First principle study of lithium diffusion pathways in layered oxide Li2La(TaTi)O7

Layered oxides, as the Ruddlesden-Popper family, have the potential to be a good lithium-ion conductor as solid electrolytes for lithium ion batteries. Recently, new family member, the layered Li2La(TaTi)O7 has been successfully synthesized [1] and its ionic conductivity has been examined. Our first principle calculations reveal the orientation of lithium diffusion pathways and the energy barriers in these pathways, which are directly correlated with the atomic arrangement of this material. We also found that the energy barriers will be lowered with Li deficiency, indicating that introducing lithium defects can also improve the lithium diffusion, and therefore the ionic conductivity, agreement with our experimental observations. These results have broad implications with regard to the design of a new class of Li-conducting oxides based on Ruddlesden-Popper oxides.
References: [1] Selorm Joy Fanah, Ming Yu, Ashfia Huq, Farshid Ramezanipour, JMCA (DOI: 10.1039/C8TA05187A) (2018)