Strain‐induced tunable energy barrier of proton diffusion in Y‐doped BaCeO3 and Y‐doped BaZrO3. (23rd January 2022)

• Record Type: Journal Article
• Authors: Niu, Hongwei; Jing, Yuhang; Sun, Yi; Guo, Licheng; Aluru, Narayana R.; Li, Weiqi; Yang, Jianqun; Li, Xingji
• Is Part Of: International journal of energy research. Volume 46:Number 6(2022)
• Page Start: 7816
• Page End: 7824
• Publication Date: 2022-01-23
• Subjects: density functional theory -- energy barrier -- perovskite oxide -- proton diffusion -- strain effect; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Power resources -- Research -- Periodicals; 621.042
• DOI: 10.1002/er.7682
• Languages: English
• ISSNs: 0363-907X

Abstract

Summary: In this paper, the strain effects on the energy barrier of proton diffusion in Y‐doped BaCeO3 (BCY) and Y‐doped BaZrO3 (BZY) are investigated by detailed density functional theory calculations. The energy barrier of proton rotation decreases when the tensile strain is applied. For intra‐octahedral proton transfer, the energy barrier decreases when the tensile strain is applied while for inter‐octahedral proton transfer the energy barrier increases when the tensile strain is applied. However, we found that for intra‐octahedral proton transfer the energy barrier of BZY shows the opposite strain effect. To understand the underlying mechanism behind this opposite trend we decomposed proton diffusion into three elementary steps and the opposite trend of the energy barrier of BCY and BZY during intra‐octahedral proton transfer is pinpointed to the opposite bond order change of the hydrogen bond. In all, we explored the strain effects on the energy barrier of proton diffusion in BCY and BZY from a microscopic perspective, showing the potential to tune the energy barrier of proton transport in perovskite oxide with strain engineering and thus design novel proton conductors. Abstract : We extend the investigation of the strain effect of the proton diffusion energy barrier to Y‐doped BaCeO3 (BCY) and Y‐doped BaZrO3 (BZY), which manifest excellent proton conductivity. Proton diffusion in BCY was decomposed to a three elementary steps mechanism to provide a microscopic picture of the process. The different strain effect of the proton diffusion energy barrier of BCY and BZY during intra‐octahedral proton transfer is attributed to the bond order changes of the hydrogen bond during the elementary steps.