurrence of the carrier transfer between intercalated materials and adjacent graphite planes (graphene), causing the electrical conductivities of GICs to become approximately ten times higher than those of the host graphite materials. However, it is known that GICs are generally unstable in air. Most GICs are immediately decomposed by oxidation or the de-intercalation of intercalated materials when exposed to the atmosphere. We have been investigating the stability of GICs and have succeeded in the formation of air-stable GICs exhibiting high electrical conductivity. Recently, we have reported that K-GICs prepared from commercially available flexible graphite sheets (PGS) exhibit high stability and high electrical conductivity for an extended period of time in air. However, we were unable to thoroughly explain the stabilization mechanism.