La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.2)O_(3-α)陶瓷的质子导电性能研究

Study on Proton Conduction in La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.2)O_(3-α) Ceramics

采用溶胶-凝胶法合成了La0.8Sr0.2Ga0.8Mg0.2O3-α陶瓷样品,用XRD,DSC-TGA,SEM,交流阻抗谱,气体浓差电池及气体电化学透过等方法对样品的结构和性质进行了表征和测试.首次对该样品的质子导电性能进行了研究.该陶瓷样品具有良好的微观结构,相对密度达95.1%;氢浓差电池电动势的实测值与理论值吻合,离子迁移数为1;在干燥的氧气气氛中是一个纯的氧离子导体;氢的电化学透过速率的实测值与理论值吻合,证明该样品在氢气气氛中几乎是一个纯的质子导体,质子电导率在1000℃时高达0.14S·cm-1.

The La0.8Sr0.2Ga0.8Mg0.2O3-α ceramics was synthesized via a sol-gel method. The structure and properties were determined and characterized through XRD, DSC-TGA, SEM and AC impedance spectroscopy, gas concentration cell and gas electrochemical permeation （pumping） methods. The proton conduction behavior was studied by using electrochemical methods for the first time. The compact ceramics had a good microstructure, and the relative density was 95.1%. The experimental values of the hydrogen concentration cell coincided well with the theoretical ones, and the ionic transport number was unity. It is a pure oxide ionic conductor in a dry oxygen atmosphere. The observed rate of electrochemical hydrogen permeation was close to the theoretical rate, verifying that the ceramics was almost a pure proton conductor and the proton conductivity was 0.14 S·cm^-1 at 1000℃ under a hydrogen atmosphere.