Changes in electronic structure upon lithium insertion reaction into the A-site deficient perovskite type oxides, Gd1/3TaO3: Part 2. Ab initio calculation

In this paper, the second of a two-part paper, results obtained by ab anitio calculation for the investigation on the electronic structure of electrochemically lithiated perovskite oxides LixGd1/3TaO3 are presented. From the results of ab initio calculation based on density functional theory, it was confirmed that tantalum and oxygen formed a covalent bond, while the electronic orbital gadolinium and lithium are localized and showed an ionic character. Comparison of the electronic structure between before and after lithium insertion indicated that Ta reduced its oxidation state from Ta5+ to Ta4+. The detailed analysis of electronic distribution in the lattice revealed that the electron transfer also occurs around oxide ion, especially between lithium and oxygen.