Cost-effective synthesis of a-LiAlO₂ powders for molten carbonate fuel cell matrices

Lithium aluminate (α-/β-LiAlO₂) particles were fabricated using three methods. The first method used organic glycerin and triethylene glycol which functioned as a catalyst for fabrication of α-LiAlO₂ particles with Al(OH) ₃ and LiOH·H₂O as the starting materials. As a result of the heat-treatment of the starting materials, α-/β-LiAlO₂ particles could be obtained. The amount of α-LiAlO₂ particles in α-/β-LiAlO₂ increased slightly as more organics were added. Additionally, when synthesised α-/β-LiAlO₂ particles were heat-treated in a CO₂ gas flow, β-LiAlO ₂ was partially transformed to α-LiAlO₂. In the second method, molten salts (Li₂/Na₂/ K₂CO ₃) were used as a catalyst to fabricate α-LiAlO₂ as a major phase, however, this method requires a washing process which can produce unexpected impurities. In the third method, pure α-LiAlO₂ was obtained by heat-treatment of cheap sources such as Li₂CO₃ and Al(OH) ₃ at 600-800 °C. The mean particle size (604 nm-11.85 μm) and the specific surface area (3.22-11.4 m² g^-1) of a-LiAlO₂ were suitable for reinforcing the matrix and tape casting. Lastly, this study examined the effect of CO₂ for the synthesising of a-LiAlO₂ particles.