Preparation of solid electrolyte nano-sized powders and examination of relationship between oxide tonic conductivity and nano- structural features in sintered bodies

为了设计高质量的掺杂CeO_2固体电解质，必须使样品的氧化物电导率最大化，并使n型半导体性质最小化。为了实现这些目标，我们在原子尺度上观察了微观结构。研究了掺杂CeO_2烧结体的电导率与显微结构的关系。本研究制备了20种电解质（Sm_xCe_<1-x>O_&lt;2-x/2&gt;和Gd_xCe_<1-x>O_&lt;2-x/2&gt;，x=0.05，0.1，0.15，0.2和0.25）和n型半导体（Ho_xCe_<1-x>O_&lt;2-x/2&gt;和Tb_xCe_ O_<1-x>&lt;2-x/2&gt;，x=0.05，0.1，0.15，0.2和0.25）样品，研究了烧结体的物理性能（如电导率、活化能等）与烧结体纳米结构特征之间的关系。碳酸盐共沉淀法制备的粉体平均粒径约为3 nm。对上述标本进行了组织学观察， 关于我们 强化95%以上的理论密度。使用直流测量方法测量烧结体中的电导率。利用透射电子显微镜（TEM）在原子尺度上进行微观结构特征的观察。在电解质Sm_xCeCe_<1-x>O_&lt;2-x/2&gt;和Gd_xCe_<1-x>O_&lt;2-x/2&gt;中观察到具有有序氧空位结构的微畴。随着微畴含量和尺寸的增加，烧结体的电导率降低。而在Ho_xCe_<1-x>O_&lt;2-x/2&gt;和Tb_xCe_<1-x>O_&lt;2-x/2&gt;烧结体中观察到了细小的析出相。在沉淀物中观察到大量的Ce^&lt;3+&gt;和dopant阳离子。在Ho_xCe_<1-x>O_（2-x/2）和Tb_xCe_<1-x>O_（2-x/2）烧结体中，观察到典型的n型半导体特性。因此，为了设计高质量的掺杂CeO_2固体电解质，必须使掺杂CeO_2烧结体中的微畴尺寸最小化，并去除掺杂CeO_2烧结体中的沉淀物。少

For a design of high quality doped CeO_2 solid electrolytes, the oxide tonic conductivity must be maximized and the n-type semi-conducting property must be minimized into the specimens. In order to achieve them, we observed the micro-structure at atomic scale. Also we examined the relationship between electrical conductivity and micro-structural features in the doped CeO_2 sintered bodies. In the present study, we prepared the 20 kinds of specimens which are the electrolytes (Sm_xCe_<1-x>O_<2-x/2> and Gd_xCe_<1-x>O_<2-x/2>, x=0.05, 0.1, 0.15, 0.2 and 0.25) and n-type semi-conductors (Ho_xCe_<1-x>O_<2-x/2> and Tb_xCe_<1-x>O_<2-x/2>, x=0.05, 0.1, 0.15, 0.2 and 0.25) to examine the relationship between physical properties (i.e. electrical conductivity, activation energy, and so on) of sintered bodies and nano-structural features in sintered bodies. The average particle size of powders prepared by carbonate co-precipitation method was approximately sonm. The aforementioned specimens were d … More ensified more than 95 % of theoretical density. The conductivity in the sintered bodies was measured using direct current measurement method. The observation of micro-structural features at atomic scale was performed using transmission electron microscopy (TEM). The micro-domains with ordered structure of oxygen vacancy were observed in the electrolytes (i.e. Sm_xCeCe_<1-x>O_<2-x/2> and Gd_xCe_<1-x>O_<2-x/2>. The conductivity in those sintered bodies was decreased with increasing micro-domain content and micro-domain size. On the other hand, the small precipitates were observed in Ho_xCe_<1-x>O_<2-x/2> and Tb_xCe_<1-x>O_<2-x/2> sintered bodies. The huge amount of Ce^<3+> and do pant cation was observed into the precipitates. In the case of Ho_xCe_<1-x>O_<2-x/2> and Tb_xCe_<1-x>O_<2-x/2> sintered bodies, the typical n-type semi-conducting property was observed. Accordingly, for a design of high quality doped CeO_2 solid electrolytes, it is concluded that the micro-domain size must be minimized in the doped CeO_2 sintered bodies and the precipitates must be removed from the doped CeO_2 sintered bodies. Less