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

Heo, Su Jeong; Hu, Boxun; Manthina, Venkata; Hilmi, Abdelkader; Yuh, Chao‐Yi; Surendranath, Arun; Singh, Prabhakar P.

doi:10.1016/j.ijhydene.2016.03.145

Cited by 25 publications

(12 citation statements)

References 41 publications

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“…For the peak fitting of the acquired XPS spectra, the binding energy of the Al 2p states of Al metal and LiAl were set to 72.9±0.1 eV and 71.6±0.1 eV, respectively, whereas the binding energies of Li 1+ x Al and Li x AlO y were not fixed as their position is indicative of the lithiation degree of both species. The binding energy of Al metal was based on a previous report by Singh and co‐workers . According to in situ XRD measurement results, LiAl formation (incipient lithiation: Al+e − +Li + →LiAl) starts at approximately 200 mAh g −1 .…”

Section: Methodsmentioning

confidence: 67%

“…The binding energy of Al metal was based on ap revious report by Singh and co-workers. [26] According to in situ XRD measurement results, LiAl formation (incipient lithiation:A l + e À + Li + !LiAl) starts at approximately 200 mAh g À1 . Therefore, the alloy in the inner part of the Al electrode at this stage should be LiAl, which is located at 71.6 eV as shown in Figure 4a.F inally,a ny Al 2p peak with ab inding energy higher than 75.0 eV is ascribed to Al 2 O 3 ,w hereas states below 71.6 eV are ascribed to over-lithiated alloys.…”

Section: Electrodemorphologyand Surface Chemistry Characterizationmentioning

confidence: 99%

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Revisiting the Electrochemical Lithiation Mechanism of Aluminum and the Role of Li‐rich Phases (Li_1+xAl) on Capacity Fading

et al. 2019

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Aluminum is an appealing anode material for high‐energy‐density lithium‐ion batteries (LIBs), owing to its low cost, environmental benignity, high specific capacity, and lower relative volume expansion compared with other alloying materials. However, both, the working and capacity fading processes are not yet consistently and comprehensively understood, which has largely hindered its development. In this study, the electrochemical alloying process of aluminum anodes with lithium is systematically studied by the combination of several in situ and ex situ techniques, providing new insights into phase transitions, electrode dynamics, and surface chemistry. Particular attention is paid to the role of the Li‐rich alloys (Li1+xAl). Its existence on the surface of the Al electrode is unexpectedly observed, and its growth in the electrode bulk is found to be strictly correlated with cell failure. Interestingly, cell failure can be delayed by choosing an appropriate electrolyte. This work contributes to a solid and comprehensive understanding of the puzzling Al (de‐)lithiation processes, which is fundamental and highly enlightening for future research work on Al and other alloyed anodes.

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Section: Methodsmentioning

confidence: 67%

Section: Electrodemorphologyand Surface Chemistry Characterizationmentioning

confidence: 99%

Revisiting the Electrochemical Lithiation Mechanism of Aluminum and the Role of Li‐rich Phases (Li_1+xAl) on Capacity Fading

et al. 2019

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“…In batteries, LiAlO 2 nanocrystals and mesoporous materials are critical components in the electrolyte composites . In molten carbonate fuel cells (MCFCs), LiAlO 2 is used as the electrolyte matrix . In fusion energy, LiAlO 2 is a candidate material for producing tritium in a tritium breeder blanket .…”

Section: Introductionmentioning

confidence: 99%

Role of interfaces in damage process of irradiated lithium aluminate nanocrystals

Senor

Devanathan

2018

J Am Ceram Soc

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Molecular dynamics simulations were performed to understand the differences in the response of single crystal and nanocrystalline γ‐LiAlO2 to energy deposition by 10 keV Li recoils. The simulations are performed at 573 K and focus on the damage production in the absence of thermal annealing. The grain boundaries in the nanocrystals are found to be amorphous. Analyses of the fate of the beam ions show that the amorphous grain boundaries and differently oriented nanograins increase the number of backscattered ions and decrease the number of transmitted ions. Damaged regions protruding from the grain boundaries provide a direct evidence of the role of the grain boundaries as scattering centers in collision cascades. The simulations show that the defect density produced in the nanocrystals is about twice that in the single crystals. In both samples, Li defects account for 70% of the defects, demonstrating that LiO4 tetrahedra are much more susceptible to damage than AlO4 tetrahedra. Furthermore, Li defects occur preferentially near grain boundaries. Diffusion simulations confirm the limited thermal diffusion of defects at 573 K, effectively separating the damage production from thermal annealing in the irradiation simulations. Nevertheless, the mean square displacements of grain‐boundary defects are found to be larger than lattice defects and surface defects.

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“…24 The pellet was prepared by uniaxial dry-pressing under 200 MPa and then filled with 52Li 2 CO 3 -48Na 2 CO 3 electrolyte (100% void volume) at 700…”

Section: Methodsmentioning

confidence: 99%

Role of Exposure Atmospheres on Particle Coarsening and Phase Transformation of LiAlO₂

Heo

Uddin

et al. 2017

J. Electrochem. Soc.

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The phase transformation and particle coarsening of lithium aluminate (α-LiAlO 2 ) in electrolyte are the major causes of degradation affecting the performance and the lifetime of the molten carbonate fuel cell (MCFC). The stability of LiAlO 2 has been studied in Li 2 CO 3 -Na 2 CO 3 electrolyte under accelerated conditions in reducing and oxidizing gas atmospheres at temperatures of 650 and 750 for up to 500 hours. X-ray diffraction analyses show that the progressive transformation of α-LiAlO 2 to γ-LiAlO 2 phase proceeds with increasing temperature in lower P CO 2 and lower P O 2 environments. Spherical LiAlO 2 particles were transformed to coarsened pyramid-shape particles in 4% H 2 -3% H 2 O-N 2 and 100% N 2 (∼10 ppm P O 2 ) atmospheres. Under CO 2 -rich atmospheres (4% H 2 -30% CO 2 -N 2 and 70% air-30% CO 2 ), both phase and particle size remained unchanged at 650 and 750 • C. Selected area electron diffraction (SAED) pattern analysis indicated that the large pyramidal shape particles (∼30 μm) were γ-LiAlO 2 phase. Experimental observations and related simulation results pertaining to particle coarsening and phase transformation behavior of Molten carbonate fuel cell (MCFC) power generation systems are currently being developed and commercialized because of their demonstrated high electrical efficiency (>45% net electrical AC and >90% combined heat and electric), multi-fuel operational flexibility (pipeline natural gas, bio-gases from farm waste and wastewater treatment), pollution-free operation (no NO x , SO x , PM's, VOC) and reduced CO 2 foot print.1-3 A large number of MCFC power plants in multi -MWe class have been successfully installed and operated in North America, Europe and Asia demonstrating the technology and systems engineering robustness. 4 Over the last decade, optimization of cell and stack operating conditions, materials chemistry and fabrication processes have resulted in significant improvement of the cell life and performance making it possible to obtain long life (>50,000 hrs.) of MWe class systems.5 A need to increase the system life time to >80,000 hours has been identified as next steps for increased market penetration and cost reduction. 6 For the state of the art MCFC's, the electrical performance degradation is commonly assigned to cell and stack component corrosion, structural changes, and electrolyte loss. Although effective mitigation strategies for a number of materials related degradation issues (anode creep, cathode dissolution, current collectors and bipolar plate corrosion) have been developed and implemented, 7,8 challenge with matrix coarsening beyond 60,000 hours remains.The lithium aluminate (LiAlO 2 ) is the state-of-the-art ceramic constituent material in the electrolyte matrix. It effectively retains the liquid electrolyte and prevents gas crossover with sufficient finepore structure stability.9 LiAlO 2 exists in three different allotropic forms which are hexagonal α-LiAlO 2 (ρ = 3.401 g/cm 3 ), monoclinic β-LiAlO 2 (ρ = 2.615 g/cm 3 ), and tetragonal γ-LiAlO 2 (ρ...

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

Cited by 25 publications

References 41 publications

Revisiting the Electrochemical Lithiation Mechanism of Aluminum and the Role of Li‐rich Phases (Li_1+xAl) on Capacity Fading

Revisiting the Electrochemical Lithiation Mechanism of Aluminum and the Role of Li‐rich Phases (Li_1+xAl) on Capacity Fading

Role of interfaces in damage process of irradiated lithium aluminate nanocrystals

Role of Exposure Atmospheres on Particle Coarsening and Phase Transformation of LiAlO₂

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

Cited by 25 publications

References 41 publications

Revisiting the Electrochemical Lithiation Mechanism of Aluminum and the Role of Li‐rich Phases (Li1+xAl) on Capacity Fading

Revisiting the Electrochemical Lithiation Mechanism of Aluminum and the Role of Li‐rich Phases (Li1+xAl) on Capacity Fading

Role of interfaces in damage process of irradiated lithium aluminate nanocrystals

Role of Exposure Atmospheres on Particle Coarsening and Phase Transformation of LiAlO2

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Revisiting the Electrochemical Lithiation Mechanism of Aluminum and the Role of Li‐rich Phases (Li_1+xAl) on Capacity Fading

Revisiting the Electrochemical Lithiation Mechanism of Aluminum and the Role of Li‐rich Phases (Li_1+xAl) on Capacity Fading

Role of Exposure Atmospheres on Particle Coarsening and Phase Transformation of LiAlO₂