Synthesis and stability of Br 2, ICI and IBr intercalated pitch-based graphite fibers

Abstract

This work presents a further study of the intercalation of halogens in pitch-based fiber and the stability of the resultant intercalation compounds. P-100 fibers were intercalated with purified IBr at 50 °C to produce high electrical conductivity graphite intercalation compounds (GICs). After intercalation and subsequent equilibration in ambient atmosphere, the fibers average a five-fold conductivity,enhancement over the pristine fiber, and after nine weeks in air, the conductivity, σ, degrades by only 1%. The intercalation of ICl in P-100 was performed in vacuum-sealed vessels at 50 °C, 20° and 0 °C. Both the lowest equilibrium resistivity and its smallest ambient gain were observed for fibers reacted at 20 °C. P-100 brominated at 68 °C in vacuum-sealed vessels showed no loss in electrical and stability properties over those reacted at 20 °C in the presence of air. Energy dispersive spectroscopy (EDS) results confirm the existance of excess bromine and chlorine in the iodine interhalide GICs, which is predicted by the oxidation mechanism proposed for this class of intercalation reactions.