Carbon monofluorides derived from sponge and shot cokes

Abstract

Carbon fluoride compounds, CFx, are used as cathode materials in commercially important primary Li/CFx electrochemical power sources. New CFx compounds were prepared, apparently for the first time, from sponge and shot cokes by direct fluorination. The carbon starting materials and CFx products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and elemental analysis for total fluorine. The discharge capacity of shot coke CFx was unexpectedly low and is probably related to the heterogeneous nature of that form of coke. CFx prepared from sponge coke that had been heated to 1930 °C exhibited the highest capacity, exceeding the capacity of a commercially available, battery grade CFx. The discharge results show that CFx from heated sponge coke has favorable electrochemical properties that render it attractive for lithium electrochemical power sources.