新型电解质材料La_(1.94)Sr_(0.06)Mo_2O_(9-δ)的制备与性能  

Synthesis and Properties of a Novel Electrolyte Material La_(1.94)Sr_(0.06)Mo_2O_(9-δ)

作　　者：高喜梅[1] 周青军[2] 

机构地区：[1]上海应用技术学院理学院,上海201418 [2]中国民航大学理学院,天津300300

出　　处：《四川师范大学学报（自然科学版）》2015年第1期95-100,共6页Journal of Sichuan Normal University（Natural Science）

基　　金：上海高校选拔培养优秀青年教师科研专项基金(YYY10076)资助项目

摘　　要：氧离子导体La2Mo2O9在580℃左右存在低温α相向高温β相的结构相变,这是影响其成为固体氧化物燃料电池(SOFC)电解质材料的关键因素.采用以EDTA为主要络合剂的溶胶-凝胶法合成电解质材料La1.94Sr0.06Mo2O9-δ粉体,利用X射线衍射(XRD)仪、扫描电子显微镜(SEM)分别观察样品的微观结构和表面形貌,用热膨胀仪分析样品的热学性质,通过电导率的测量分析样品电学性质,并和传统固相法制得的同掺杂量的样品进行比较,结果表明溶胶-凝胶法制得的样品在600℃烧结8 h便可形成高电导率的高温立方相,成相温度有所降低,并且可以稳定到室温;同时晶粒尺寸明显减小,平均晶粒尺寸在500 nm左右,低温电导率有了很大的提高,550℃时σ=0.006 S/cm,中温800℃时σ=0.12 S/cm.既有效地抑制La2Mo2O9的结构相变,又提高该氧离子导体的中低温离子电导率,可以降低电池的操作温度.The ion conductor La2Mo2O9 undergoes a reversible phase transition from high-temperature β-phase to low-temperatureα-phase at 580 ℃. This phase transition greatly limits the potential application of La2Mo2O9 as a solid electrolyte material of Solid Oxide Fuel Cell（ SOFC）. A novel electrolyte material La1. 94Sr0. 06Mo2O9-δwas prepared by an EDTA / citrate complex sol-gel method.The microstructure and surface topography were characterized by X-ray diffraction and scanning electron microscope,respectively. The cubic β-phase was formed and stabilized by sintering at about 600 ℃. Both the phase formation temperature and the grain size decreased compared to that prepared by the solid state reaction. The dense pellet with an average grain size of 500 nm was obtained when the sample was sintered at 800 ℃ for 8 h,which was confirmed through thermal expansion and electrical conductivity measurements.The electrical conductivity was measured by measuring the DC resistant,and the value is as high as 0. 006 S / cm at 550 ℃ and0. 12 S / cm at 800 ℃. At lower working temperature,the phase transition of La2Mo2O9 is suppressed and the ion conductivity is increased.

关 键 词：电解质材料 溶胶-凝胶 La2Mo2O9 微观结构 离子电导率 

分 类 号：O646.5[理学—物理化学]