FLUORINE-INTERCALATED CARBON-FIBERS .1. STRUCTURAL AND TRANSPORT-PROPERTIES

The intercalation of fluorine in various types of carbon fibers (PAN-b ased or pitch-based, as-received or high-temperature treated) has been investigated at room temperature in the presence of gaseous HF. Stage -1 compounds with C2.5F to C4F compositions are obtained for 10 bar F- 2 pressures, whereas lower pressures (1 bar F-2) lead to stage-2 compo unds. Although in higher stages (greater than or equal to 2) the elect rical conductivity is generally larger than in the pristine fiber, in stage-1 compounds a drastic increase of resistivity is observed, rho b eing more than one order of magnitude larger than that of the starting material. Finally, fluorine-intercalated GICs have been found appropr iate to investigate the effects of disorder and reduced dimensionality .