Fluorinated Graphites as Energetic Cathodes for Nonaqueous Al Batteries

Abstract

Conventional cathodes utilized in nonaqueous lithium anode batteries, including manganese and vanadium oxides, and molybdenum or titanium sulfides, are incompatible with nonaqueous aluminum anode electrochemical storage processes. Alternative cathodes systems were explored to develop high charge capacity nonaqueous aluminum cells. A series of high storage capacity Al cells, utilizing cathodes composed of CF x fluorinated polymer graphite compounds are demonstrated. Significant CF x cathodic capacities are obtained in aluminum anode cells utilizing a 0.3 M tetraethylammonium chloride, 10 mM Hg(CH 3 COO) 2 acetonitrile electrolyte. The addition of hydroxide to the CF x cathode mixture increases discharge potential, while the addition of nonfluorinated 1 μm graphite increases measured cathodic capacity. The CF x cathode capacity increases with the degree of fluorination from 27 to 35% fluorine, is approximately constant from 35 to 58% fluorine, increases in capacity for 61% fluorine, and increases again with 63% fluorine (the highest available level of 63% fluorine available in the CF x ). Measured cathode capacities exceed 250 mAh g - 1 . For example, in excess of 300 mAh g - 1 , total cathode mass is measured for a 50:50 wt % cathode composite containing 55% fluorinated CF x and half 1 μm nonfluorinated graphite.