钴掺杂Sr1.5La0.5MnO4的合成及高温电化学性能研究

Synthesis and High Temperature Electrochemical Properties of Co-doped Sr_(1.5)La_(0.5)MnO_4

采用EDTA-柠檬酸法合成了中温固体氧化物燃料电池阴极材料Sr_(1.5)La_(0.5)Mn_(1-x)Co_xO_4(SLMCOx),并利用粉末X射线衍射(XRD)、X射线光电子能谱(XPS)以及电化学交流阻抗谱(EIS)进行表征。结果表明,该材料与Ce0.9Gd0.1O1.95(CGO)在1 200℃烧结12 h不发生化学反应。随着Co掺入量的增加,氧化物中Mn^(3+)和Co^(2+)含量增多,晶格氧含量降低,晶格畸变率增大。交流阻抗谱(EIS)测试结果显示,钴的掺杂明显降低电极的极化电阻,其中Sr_(1.5)La_(0.5)Mn_(0.7)Co_(0.3)O_4阴极在700℃空气中的极化电阻为0.62Ω·cm^2,明显小于Sr_(1.5)La_(0.5)MnO_4阴极在750℃的极化电阻(1.5Ω·cm^2),表明钴掺杂的Sr_(1.5)La_(0.5)Mn_(1-x)CoxO_4是一种潜在的IT-SOFC阴极材料。

Sr1.5La0.5Mn1-xCoxO4 （SLMCOx） cathode materials for IT-SOFCs （intermediate temperature solid oxide fuel cells） were synthesized by EDTA-citric acid method and characterized by XRD, XPS and EIS, respectively. The results show that SLMCOx has no reaction with Ce0.9Gd0.1O1.95 at 1 200℃ for 12 h. Both the amount of Mn3 and Co2 in the oxide increase with the Co doping concentration; at the same time the content of lattice oxygen reduces, and the distortion ratio （c/a） of the lattice increases. The EIS results show that Co-doping dramatically reduces the polarization resistance （Rp） of SLMCOx cathode. The Sr1.5La0.5Mn0.7Co0.3O4 has the lowest Rp of 0.62 Ωcm2 at 700℃ in air, which is clearly smaller than the Rp value of Sr1.5La0.5Mn0.7O4 that measured at 750℃ （1.5 Ωcm2）. Our results indicate that the Co doped Sr1.5La0.5Mn1-xCoxO4 is potential cathode material for IT-SOFC.