阴极材料Ln-Sr(orCa)-Cu-O的制备及电性能

为了降低原料成本和适于工业化生产,以混合稀土取代氧化镧经硝酸溶解后,共沉淀法分别制备了Sr、Ca掺杂阴极材料Ln-Sr(or Ca)-Cu-O(Ln为混合稀土)的前驱体,在优化条件800℃下煅烧3.5 h形成了粉体,XRD证实形成的物相为CeO2立方萤石相与钙钛矿相。当2θ在20°~30°变化时,Sr2+掺杂使Ln0.5Sr0.5CuO3-δ形成的钙钛矿结构衍射峰相对完整;当2θ在30°~45°变化时,Ca2+掺杂却使Ln0.5Ca0.5CuO3-δ钙钛矿结构衍射峰发生扭曲;而2θ在50°~60°时,Ln0.5Ca0.5CuO3-δ和Ln0.5Sr0.5CuO3-δ衍射峰发生了不同程度的偏移和裂变。直流四探针法对合成产物烧结样品的电导率测量结果表明,在相同条件下,Ln0.5Sr0.5CuO3-δ电导率大于Ln0.5Ca0.5CuO3-δ电导率,在420℃时电导率达到最大值,分别为574和559 S/cm。在中温固体氧化物燃料电池工作温度500~800℃,阴极材料电导率超过500 S/cm,满足电池阴极材料电性能的要求。

Preparation of Ln-Sr(or Ca)-Cu-O cathode materials and its electrical properties

In order to reduce the cost of raw materials the Ln-Sr(or Ca)-Cu-O(Ln is mixed rare earth) cathode materials precursors were prepared by the co-precipitation method after dissolved the mixed rare earth with nitric acid.The produced powder calcined at 800 ℃ for 3.5 h showed both cubic fluorite and perovskite phase.The diffraction peak of perovskite structure generated from Ln0.5Sr0.5CuO3-δ was relatively complete at 2θ angle ranged in 20°-30°.The diffraction peak of perovskite structure generated from Ln0.5Ca0.5CuO3-δ was distorted at 2θ angle ranged in 30°-45°.The diffraction peaks of both Ln0.5Ca0.5CuO3-δ and Ln0.5Sr0.5CuO3-δ were shifted and split to some extent at 2θ angle in 50°-60°.The electrical conductivity of Ln0.5Sr0.5CuO3-δ is higher than that of Ln0.5Ca0.5CuO3-δ and has the highest electrical conductivity at 420 ℃.The electrical conductivity is higher than 500 S/cm at its working temperature 500 to 800 ℃ of intermediate temperature solid oxide fuel cell(ITSOFC),which could meet the requirements of electrical properties of cathode materials.