层状无机质子导体ABO3中缺陷态结构对质子导电性能的影响研究

High temperature inorganic proton conductor has great potential on hydrogen isotope purification, however, the low proton conductivity and the unclear proton transfer mechanism limit the application of these materials on the hydrogen isotope separation. In this work, the high temperature inorganic proton conductor which has layered perovskite structure is used as matrix material. The suitable proton transfer channel is established by introducing appropriate defects center (positive, negative and neutral defects) which can alter the layered structure of materials. The variability of layered perovskite structure is beneficial to the formation of defect and the changing of crystal structure. In order to realize the modulation of the microstructure and the proton transfer kinetics, the different types defects (such as positive, negative, neutral and cluster of defects) are regulated to changing the layered structure of materials in this research. Furthermore, a comprehensive understanding of the intrinsic properties of defects and proton captured process will be proposed, based on the investigation of micstructure of defects. The First Principle calculation methode is used to make sure the role of the defect for the crystal structure, the trapping process of.proton, the release of the proton and transfer process, so as to establish proton transfer mechanism model.The results are of importance to not only for designing and developing the high temperature inorganic proton conductor with high proton conductivity, but also for understanding the mechanism of the proton transfer.

高温无机质子导体在氢同位素分离上有着巨大的应用潜力，然而由于其质子导电性低，质子传递机理不清限制了该种材料的应用。本项目拟选择具有层状钙钛矿结构的基质材料，通过引入具有合适能级结构缺陷中心（正电、负电及电中性缺陷），改变材料的层状结构，构建合适的质子传递通道。层状钙钛矿结构的多变性，为缺陷态的形成及晶体结构的改变提供条件。项目以调控正电性、负电性、电中性缺陷及缺陷缔合体为切入点，对层状结构进行设计，实现缺陷结构变化对微观结构以及质子传递动力学过程进行调制。通过微观缺陷结构的研究，探究缺陷态的本征属性及其俘获质子的能力，通过第一性原理计算，进一步了解缺陷态的引入对材料晶体结构的改变，及质子俘获、释放及运输的物理机制，构建质子传递机理模型。项目的研究成果将为氢同位素分利用高质子导电性的无机质子导体材料的设计和研发提供新的思路和理论依据。

核能是一种新型能源，其开发和利用对氢同位素分离和纯化提出了迫切要求。BaZrO3基钙钛矿氧化物是一种有效分离纯化氢同位素的材料。但BaZrO3基化合物存在合成温度高、保温时间长、质子导电性极低、质子导电机理尚不明确等问题。鉴于此，拟通过掺入助熔剂降低该材料的烧结温度及缩短保温时间，并在BaZrO3基质内部构建不同的缺陷态，采用发射光谱和热释光谱相结合研究缺陷态对材料质子导电性能的影响。.利用高温固相法制备BaZr1-xYxO3-δ（0≦x≦0.3）系列样品；通过XRD测试表明Y的最大掺量为24mol%；随着Y的掺杂浓度增加电导率增加（x≦0.2），同时由于测试掺Y含量22mol%、24mol%的电导率都尚未超过20mol%的电导率；通过采用Y的不等价取代会形成缺陷，采用发射光谱与热释光谱分析表明不等价取代形成了氧空位氧空位有利于质子传导；Y掺入BaZrO3晶格中会形成新的负电荷中心 可俘获晶体中传导的质子使得晶体中的有效质子浓度降低,缺陷含量随着Y掺入量增加而增加，缺陷陷阱深度变浅降低了对质子俘获的能力或者增加了对俘获质子的释放能力，从而使导电性提高。.采用电荷补偿剂可以有效的改善材料的质子导电型。其中掺LiOH和NaOH能显著提高质子导电性，而掺入LiCl和NaCl导致质子导电性略有降低。采用发射光谱与热释光谱相结合的手段分析，发现掺LiOH和NaOH样品的热释光谱的T1峰和发射光谱峰的P1峰均显著降低，以及缺陷浓度减小，有利于降低对质子的俘获数量；且热释峰的T1峰向低温方向移动，缺陷陷阱变浅导致俘获质子的能力降低；