Phase and Microstructural Stability of Electrolyte Matrix Materials for Molten Carbonate Fuel Cells

Abstract

LiAlO2 powder is used as a material for molten‐carbonate fuel cell (MCFC) matrices. The physical and chemical stabilities of LiAlO2 powder during MCFC operation determine the performance and lifetimes of the cells. Change to the phase and particle size in the allotropic phase of LiAlO2 was examined with long‐term stability tests on pure α‐LiAlO2 matrix, Al‐reinforced α‐LiAlO2 matrix, Al‐reinforced γ‐LiAlO2 matrix, aqueous γ‐LiAlO2 matrix and an α‐/β‐LiAlO2 mixture powder in molten carbonate at 650 °C in air. In the γ‐LiAlO2 and α‐/β‐LiAlO2 mixture, the particle growth was continuous from the early stages of heat‐treatment to 20,000 h. Crystalline phase transformation (γ‐LiAlO2 and β‐LiAlO2 to α‐LiAlO2 and γ‐LiAlO2, respectively) of these powders and matrices also occurred, and γ‐LiAlO2 made the third phase like LiAl5O8. By contrast, the sizes of these particles and the crystalline phase of α‐LiAlO2 did not change during immersion tests. These results show that, among α‐/β‐ and γ‐LiAlO2, α‐LiAlO2 is the most stable phase in molten carbonate.

Effect of Dopant Concentrations on the Luminescent Properties of LiAl5O8:Fe Phosphors

“…[6][7][8][9] The intense emission and high luminescence efficiency are mainly related to the combination of the host matrix and the properties of the luminescent center. [10] A wide range of compounds are suitable for this purpose, such as the aluminate group, which has been the subject of several studies in recent years. [5,11,12] In this class of materials, lithium aluminate (LiAl 5 O 8 ) is seen as a promising host as reported in several recent works.…”

Development and Performance Test of Molten Carbonate Fuel Cell Stack

“…Therefore, a reasonable porosity and pore size distribution of the matrix is required. Generally, the porosity of the matrix is 50-70%, the pore size is less than 1 µm, and the distribution is uniform [6][7][8][9][10] .…”

LiAlO2/LiAl5O8 Membranes Derived from Flame-Synthesized Nanopowders as a Potential Electrolyte and Coating Material for All-Solid-State Batteries

“…LiAlO 2 has been reported to be a good candidate for carbonate fuel cells as an electrolyte matrix, as a substrate for growing GaN epitaxial film, and as a catalyst for biodiesel production . LiAlO 2 has also been used as a ceramic filler for polymer electrolytes .…”