Synthesis of fine particle size lithium aluminate for application in molten carbonate fuel cells

Kinoshita, K.; Sim, J. W.; Kucera, G.H.

doi:10.1016/0025-5408(79)90016-3

Cited by 13 publications

(6 citation statements)

References 3 publications

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“…A number of recent studies, however, have shown that the c-LiAlO 2 undergoes particle growth, and the crystal phase of a-LiAlO 2 in the matrix is more stable than c-LiAlO 2 during MCFC operation [5][6][7]. Although a-LiAlO 2 is the most stable in molten carbonate, however, it does require expensive raw materials and a complicate fabrication process [3,8,9] all of which raise the unit MCFC manufacturing cost.…”

Section: Introductionmentioning

confidence: 96%

Cost‐effective Synthesis of α‐LiAlO₂ Powders for Molten Carbonate Fuel Cell Matrices

et al. 2009

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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‐LiAlO2 was partially transformed to α‐LiAlO2. In the second method, molten salts (Li2/Na2/K2CO3) 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 α‐LiAlO2 were suitable for reinforcing the matrix and tape casting. Lastly, this study examined the effect of CO2 for the synthesising of α‐LiAlO2 particles.

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Section: Introductionmentioning

confidence: 96%

Cost‐effective Synthesis of α‐LiAlO₂ Powders for Molten Carbonate Fuel Cell Matrices

et al. 2009

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“…A number of synthesis processes including conventional solid-state reactions, sol-gel processing, co-precipitation and combustion synthesis have been extensively used for the preparation of LiAlO 2 powder. Solid-state synthesis in the range of 370°C to 1000°C has been reported to lead to the formation of a mixture of LiOH and a lithium dialuminate, depending on the calcination temperature [13,14]. The process was found difficult for the synthesis of pure lithium aluminate with controlled size and morphology due to partial evaporation of lithium at higher temperatures and contamination from grinding operations [15].…”

Section: Introductionmentioning

confidence: 99%

Stability of lithium aluminate in reducing and oxidizing atmospheres at 700 °C

Heo

Manthina

et al. 2016

International Journal of Hydrogen Energy

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The stability of lithium aluminate (LiAlO 2) powders has been studied under reducing (4% H 2-N 2) and oxidizing (Air) atmospheres at 700ºC. While XRD results show the raw α-LiAlO 2 samples contain a minor fraction of LiAl 2 (OH) 7 •2H 2 O and LiAlO 2 0.25H 2 O phases, high-temperature XRD study shows that LiAl 2 (OH) 7 •2H 2 O may have decomposed at 700ºC to γ-LiAlO 2 and LiAlO 2 0.25H 2 O to α-LiAlO 2. Surface morphological studies show the samples consist of porous LiAlO 2 spherical agglomerates with interconnected nanoparticles. The XPS analyses indicate that the powder surface Li/Al ratio decreases after exposure to reducing atmosphere whereas much less change to the oxidizing atmosphere. The binding energy of Al 2p peak also changes in the high-temperature reducing and oxidizing environments, indicating the presence and coexistence of different oxidation states of Al species on the surface. The color of LiAlO 2 powder, examined visually, changed from white to gray after reduction and back to white after re-oxidation, indicating the likelihood of generation of non-stoichiometry under reducing atmosphere.

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“…The main materials of Al-reinforced matrices like c-LiAlO 2 or a-LiAlO 2 act as catalysts in the phase transformation. Figure 4 shows that the c-LiAlO 2 phase in Al-reinforced c-LiAlO 2 matrices was stable until 10,000 h, even though a small amount of the a-LiAlO 2 phase was created after 500 h. Unlike the phase transformation shown in Figure 3, the c-LiAlO 2 in Figure 4 did not change to a-LiAlO 2 [8]. The intensity ratio of a-/c-phase was too small to change the c-phase to the a-phase, therefore the a-phase could not effect the c-phase in these matrices as a seed, and c-LiAlO 2 lost its stability before 18,000 h. Terada et al [1] showed that Li + ions are dissolved from LiAlO 2 according to the following reaction:…”

Section: Crystalline Phase Stability Of Lialomentioning

confidence: 55%

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

et al. 2010

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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.

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Synthesis of fine particle size lithium aluminate for application in molten carbonate fuel cells

Cited by 13 publications

References 3 publications

Cost‐effective Synthesis of α‐LiAlO₂ Powders for Molten Carbonate Fuel Cell Matrices

Cost‐effective Synthesis of α‐LiAlO₂ Powders for Molten Carbonate Fuel Cell Matrices

Stability of lithium aluminate in reducing and oxidizing atmospheres at 700 °C

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

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Synthesis of fine particle size lithium aluminate for application in molten carbonate fuel cells

Cited by 13 publications

References 3 publications

Cost‐effective Synthesis of α‐LiAlO2 Powders for Molten Carbonate Fuel Cell Matrices

Cost‐effective Synthesis of α‐LiAlO2 Powders for Molten Carbonate Fuel Cell Matrices

Stability of lithium aluminate in reducing and oxidizing atmospheres at 700 °C

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

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Product

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Cost‐effective Synthesis of α‐LiAlO₂ Powders for Molten Carbonate Fuel Cell Matrices

Cost‐effective Synthesis of α‐LiAlO₂ Powders for Molten Carbonate Fuel Cell Matrices