A New Carbon Anode Accompanied with Formation Reaction of Intercalation Compound in Fluorine Cell

Abstract

In the operation of fluorine cell, today's essential problems should lower the cell voltage and control the onset of anode effect which is abnormal increase of cell voltage. The cause of above phenomenon is that graphite fluoride of extremely low surface energy is formed on the anode surface by an electrode side reaction. When the electrode surface is partially covered by graphite fluoride, the wettability of anode surface much decreases and the true current density sharply increases. And the anode effect occurs when the value of the surface coverage of the compound reaches to about 0.2.In this paper, the electrochemical characteristics of a new carbon anode are reported. This carbon electrode has been impregnated by molten fluoride at high temperature and high pressure. The cell voltage of the operation with the new anode was much lower than that of the cell with raw carbon electrode, and more the onset of anode effect did not happen even in such a high current density as 60A/dm2. This means that the surfaceof carbon anode is not entirely covered with graphite fluoride, but covered with fluorine intercalation compound which is not so low surface energy and has rather higher electric conductivity than that of raw carbon. This intercalation compound has been identified with the surface analysises.