The Electrical Conductivity of Graphite Filaments and Their Alkali-metal Intercalation Compounds

A bundle of carbon filaments, each about 20 cm in length and 7 μm in diameter, could be grown from purified graphitic material in argon plasma generated in a d.c. arc. The filaments were converted into softer filaments on heat-treatment to 3000–3400 °C. The filaments formed intercalation compounds of potassium, rubidium, and caesium. The electrical resistivities were found to be 1300, 610–660, 23–25, and 28–30 μΩ cm at 300 K for the original filament, the heat-treated filament, and the first stage golden and the second stage dark-blue intercalation compounds of the heat-treated filament, respectively.