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.

质子传导是燃料电池电解质的重要特性。寻找有关质子传输的分子细节是一个持续的追求。在这里，我们显示在X射线和中子衍射中，在水合钇掺杂的锆酸钡中，质子倾向于以共轭超结构的形式位于掺杂钇附近。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OH拉伸运动弱耦合，而与低频晶格声子强耦合。质子极化子有效质量m ^*与质子质量之比为m ^* / m = 2，当与Zr-O拉伸模式耦合时，由于质子-声子耦合，提供了钙钛矿中质子配对的实验证据。通过轻推弹性带计算可提供质子对的可能途径。质子在跳跃时的配对是在协作质子电荷传输过程的背景下讨论的。