Intercalation and electrical properties of graphite fibers with thermal and air stability

摘要

Vapor-grown carbon fibers have been obtained by pyrolysis of hydrocarbons, such as benzene and methane, by a catalytic effect of ultrafine metal particles(i). Two different methods, have been developed for successful formation of the fibers, the substrate method and the aerogel system(1)(2)(3).By the substrate method, thick(/spl tilde/10/spl mu/m diameter) and long fibers(/spl tilde/20cm long) can be grown. By the aerogel system, where the catalytic particles are floating in the reaction chamber, very thin fibers of less than 1/spl mu/m in diameter and less than several mm in length have been effectively produced. From gas phase, these carbon fibers have a high degree of preferred orientation and exhibit a high degree of graphitizability high enough for intercalation. The intercalated vapor-grown carbon fibers show high electrical conductivity and mechanical performance. By choosing suitable intercalants, air and thermally stable compounds can be obtained. These compounds are applicable for practical application as a light weight conductor in plastic composites. In the present paper, the preparation and electrical properties of bromine intercalated vapor-grown carbon fibers having air and thermal stability are shown, and the electronic structure giving rise to the high conductivity is discussed.