SOFC阴极材料La0.7Sr0.3Fe0.7Co0.2Ni0.1O3-δ的制备与性能

Synthesis and properties of La0.7Sr0.3Fe0.7Co0.2Ni0.1O3-δ cathode material for solid oxides fuel cell

采用溶胶-凝胶法、固相法制备La0. 7Sr0. 3Fe0. 7Co0. 2Ni0. 1O3-δ(LSFCN)中低温固体氧化物燃料电池阴极材料,通过热重-差热分析、X射线衍射、扫描电镜、直流四探针法、热膨胀系数、交流阻抗对材料的结构与性能进行研究。结果表明,2种方法制备的LSFCN均为单一的钙钛矿结构,并且与电解质SDC在950℃以下没发生化学反应,稳定性较好。溶胶-凝胶法制备的阴极粉体颗粒最小、形状规整、结晶度高。在测试温度400~800℃条件下,2种方法合成的阴极材料LSFCN是小极化子导电机制,电导率随着测试温度的升高而增大。溶胶-凝胶法制得的LSFCN的电导率均大于固相法,在800℃时最大达到619. 4S/cm。2种方法制备的LSFCN阴极样品与电解质SDC匹配性好。2种方法制备的LSFCN有利于氧在三相界面的传输,提高了材料的电化学性能。

La0.7Sr0.3Fe0.7Co0.2Ni0.1O3-δ(LSFCN),a cathode material for medium and low temperature solid oxides fuel cell,is prepared by sol-gel method and solid state reaction method,respectively.The structure and properties of the material are measured by thermogravimetry-differential thermal analysis(TG-DTA),X-ray diffractometry(XRD),scanning electron microscopy(SEM),four-probe DC method,thermal expansion coefficient(TEC)and alternatingcurrent impedance.It is shown that LSFCN prepared by two methods both have a single perovskite structure and do not react with the electrolyte SDC during 950℃calcination,meaning a good stability.LSFCN prepared by sol-gel method has a smaller particle size,a more regular shape and a higher crystallinity.Both LSFCN by two methods exhibit a conductivity mechanism of small polaron at the test temperature of 400-800℃,their conductivities increase with the increase of the test temperature.The conductivity of LSFCN prepared by sol-gel method is higher than that of LSFCN prepared by the solid state reaction method.The maximum conductivity of LSFCN reaches 619.4 S·cm-1 at 800℃.LSFCN cathode samples prepared by the two methods have a good match with SDC electrolyte,and both are favorable for oxygen transfer through three-phase interface,which can improve the electro chemical properties of the materials.