SYNTHESIS OF FINE PARTICLE-SIZE LITHIUM ALUMINATE FOR APPLICATION IN MOLTEN CARBONATE FUEL-CELLS

Lithium aluminate (LiAlO2) was synthesized by heat treatment of various types of aluminas (γAl2O3, αAl2O3, γAlOOH, and Al (OH)3), Li2CO3 or LiOH, and Li2CO3K2CO3. For this procedure, the temperature (625 to 975 K) and time (1.5 to 90 h) of heat treatment were varied to determine the optimum conditions to obtain γLiAlO2 of high surface area, which was suitable for electrolyte structures in molten carbonate fuel cells. A mixture of Li2CO3K2CO3 and high-surface area γLiAlO2 was obtained by the heat treatment of γAl2O3, LiOH, and Li2CO3K2CO3 at 775 K for 2 h, then at 975 K for 16 h. However, when γAlOOH, Al (OH)3, and αAl2O3 were substituted for γAl2O3 in the synthesis procedure, α, β, and γLiAlO2 were obtained. A mixture of Li2CO3K2CO3 and a major phase of αLiAlO2 was obtained by heat treatment of alumina, Li2CO3, and Li2CO3K2CO3 at 875 to 975 K for 23 to 90 h; this material is not suitable for electrolyte structures. © 1979.