The effects of counter cation on lithium ion conductivity: In the case of the perovskite-type titanium oxides of La2/3 − x Li3xTiO3 and LaTiO3

We performed hybrid-DFT calculations for La2/3 − xLi3xTiO3 (LLT) with lithium ion conductivity, in order to investigate the detailed lithium ion conductive mechanism from the viewpoint of molecular orbital (MO) method. It was concluded that the very ionic lithium ion in bottleneck accelerates the lithium ion conduction. The calculated MO shows no chemical bonding between lithium ion and other ions. In comparison with the perovskite-type trivalent titanium oxide of LaTiO3, the effect of the titanium's reduction was also investigated. We showed the possibility of the high lithium conductivity in LaTiO3.