新型ITSOFC阴极材料Ln_(0.7)Sr_(0.3)CoO_(3-δ)的合成与电性能研究

Research on synthesis and electrical properties of the new Ln_(0.7)Sr_(0.3)CoO_(3-δ) cathode materials ITSOFC

为降低制备阴极材料的成本、促进中温固体氧化物燃料电池(ITSOFC)的工业化进程,采用混合稀土作为主要原料,外加SrCO3、Co2O3固相法制备了Ln0.7Sr0.3CoO3-δ(简:LnSC,Ln为混合稀土)复合氧化物。TG-DSC、XRD对LnSC材料的合成过程以及不同温度下烧结行为进行了研究,并考察了LnSC材料的电性能。结果表明:混合稀土促进了SrCO3在700～950℃的分解反应,同时在1100℃时新相Ln0.7Sr0.3CoO3-δ基本形成。1200℃烧结4h后合成产物为CeO2立方萤石相与钙钛矿相的共存。该材料电导率在340℃时达到最大值638S/cm,500～800℃时,电导率超过500S/cm,其电导活化能为7.86kJ/mol,满足ITSOFC对阴极材料的要求。

In order to reduce the cost of cathode materials and accelerate the industrialization course of intermediate temperature solid oxide fuel cells（ITSOFC）, the cathode materials of Ln0.7Sr0.3CoO3-δ（LnSC, Ln is mixed rare earth） were synthesized by solid state reaction method using the lower cost mixed rare earth and others SrCO3, Co2O3 as raw materials. The effects of calcined temperature on the phase structure were investigated by TG-DSC and XRD. The experimental results show that the strontium carbonate powers accelerate decomposing action at the range of 700-950℃ and the new phase is formed completely at 1 100 ℃. LnSC is two phase with cubic fluorite and perovskite sinterad at 1 200 ℃for 4 h. The electrical conductivity of samples increases with temperature up to 340 ℃and the maximum is 638 S/cm, and higher than 500 S/cm from 500℃ to 800 ℃. The calculated activation energy of electrical conductivity get to 7.86 kJ/mol, it can meet the need of cathode for ITSOFC.