Cooperative origin of proton pair diffusivity in yttrium substituted barium zirconate
Cooperative origin of proton pair diffusivity in yttrium substituted barium zirconate
复制标题
钇取代的锆酸钡中质子对扩散率的合作起源（开放获取）
DOI：
10.1038/s42005-020-00464-5
复制
发表时间：
2020-11-04
影响因子：
5.5
通讯作者：
Braun, Artur
中科院分区：
文献类型：
--
作者：
Du, Peng;Chen, Qianli;Braun, Artur
质子传导是燃料电池电解质的重要特性。寻找质子传输的分子细节是一项持续的探索。在这里，我们使用 X 射线和中子衍射表明，在水合钇掺杂锆酸钡中，质子倾向于定位在掺杂剂钇附近作为共轭超结构。使用准弹性中子散射测量的质子跳跃时间遵循 Holstein-Samgin 极化子模型，表明质子跳跃与高频 O-H 伸缩运动弱耦合，但与低频晶格声子强耦合。当与 Zr-O 拉伸模式耦合时，质子极化子有效质量 m(*) 与质子质量之比为 m(*)/m = 2，作为质子-声子耦合的结果，给出了钙钛矿中质子配对的实验证据。通过微移弹性带计算提供了质子对的可能路径。在合作质子电荷传输过程的背景下讨论了跳跃时的质子配对。通过陶瓷电解质膜的质子传导涉及 H+ 离子通过晶格的离子传输。在这里，作者研究了潜在的分子输运机制，并证明掺钇锆酸钡中的质子传导是通过协作质子运动发生的。
Proton conduction is an important property for fuel cell electrolytes. The search for molecular details on proton transport is an ongoing quest. Here, we show that in hydrated yttrium doped barium zirconate using X-ray and neutron diffraction that protons tend to localize near the dopant yttrium as a conjugated superstructure. The proton jump time measured using quasi-elastic neutron scattering follows the Holstein-Samgin polaron model, revealing that proton hopping is weakly coupled to the high-frequency O-H stretching motion, but strongly coupled to low-frequency lattice phonons. The ratio of the proton polaron effective mass, m(*), and the proton mass is m(*)/m = 2, when coupled to the Zr-O stretching mode, giving experimental evidence of proton pairing in perovskites, as a result of proton-phonon coupling. Possible pathways of a proton pair are provided through Nudge Elastic Band calculations. The pairing of protons, when jumping, is discussed in context of a cooperative protonic charge transport process. Proton conduction through ceramic electrolyte membranes involves the ionic transport of H+ ions through a crystalline lattice. Here, the authors investigate the underlying molecular transport mechanism and demonstrate that proton conduction in yttrium-doped barium zirconate occurs through cooperative proton motion.