Theoretical Study of Li- and Na-based Cathode Materials

In this talk, I will discuss our recent efforts to simulate cathode materials for Li-ion and Na-ion batteries. Our recently-developed approach to predict electronic conductivity will be presented. I will then talk about the size-dependence of electronic conductivity in m-NaFePO4 materials. Furthermore, effect of strain on conductivity will be discussed. To study this effect, we applied the concept of the elastic dipole tensor method with ab initio-based parameters. Application of this approach to study electronic and ionic conductivity of LiCoO2 will be presented. In particular, it is shown that the electronic conductivity of LiCoO2 increases with compressive strains, while the ionic conductivity increases with tensile strains. I will finally discuss our results on chemical and mechanical stability of LiNixMnyCo1-x-yO2 cathodes.