Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Peter Zapol Project Name: chemexp Division: MSD Project title: Chemical Expansion in Perovskites Associated funding: DOE BES Other Systems: none Science: The solid oxide fuel cell (SOFC) presents a highly attractive energy conversion option besides the conventional energies as a clean and efficient energy conversion technology. However, the high operating temperature limits its commercial applications. The LaxSr1-xCoyFe1-yO3-delta (LSCF) displaying mixed ionic electronic conductivity serves as a promising cathode material for intermediate-temperature SOFCs. For the LSCF perovskite materials, the oxygen stoichiometry plays a critical role in the materials performance characteristics. Recently experiments showed that the oxygen stoichiometry can be investigated usingg x-rays under applied electrical potentials across the LSCF/YSZ (yttria-stabilized zirconia) heterostructures. The change in the oxygen vacancy concentration leads to a significant dilation or contraction of the lattice known as chemical expansion, which gives a way to investigate thermodynamic and kinetic effects arising from oxygen reduction reaction. U nderstanding the in-situ lattice changes with the bias voltage is critical because it sheds light on operation of the SOFC at different potantials and in different chemical environments. Collaborating with the experimentalists at Argonne, we will carry out a series of researches to compare and explain the experiment results. Project description: project description Previously we have performed calculations using density functional theory to explore the lattice changes with the oxygen stoichiometry in the bulk and on the surface of LSCF. Next, we will explore thin films and the oxygen vacancy migration across the LSCF/YSZ interface and in the thin film LSCF in the presence of ambient air species. The projector augmented plane-wave method as implemented in the Vienna ab initio simulation package (VASP) will be employed to find the optimized structures of surface species interacting with different oxygen vacancy configurations. VASP is a well validated code which is installed at LCRC and is widely used for this type of calculations with good performance. We have performed a number of tests on the BEBOP with Broadwell nodes. We will use 4 Broadwell nodes (144 cores) per calculation. The climbing image nudged elastic band method (NEB) will be used to study the oxygen vacancy migration and surface reactions of ambient species. We plan to d o calculations of different oxygen vacancy concentrations for surface cells corresponding to deviation from formal oxygen stoichiometry of 3 by 0.125, 0.25, 0.375, 0.5. For each configuration, we need several calculations to find the optimized ionic positions at fixed in-plane lattice constant. In each calculation, we need about 10 hours of run time when using 4 nodes. For the surface reactions, each NEB calculation is about 30 hours using 144 cores. We need to calculate about 5 NEB points, 4 pathways for the 4 different oxygen vacancy concentrations and 2 different surface species. Therefore, expected time estimate for surface structural optimizations is (36 cores/node * 4 nodes * 10 hours of run time * 16 different runs) 23,000 core-hours and for NEB calculations is (36 cores/node * 4 nodes * 20 hours of run time * 200 different runs)=460,000 core-hours. The total time requested is 480,000 core hours. There will be two to three members in the project Industry partnership: none Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 480000 Q1: 120000 Q2: 120000 Q3: 120000 Q4: 120000 Justification: Storage requirements: default storage allocation is sufficient Thank You, The LCRC Accounts System