1. Ab-Initio Based Thermokinetic Modeling of Cation Demixing in La1-xSrxMnO3±δ
Dane Morgan, Department of Materials Science and Engineering, University of Wisconsin-Madison
Motivation: La1-xSrxMnO3±δ (LSM) demixing potentially influences the cathode performance for Solid Oxide Fuel Cells (SOFC) .
Approach: Use ab initio parameterized kinetic Monte Carlo (KMC) simulations to calculate diffusion coefficients. Combine with a defect model to calculate cation fluxes and determine demixing.
Ab Initio parameterized
KMC hamiltonian
Diffusion coefficients from KMC
+ Defect model for chemical potential gradients
Sr-V repulsion decreases Sr diffusion µO
µLa
µSr
(La1-xSrx)MnO3±δ
P(O2)
Air
Electrolyte
jV_A
jLa
jSr
Defect model predicts
dμLa/dx > μSr/dx, further reducing Sr segregation
Vac Sr La
Predict demixing at SOFC conditions: La segregation to high P(O2) surface