Quantum Chemistry in Nanoscale-Hydride Ion Conducting Perovskites


Taku Onishi


Graduate School of Engineering, Mie University, JAPAN



Abstract:

Hydride ion, which has negative charge, has attracted much scientific interest from the viewpoint of fast ion conduction. Recently, several hydride ion conducting inorganics have been reported: BaTiO3 perovskite, La2LiHO3 perovskite and so on. Form our molecular orbital analysis using chemical bonding rule, it was found that the ion conducting mechanism is different from proton conducting one. For example, in BaTiO3 perovskite, it was discovered that covalent bonding is formed between hydrogen anion and other atoms, and fluctuation of hydrogen anion can be caused. Further, the smaller activation energy was obtained, in comparison with proton conducting perovskites. In this presentation, new hydride ion conducting perovskites such as KMgH3 and hydride ion doped KMgF3 perovskites are focused on. It was found that the hydride ion conduction is combined with “competitive fluctuation”. It implies that fluorine anion also migrates around local minimum during hydride ion conduction. In this lecture, the detailed mechanism is clearly explained, and finally the safety is also discussed. Reference (1)Taku Onishi, Chapter 2: Quantum Chemistry in Perovskite Fluoride and Hydride: Nanoscale Hydride Ion Conduction, “Theoretical Chemistry for Advanced Nanomaterials-Functional Analysis by Computation and Experiment” (2020, Springer Nature)