Preparation, structure, and electrical conductivity of fluorine-graphite intercalation compound

Abstract

Fluorine-graphite intercalation compound (GIC) has been prepared from pitch-based carbon fiber and powdery natural graphite in the presence of silver fluoride. Prepared compounds are stage 2: C 5–8F, stage 2 + 3: C 8–9F, stage 3: C 9–12F and stage 4: C 13–17F. The rate of fluorine intercalation in graphite is larger in the present system than in other metal fluorides examined previously. X-ray diffraction data indicate that C x F belongs to a hexagonal system with a superlattice of a 0 = 2 a g in the ab plane, accompanying some amount of a bi-intercalation phase. Lattice parameters of stage 3 C 10.9F were a 0 = 4.921 A ̊ , c 0 = 12.733 A ̊ , and those for stage 3 C 8.6F were a 0 = 4.918 A ̊ , c 0 = 12.817 A ̊ . The difference in lattice parameters arises from the increase in electron transfer from carbon to fluorine. The ideal composition of C x F is expressed as C 4 n F ( n = stage number). The highest electrical conductivity is given at stage 3, being 2.3 × 10 4 Scm −1, which is about eight times a pristine pitch fiber.