Ba_(0.9)Sr_(0.1)Ce_(0.9)Nd_(0.1)O_(3-α)陶瓷的离子导电性

Ionic Conduction in Ba_(0.9)Sr_(0.1)Ce_(0.9)Nd_(0.1)O_(3-α) Ceramic

用高温固相反应法制备了质子导电性陶瓷Ba0.9Sr0.1Ce0.9Nd0.1O3-α。用粉末X-射线衍射（XRD）和扫描电子显微镜（SEM）对该陶瓷材料进行了表征;用交流阻抗谱技术和气体浓差电池方法研究了材料在500~900℃温度范围内、不同气体气氛中的离子导电性,并与BaCe0.9Nd0.1O3-α和Ba0.9Ca0.1Ce0.9Nd0.1O3-α材料的导电性进行了比较。结果表明,该陶瓷材料为单一钙钛矿型BaCeO3斜方晶结构,具有良好的致密性,在高温下、CO2或水蒸气气氛中具有较高的稳定性。在湿润氢气气氛中、500~800℃温度范围内,材料的质子迁移数为1,是一个纯的质子导体;在900℃下,质子迁移数为0.964,是一个质子与电子的混合导体,质子迁移数高于BaCe0.9Nd0.1O3-α（在700~900℃温度范围内,质子迁移数为0.95）。在湿润空气气氛中,材料的质子迁移数为0.019~0.032,氧离子迁移数为0.093~0.209,是一个质子、氧离子和电子空穴的混合导体,总电导率高于Ba0.9Ca0.1Ce0.9Nd0.1O3-α。在氢-空气燃料电池条件下,材料的离子迁移数为0.957~0.903,是一个质子、氧离子和电子的混合导体,离子电导率高于Ba0.9Ca0.1Ce0.9Nd0.1O3-α。

Proton-conducting Ba0.9Sr0.1Ce0.9Nd0.1O3-α ceramic was prepared by high temperature solid state reaction.X-ray powder diffraction pattern（XRD） shows that the material is of a single orthorhombic phase of perovskite-type BaCeO3 and good stability in CO2 or water steam atmosphere at the high temperature.The SEM morphologies of the surface and the fracture of Ba0.9Sr0.1Ce0.9Nd0.1O3-α show that the material is compact.Ionic conduction of the material in different gases was studied by using ac impendence spectroscopy and gas concentration cell methods in the temperature range of 500~900 ℃,respectively,and compared with that of BaCe0.9Nd0.1O3-α or Ba0.9Ca0.1Ce0.9Nd0.1O3-α.The results indicate that the material is a pure proton conductor with the protonic transport number of 1 from 500 to 800 ℃,and a mixed conductor of proton and electron with the protonic transport number of 0.964 at 900 ℃ in wet hydrogen.The protonic transport number of Ba0.9Sr0.1Ce0.9Nd0.1O3-α in wet hydrogen is higher than that of BaCe0.9Nd0.1O3-α（0.95,from 700 to 900 ℃）.In wet air,the material is a mixed conductor of proton,oxide ion and electronic hole with the protonic transport numbers of 0.019~0.032 and the oxide ionic transport numbers of 0.093~0.209.In hydrogen-air fuel cell,the material is a mixed conductor of proton,oxide ion and electron with the ionic transport numbers of 0.957~0.903.Under the same conditions,Ba0.9Sr0.1Ce0.9Nd0.1O3-α has higher total conductivity in wet air and ionic conductivity in hydrogen-air fuel cell than Ba0.9Ca0.1Ce0.9Nd0.1O3-α.