Role of Exposure Atmospheres on Particle Coarsening and Phase Transformation of LiAlO2. Issue 8 (1st January 2017)

• Record Type: Journal Article
• Authors: Heo, Su Jeong; Hu, Boxun; Uddin, Md Aman; Aphale, Ashish; Hilmi, Abdelkader; Yuh, Chao-Yi; Surendranath, Arun; Singh, Prabhakar
• Is Part Of: Journal of the Electrochemical Society. Volume 164:Issue 8(2017)
• Page Start: H5086
• Page End: H5092
• Publication Date: 2017-01-01
• Subjects: Lithium aluminate -- Molten carbonate fuel cell -- Particle coarsening -- Phase transformation -- Stability; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0181708jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : The phase transformation and particle coarsening of lithium aluminate (α-LiAlO2 ) in electrolyte are the major causes of degradation affecting the performance and the lifetime of the molten carbonate fuel cell (MCFC). The stability of LiAlO2 has been studied in Li2 CO3 -Na2 CO3 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-LiAlO2 to γ-LiAlO2 phase proceeds with increasing temperature in lower P CO2 and lower P O2 environments. Spherical LiAlO2 particles were transformed to coarsened pyramid-shape particles in 4% H2 -3% H2 O-N2 and 100% N2 (∼10 ppm P O2 ) atmospheres. Under CO2 -rich atmospheres (4% H2 -30% CO2 -N2 and 70% air-30% CO2 ), 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-LiAlO2 phase. Experimental observations and related simulation results pertaining to particle coarsening and phase transformation behavior of LiAlO2 are presented.