Reinforcement of molten carbonate fuel cell matrixes by adding rod-shaped γ-LiAlO2 particles

Improvement in strength of gamma -LiAlO2 matrixes for a molten carbonate fuel cell (MCFC) via addition of rod-shaped gamma -LiAlO2 particles has been investigated. The rod-shaped gamma -LiAlO2 particles with the aspect ratio of 9-15 were obtained by heat-treating rod-shaped beta -LiAlO2 particles at 800 degreesC for 3 h, synthesized from the reaction mixture of LiOH-gamma -Al2O3-NaOH. The gamma -form was very stable for more than 700 h in a molten carbonate environment at 650 degreesC, while the beta -form showed both a phase change from beta- to gamma -LiAlO2 and a morphology change from rod- to bipyramid-shapes. The average pore size and the porosity of the matrix (550 mum thickness) fabricated by tape-casting of the slurry with weight ratio 1.0 of rod-shaped gamma -LiAlO2 particles to commercial gamma -LiAlO2 powders (2.0 mum dia.) were about 0.12 mum and 54%, respectively, after being heat-treated at 650 degreesC for 2 h. The strength (197 g(f)/mm(2)) of the rod- shaped particle reinforced matrixes was enhanced more than twice as much as that of the non-reinforced gamma -LiAlO2 matrixes (91 g(f)/mm(2)). (C) 2001 Kluwer Academic Publishers.