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: Perform ab initio calculations to parameterize energetics on the perovskite lattice and use Monte Carlo simulations to study the LSM thermokinetics and cation demixing. Gradients in P(O2) drive demixing, but we need cation thermokinetics for prediction µO µLa µSr (La1-xSrx)MnO3±δ P(O2) Air Electrolyte Kinetic Monte Carlo determination of La, Sr diffusion constants Ab Initio energetics of defect formation, interaction, hopping + empirical defect models jV_A jLa jSr Model the rate of demixing as a function of realistic SOFC operating conditions