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Reducing Number Of Infiltration Cycles For La0.8sr0.2feo3 Ysz Cathodes

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Independent Study Report
Reducing Number of Infiltration Cycles for La0.8Sr0.2FeO3-YSZ Cathodes
Xiaoyan Li
Abstract
In order to decrease the number of cycles of infiltration and maintain a comparable cathode performance, the viability of using a conductive composite scaffold of La0.8Sr0.2FeO3 and yttria-stablized zirconia (YSZ) with one infiltration cycle was investigated. The infiltration material is nitrate salt solution of La, Sr, Co and Fe to form La0.6Sr0.4Co0.2Fe0.8O3 perovskite phase. Cathodes fabricated from scaffolds using different ratios of LSF-YSZ were tested by impedance spectroscopy with the results showing that the ohmic resistance decreases as the amount of LSF increases. In addition, scaffolds calcined at 1350oC exhibited …show more content…

1,2 In this case, YSZ is included in the cathode to provide ionic conductivity, as well as enhancing the connection between the electrode and the YSZ electrolyte. YSZ in the electrode also helps match the thermal expansion of the electrode to the electrolyte.1-4 The functions of LSM in the composite cathode include providing electronic conductivity and catalytic activity, but with negligible contributions to ionic conductivity.4,5
The conventional method for fabricating the electrode is to deposit and sinter a mixture of the electrode composites onto a dense YSZ electrolyte.4 The sintering temperature must be a compromise, high enough to ensure the good connection between YSZ in the electrode and the electrolyte, but low enough to prevent solid state reactions between the electrode composites.2,5 Indeed, most conducting perovkites are unable to be prepared due to the formation of insulating phases at high temperatures required for YSZ sintering.4 Therefore, the infiltration method was initially developed to separate the high calcination temperature required to densify the YSZ electrolyte from the lower calcinations temperature needed for the other electrode components.1,4,5 Furthermore, the infiltration method provides a nonrandom structure where the electronically conductive components are deposited into the previously formed porous YSZ scaffold.1-4 Infiltration also forms superior

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