SOFC阴极材料La_(0.8)Sr_(0.2)Co_(0.5)Fe_(0.5)O_(3-8)的制备与表征

Synthesis of La_(0.8)Sr_(0.2)Co_(0.5)Fe_(0.5)O_(3-8) and its characterization as SOFC cathodes material

提出一种低成本高效率的化学方法,用以制备钙钛矿结构固体氧化物燃料电池(SOFC)阴极材料La0.8Sr0.2Co0.5Fe0.5O3-8(LSCF).该方法与传统方法不同,采用非螯合聚合物-聚乙烯醇(PVA,Polvinyl alcohol)作为阳离子的载体,形成含有La3+,Sr2+,Co2+,Fe3+4种金属阳离子和非螯合聚合物的均匀溶胶,干燥生成固体凝胶状前驱体.进行热重(TG)分析和傅立叶红外(FT-IR)分析,在此基础上制定了一系列前驱体凝胶煅烧工艺制度,确定了最佳煅烧温度750℃,获得了钙钛矿型LSCF阴极材料.对LSCF粉末进行了X射线衍射(XRD)相分析,证实了所得粉末材料具有钙钛矿结构.通过扫描电子显微镜(SEM)对粉体进行微观形貌结构观察,证实制得的LSCF粉为纳米级,但存在团聚.采用直流伏安法检测其导电性能,证实以其作为阴极材料,在中温SOFC的工作温度下具有良好的混合导电性能.

A chemical method for fabricating SOFC cathode powder with low cost and high efficient is proposed. Different from conventional fabrication of cathode powder, non-chelating polymer polvinyl alcohol serves to sterically entrap the metal cations in a manner thewey which facilitates the formation of an atomistically homogeneous precursor material. And, calcining the solid precursor material to form a mixed metal oxide material, that is perovskite structured powder La0.8Sr0.2Co0.5Fe0.5O3 （LSCF）. Thermogravimetry （TG） analysis and Fourier transformation infrared radiation （FT-IR） is employed to determine the calcination temperature of the dried gels for forming perovskite structured LSCF; the optimized calcination temperature 750℃ is selected. X-ray diffraction （XRD） analysis is used to identify the crystal structure of the calcined powder; LSCF perovskite structure is established. The powder morphology of the LSCF is examined by scanning electronic microscope （SEM） ; nanosized particles in clusters are observed. Excellent mixed conductivity at SOFC operating temperatures as a cathode material is demonstrated by Ⅰ-Ⅴ measurement.