碱土金属双掺杂铁钴酸镧的制备和表征

柠檬酸法制备了La0.7Ba0.15E0.15Fe0.8Co0.2O3(LBEFC,E=Sr,Ca)系列阴极材料,利用XRD、SEM对LBEFC晶体结构、微观形貌进行分析,采用四探针法测试了LBEFC的电导率。实验结果表明,1 000℃煅烧2 h,LBEFC可以形成单一的畸变钙钛矿结构,LBEFC衍射峰较LaFeO3衍射峰向右偏移,晶胞参数a、b减小,c增大。La0.7Ba0.15Sr0.15Fe0.8Co0.2O3和La0.7Ba0.15Ca0.15Fe0.8Co0.2O3晶胞体积膨胀率分别为43.5%、42.7%,晶格畸变主要发生在(200)、(211)晶面方向。在300~800℃,LBEFC电导率均大于100 S/cm,满足中温固体氧化物燃料电池阴极材料的要求。LBEFC与新型电解质Ce0.8Sm0.2O2在1 200℃下烧结5 h,没有新相生成,具有良好的相容性。

Preparation and characterization of alkaline earth metal mixed with lanthanum iron oxide

The crystal structure,micro-appearance of the cathode materials La0.7Ba0.15E0.15Fe0.8Co0.2O3(LBEFC,E=Sr,Ca) made by citrate method were analyzed by XRD,SEM.Its electrical conductivities were determined by four probes method.The results showed that LBEFC formed a expansible lattice distortion perovskite structure atter calcined at 1 000 ℃ for 2 h.Compared with LaFeO3,the diffraction peaks of La0.7Sr0.2Ca0.1Fe0.8Co0.2O3 were shifted to the right and the lattice parameters a,b were decreased,c was increased.La0.7Ba0.15Sr0.15Fe0.8Co0.2O3 and La0.7Ba0.15Ca0.15Fe0.8Co0.2O3 cell volume expansion ratio were 43.5%,42.7% respectively.The lattice distortion occurs mainly in the(200),(211) crystal plane orientation.The electrical conductivity of LBEFC is more than 100 S/cm from 300 ℃ to 800 ℃ and it could satisfy the requirement of intermediate temperature Solid Oxide Fuel Cell.When the mixed powders sintered at 1 200 ℃ for 5 h between Ce0.8Sm0.2O2 electrolyte and LBEFC have good chemical compatibility.