Hello, A new project on the LCRC cluster has been requested. Please forward the information on to the LCRC Allocation sub-committee. Applicant's name: hakim iddir Applicant's institution: ANL Applicant's division: MSD Project Name: CMD Project title: Cathode Materials and Dissolution Associated funding: EERE Other Systems: Science: Previous experimental studies have shown a facet dependent segregation of transition metals (TM) in Li(Ni1-x-yMnxCoy)O2 (NMC) crystals.1 However, it is not clear yet the mechanism and driving forces for such process. It is expected that the local segregation of transition metals would change the properties of these surfaces and the material in general. For example, changes in chemical composition of these surfaces would affect the reactivity toward electrolyte oxidation and the transition metal dissolution. The dissolution of transition metals from the cathode and the subsequent effect in the anode is recognized as one of the challenges to reach a deeper understanding of the battery performance. Also, the dissolution of transition metals from the cathode is closely related with oxidation/reduction of electrolytes species that could also migrate across the cell and reach the other electrode surface and induce further reactions. In order to prevent th e transition metal dissolution or mitigate its deposition, a deeper understanding of the segregation of species and the subsequent dissolution process is needed. Project description: We plan to perform DFT calculations to gain insights in the transition metal segregation process to NMC surfaces. We have already found facet dependent changes in the electronic structures of these surfaces.3 We have also found evidence of a driving force for segregation of Co to specific facets of NMC particles. The segregation of Ni is underway, and present some challenges. In order to compute the effect of a segregation profile, larger slab models are needed. Additionally, we found that for a more accurate determination and stability of the complex electronic and magnetic structure of the material, hybrid functionals must be used. Hence, we will use density functional theory (DFT) at the GGA+U level, to determine the initial configurations and further apply the more computationally expensive hybrid functional to get more accurate electronic configurations. Specifically, we will use a method based on the Heyd−Scuseria−Ernzerhof (HSE06) screened hybrid density functional as implemented in the VASP code. Furthermore, for specific systems we will use our previously developed cluster expansion techniques in order to find low energy configurations.4 Also, we will calculate the segregation effect on transition metal dissolution and its effect in incorporation into the anode SEI. Slab models of surfaces of at least 12 transition metal layers will be needed. We are going to test at least three different states of charge. We will simulate three different facets and explore at least three oxygen coverages for each facet. Testing three different NMC compositions would require a total of 81 set ups. We estimate we will need 15000 computer hours for each set up. Hence, a total amount of 1215000 computer hours would be required to accomplish this project. Our experience, with previous projects using VASP installed on Blues, has shown that the performance, number of nodes needed and capabilities of the Blues and Bebop cluster a re suitable for the type of calculations we propose in this project. References (1) Yan, P.; Zheng, J.; Zheng, J.; Wang, Z.; Teng, G.; Kuppan, S.; Xiao, J.; Chen, G.; Pan, F.; Zhang, J.-G.; Wang, C.-M. Ni and Co Segregations on Selective Surface Facets and Rational Design of Layered Lithium Transition-Metal Oxide Cathodes. Adv. Energy Mater. 2016, 6 (9), n/a-n/a. (2) Xu, K. Electrolytes and Interphases in Li-Ion Batteries and Beyond. Chem. Rev. 2014, 114 (23), 11503–11618. (3) Garcia, J. C.; Bareño, J.; Yan, J.; Chen, G.; Hauser, A.; Croy, J. R.; Iddir, H. Surface Structure, Morphology, and Stability of Li(Ni1/3Mn1/3Co1/3)O2 Cathode Material. J. Phys. Chem. C 2017. (4) Lee, E.; Iddir, H.; Benedek, R. Rapidly Convergent Cluster Expansion and Application to Lithium Ion Battery Materials. Phys. Rev. B 2017, 95 (8), 085134. Industry partnership: Project URL: Requested allocation: 1215000 Q1: 200000 Q2: 300000 Q3: 300000 Q4: 415000 Justification: Slab models of surfaces of at least 12 transition metal layers will be needed. We are going to test at least three different states of charge. We will simulate three different facets and explore at least three oxygen coverages for each facet. Testing three different NMC compositions would require a total of 81 set ups. We estimate we will need 15000 computer hours for each set up. Hence, a total amount of 1215000 computer hours would be required to accomplish this project. Our experience, with previous projects using VASP installed on Blues, has shown that the performance, number of nodes needed and capabilities of the Blues and Bebop cluster are suitable for the type of calculations we propose in this project. Storage requirements: 1 TB The requester has used undetermined amount hours of their initial startup project. In addition to approving an initial amount, please specify a Category and Subcategory for this project. For a list of the current selection of approved categories, please see: https://wiki.lcrc.anl.gov/wiki/Processes/Categories Once the Allocation committee has approved the project, please go to the Project Management page to create it: https://accounts.lcrc.anl.gov/projects.php Thank You, The LCRC Accounts System