Characteristic fast H- ion conduction in oxygen-substituted lanthanum hydride
Characteristic fast H- ion conduction in oxygen-substituted lanthanum hydride
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DOI：
10.1038/s41467-019-10492-7
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发表时间：
2019-06-12
影响因子：
16.6
通讯作者：
Hosono, Hideo
中科院分区：
文献类型：
--
作者：
Fukui, Keiga;Iimura, Soshi;Hosono, Hideo
快速离子导体在能量存储和转换技术的发展方面具有巨大的潜力。氢化物（H-）离子是一种独特的离子，因为它们的天然丰度、轻质量和大极化率。在此，我们研究了H-传导的特征，即由指数前因子控制的快速离子传导。氧掺杂的LaH3 （LaH3- 2xox）具有2.6 x10(-2) S cm（-1）的最佳离子电导率，据我们所知，这是迄今为止在中等温度下报道的最高H电导率。随着氧含量的增加，相对较高的活化能保持不变，而指前因子急剧下降。这个异常大的指数前因子是通过引入温度依赖的焓来解释的，焓来自于镧离子与氧离子结合所捕获的H。因此，la3 - 2xox中H-的轻质量和大极化率以及由高密度H-组成的框架是使势能具有显著温度依赖性和实现特征快速H传导的关键因素。
Fast ionic conductors have considerable potential to enable technological development for energy storage and conversion. Hydride (H-) ions are a unique species because of their natural abundance, light mass, and large polarizability. Herein, we investigate characteristic H- conduction, i.e., fast ionic conduction controlled by a pre-exponential factor. Oxygen-doped LaH3 (LaH3-2xOx) has an optimum ionic conductivity of 2.6 x10(-2) S cm(-1), which to the best of our knowledge is the highest H- conductivity reported to date at intermediate temperatures. With increasing oxygen content, the relatively high activation energy remains unchanged, whereas the pre-exponential factor decreases dramatically. This extraordinarily large pre-exponential factor is explained by introducing temperature-dependent enthalpy, derived from H- trapped by lanthanum ions bonded to oxygen ions. Consequently, light mass and large polarizability of H-, and the framework comprising densely packed H- in LaH3-2xOx are crucial factors that impose significant temperature dependence on the potential energy and implement characteristic fast H- conduction.