Proton conducting mechanism in perovskite metal oxides from viewpoints of local structural relaxation and local chemical bonding change

Abstract

From our previous molecular orbital calculations using hybrid density functional theory for proton-conducting perovskite metal oxides, it was found that proton pumping effect is combined during proton-conduction, and covalent bonding change occurs in a diagonal line. It is known that pure perovskite metal oxides are regarded as boundary system. It is because they consist of the same unit structures. However, during proton-conduction, both local structural relaxation and local chemical bonding change must be taken into consideration. In this paper, the proton-conducting mechanism is explained from the different viewpoints of local structural relaxation and local chemical bonding change.From our previous molecular orbital calculations using hybrid density functional theory for proton-conducting perovskite metal oxides, it was found that proton pumping effect is combined during proton-conduction, and covalent bonding change occurs in a diagonal line. It is known that pure perovskite metal oxides are regarded as boundary system. It is because they consist of the same unit structures. However, during proton-conduction, both local structural relaxation and local chemical bonding change must be taken into consideration. In this paper, the proton-conducting mechanism is explained from the different viewpoints of local structural relaxation and local chemical bonding change.