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Title: Role of Exposure Atmospheres on Particle Coarsening and Phase Transformation of LiAlO 2

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 2CO 3-Na 2CO 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 CO2 and lower P O2 environments. Spherical LiAlO 2 particles were transformed to coarsened pyramid-shape particles in 4% H 2-3% H 2O-N 2 and 100% N 2 (~10 ppm P O2 ) 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 750ºC. The 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 LiAlO 2 are presented.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [2] ;  [1]
  1. Univ. of Connecticut, Storrs, CT (United States). Center for Clean Energy Engineering and Dept. of Materials Science and Engineering
  2. FuelCell Energy, Inc., Danbury, CT (United States)
Publication Date:
Grant/Contract Number:
EE0006606
Type:
Accepted Manuscript
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 164; Journal Issue: 8; Journal ID: ISSN 0013-4651
Publisher:
The Electrochemical Society
Research Org:
FuelCell Energy, Inc., Danbury, CT (United States); Univ. of Connecticut, Storrs, CT (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Lithium aluminate; Molten carbonate fuel cell; Particle coarsening; Phase transformation; Stability
OSTI Identifier:
1425155