摘要
具有通式A2B′(B2O7)的层状黄长石结构是由交替的A2大阳离子层和B′(B2O7)四面体层构成。当A位离子为混合的稀土金属元素和碱土金属元素时, B′和B位离子可为同种三价元素离子,比如铝或镓。在B′(B2O7)四面体层中,四面体呈(3, 4)连接从而沿着层堆积方向形成五元环通道。而夹在相邻四面体层中间的A位大阳离子处于五元环通道的八配位环境中。这种特殊的层状结构中不同位置上的阳离子在发生不等价取代或者被氧化时,结构中可以引入一定量的缺陷从而引起局域结构的变化和物理性能的改变。2008年,黄长石镓酸盐材料被发现其稀土离子对碱土金属离子的取代可以引入具有高迁移能力的间隙氧缺陷,在中低温固态氧化物燃料电池电解质材料上呈现了潜在的应用价值,因此具有黄长石型结构的材料及其离子导电性质受到越来越多的关注。总结了自2008年以来基于黄长石结构的氧离子导体在新材料制备、缺陷稳定和迁移机制等方面的研究工作进展。
The layered melilite structure having the general formula A2B′(B2O7) is composed of alternating A2 large cationic layers and B′(B2O7) tetrahedral layers. When mixed rare earth metal element and an alkaline earth metal element occupy A sites, the B′ and B ions may be the same trivalent element ion such as aluminum or gallium. In the B′(B2O7) tetrahedral layer, the tetrahedron is(3,4) linked to form pentagonal tunnels along the stacking direction. The A-site large cation sandwiched between adjacent tetrahedral layers is in the eight-coordinate environment of the pentagonal tunnels.Under aliovalent substitution or oxidation on the cation sites, a certain number of defects can be introduced in the structure to cause changes in the local structure and physical properties. In 2008, it was found that the substitution of rare earth ions for alkaline earth metal ions in melilite gallate materials can introduce interstitial oxygen defects with high mobility, which has potential application in electrolyte materials of low and medium temperature solid oxide fuel cells. Therefore, materials with melilite structure and ionic conductivity have attracted more and more attention. This paper summarizes the research progress on new material preparation, defect stabilization and migration mechanism of oxygen ion conductors based on melilite structure since 2008.
作者
周立佳
耿仕鹏
尹从岭
匡小军
Zhou Lijia;Geng Shipeng;Yin Conglin;Kuang Xiaojun(College of Materials Science and Engineering,Guilin University of Technology,Guilin 541004,China)
出处
《中国稀土学报》
CAS
CSCD
北大核心
2020年第3期345-358,I0002,共15页
Journal of the Chinese Society of Rare Earths
基金
国家自然科学基金项目(21622101)资助。
关键词
黄长石结构
氧离子导体
缺陷工程
四面体
稀土
melilite structure
oxygen ion conductor
defect engineering
tetrahedron
rare earths
