(450b) Ab Initio modeling of the Cation Diffusion in La1-XSrxMnO3±δ for Solid Oxide Cell Electrodes Applications

Cation diffusion in La_1-xSr_xMnO_3±δ (LSM) and in related perovskite materials play an important role in controlling performance and long term stability of solid oxide fuel cells and electrolytic cells. In particular, cation transport contributes to the formation of the secondary phases, segregated surface compositions, and diffuse interfaces between cell components. Fundamental mechanistic understanding and quantitative theoretical model predictions on cation diffusivity in LSM are still insufficient to accurately reproduce experimental cation diffusivity measurements. In this work, based on ab initio based LSM defect modelling [1] we determined the defect interaction energies for defect clusters involved in cation diffusion, and the migration barriers of candidate diffusion mechanisms. This data has been further used to calculate the La_0.75Sr_0.25MnO₃ cation self-diffusion coefficients vs. 1/T (T=873~1273 K) from a random-walk diffusion model. The predicted Mn self-diffusion coefficients, along with those of La/Sr cation diffusion [2], will be discussed and compared with experimental tracer diffusion coefficients reported in the literature [3].

[1] Y.-L. Lee and D. Morgan, Phys. Chem. Chem. Phys., 2012, 14, 290â??30

[2] B. Puchala, Y.-L. Lee, and D. Morgan, J. Electrochem. Soc., 160 (8) F877-F882 (2013)

[3] S. P. Harvey, R. A. De Souza, and M. Martin, Energy Environ. Sci., 2012, 5, 5803