非化学计量(La_(0.6)Sr_(0.4))_xCo_(0.2)Fe_(0.8)O_(3-δ)阴极材料的制备与性能

Fabrication and characterization of non-stoichiometry(La_(0.6)Sr_(0.4))_xCo_(0.2)Fe_(0.8)O_(3-δ) cathode for SOFCs

采用溶胶凝胶法制备(La_(0.6)Sr_(0.4))_xCo_(0.2)Fe_(0.8)O_(3-δ)(x=0.95,0.97,1.00,1.03,1.05)系列阴极材料。采用X射线衍射(XRD)和扫描电子显微镜(SEM)对其结构和微观形貌进行表征,交流阻抗谱(EIS)测试样品的导电性能。结果表明,样品经750℃烧结3h形成斜方钙钛矿结构,A位非化学计量可明显降低阴极的极化电阻。在700℃时,x=1.05的样品界面极化电阻为0.086 3Ω·cm2,相比x=1.00的样品降低了50%,(La_(0.6)Sr_(0.4))_xCo_(0.2)Fe_(0.8)O_(3-δ)材料是一种电化学性能较为优良的中温固体氧化物燃料电池阴极材料。

（La_（0.6）Sr_（0.4））_xCo_（0.2）Fe_（0.8）O_（3-δ）（x=0.95,0.97,1.00,1.03,1.05）series cathode materials are prepared with sol-gel method.The structure and microstructure of sample are characterized by X-ray diffraction（XRD）and scanning electron microscope（SEM）,and the electrical conductivity are tested by electrochemical impedance spectrum（EIS）.Results indicate：orthorhombic perovskite structure is formed after sintering 3hours at 750℃;A-site of non-stoichiometry can obviously reduce the cathode polarization resistance.At 700 ℃,the interface polarization resistance is 0.086 3Ω·cm^2 when x=1.05,decreasing by 50% compared to x =1.00.（La0.6Sr0.4）xCo0.2Fe0.8 O3-δis a kind of medium temperature solid oxide fuel cell cathode materials with excellent electrochemical performance.