La1-xSrxYO3-α陶瓷的合成及电性能研究

Synthesis and Electrical Properties of La_(1-x)Sr_xYO_(3-α)Ceramics

本文采用高温固相法合成了La1-xSrxYO3-α(x=0.00,0.05,0.10,0.15)系列陶瓷样品,用XRD、SEM对样品进行了表征,并用交流阻抗谱、氢泵、氢浓差电池、氧浓差电池等系统地研究了该系列样品的电性能。结果表明,该系列陶瓷样品均为钙钛矿型单斜晶相结构;样品的氢浓差电池电动势的实测值和理论值吻合得很好,表明样品在氢气气氛中为纯离子导体;氢泵测试结果证实了样品在氢气气氛中基本上是质子导体;氧分压与电导率的关系表明样品在高氧分压气氛中是离子(质子+氧离子)和空穴的混合导体,在低氧分压气氛中是离子(质子+氧离子)导体;氧浓差电池测试结果表明样品在干燥的氧化性气氛中是氧离子和空穴的混合导体。

The ceramic samples of La1-xSrxYO3-α（x=0.00, 0.05, 0.10, 0.15） were prepared using a conventional solid state reaction method and characterized by XRD, SEM. The electrical properties of La1-xSrxYO3-α ceramics were investigated by means of various electrochemical methods, e.g. ac impedance spectroscopy, hydrogen pumping, gas concentration cells including hydrogen concentration cell and oxygen concentration cell etc. X-ray powder diffraction pattern showed that the structures were all monoelinic perovskite. The observed values of hydrogen concentration cell coincided with theoretical ones perfectly, indicating that the ceramics were pure ionic conductors under hydrogen atmosphere. The results of hydrogen pumping confirmed that the ceramics mainly were proton conductors under hydrogen atmosphere. The dependence of conductivity on oxygen partial pressure revealed that the samples were mixed conductors of ions （H^＋＋O2-） and hole at high oxygen partial pressure, but were pure ionic （H^＋＋O2-） conductors at low oxygen partial pressure. The results of oxygen concentration cell exhibited that the samples were mixed conductors of oxide-ion and hole in dry oxidizing atmospheres.