Preparation and electrical conductivity of fluorine-graphite fiber intercalation compound

Abstract

Fluorine-graphite fiber intercalation compounds were prepared in the presence of copper fluoride, and their electrical conductivities and stability were evaluated. Major products were a mixture of the 2nd and 3rd stages or the 3rd stage with intercalate 12–16 wt% corresponding to C 8–12F. A mixture of the 3rd and 4th stages contained 8–12 wt% intercalate corresponding to C 12–18F. No 1st and pure 2nd stage compounds were prepared under the present condition (F 2:1 atm, 10 days). The highest electrical conductivities at room temperature were 1.1 × 10 5 2.0 × 10 4 and 7.0 × 10 3 Scm −1 for VGCF, pitch fiber and PAN fiber-based GIC's, respectively. They were 8.5, 8 and 6 times those of the pristine fibers. The decrease in the conductivity in air was less than 18% after 100 days for PAN fiber-based GIC, and 30% after 130 days for pitch fiber-based GIC. However, VGCF-based GIC decomposed to graphite after 1 month. DTA and TG analyses showed that the decomposition of GIC to a high stage compound started at 150°C, and the high stage GIC started to decompose to graphite at 360–390°C for PAN and pitch fiber-based GIC's. VGCF-based GIC decomposed at lower temperatures than those of other two fibers.