ChemInform Abstract: Electrochemical Characteristics of Fluorinated Activated Carbon Fibers-Lithium Cells.

ChemInform Abstract

Activated carbon fibers (ACF's), fluorinated at low temp. (20-200 °C) under F2 pressures of 100-760 torr, have been investigated as cathode materials for Li cells in 1 M LiClO₄-propylene carbonate solutions. An increase in the fluorination temp. from 20 to 200 °C results in an decrease of the open-circuit voltage of the cathodes from 3.68 to 3.35 V, which is ascribed to the change ofthe nature of the C-F bond from chemisorption through charge transfer to covalent bond. Discharge performance, particularly the stability of discharge potential and cathode utility, are significantly improved by higher fluorination temperatures. Fluorinated ACF's obtained at 200 °C but with reduced F2 pressure have stable discharge potentials which are 0.5 V higher than that of conventional graphite fluoride, (CF)n. The cathode utilization is higher than 70%.