Dynamics of Anisotropic Oxygen-Ion Migration in Strained Cobaltites
Dynamics of Anisotropic Oxygen-Ion Migration in Strained Cobaltites
复制标题
应变钴矿中各向异性氧离子迁移动力学
DOI：
10.1021/acs.nanolett.1c04057
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发表时间：
2021
期刊：
影响因子：
10.8
通讯作者：
Er-Jia Guo
中科院分区：
文献类型：
--
作者：
Qinghua Zhang;Fanqi Meng;Ang Gao;Xinyan Li;Qiao Jin;Shan Lin;Shengru Chen;Tongtong Shang;Xing Zhang;Haizhong Guo;Can Wang;Kuijuan Jin;Xuefeng Wang;Dong Su;Lin Gu;Er-Jia Guo
氧空位通道（OVC）的方向控制对于定制氧扩散非常有用，因为它充当离子导体中的快速传输通道，广泛应用于固态燃料电池、催化剂和离子电池。直接观察氧离子向优先空位的跳跃是阐明迁移途径的关键。在这里，我们报告了在原子分辨透射电子显微镜中通过原位热激活由超薄钴矿中的应变介导的各向异性氧离子迁移。氧迁移路径是根据OVC转换过程中的原子结构构建的，表现为拉伸应变下OVC从垂直到水平的转换，以及压缩下水平到对角线的转换。我们评估了 OVC 的拓扑结构变化，确定了耐受因子对 OVC 稳定性的关键作用，并建立了应变相关相图。我们的工作为适用于离子氧化物电子器件的 OVC 方向工程提供了实用指南。
Orientation control of the oxygen vacancy channel (OVC) is highly desirable for tailoring oxygen diffusion as it serves as a fast transport channel in ion conductors, which is widely exploited in solid-state fuel cells, catalysts, and ion-batteries. Direct observation of oxygen-ion hopping toward preferential vacant sites is a key to clarifying migration pathways. Here we report anisotropic oxygen-ion migration mediated by strain in ultrathin cobaltites viain situthermal activation in atomic-resolved transmission electron microscopy. Oxygen migration pathways are constructed on the basis of the atomic structure during the OVC switching, which is manifested as the vertical-to-horizontal OVC switching under tensile strain but the horizontal-to-diagonal switching under compression. We evaluate the topotactic structural changes to the OVC, determine the crucial role of the tolerance factor for OVC stability, and establish the strain-dependent phase diagram. Our work provides a practical guide for engineering OVC orientation that is applicable to ionic-oxide electronics.