首页> 外文期刊>International journal of hydrogen energy >Activation and failure mechanism of La_(0.6)Sr_(0.4)Go_(0.2)Fe_(0.8)O_(3-δ) air electrode in solid oxide electrolyzer cells under high-current electrolysis
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Activation and failure mechanism of La_(0.6)Sr_(0.4)Go_(0.2)Fe_(0.8)O_(3-δ) air electrode in solid oxide electrolyzer cells under high-current electrolysis

机译:大电流电解条件下La_(0.6)Sr_(0.4)Go_(0.2)Fe_(0.8)O_(3-δ)空气电极在固体氧化物电解槽中的活化和破坏机理

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This work investigates the activation and delamination of La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF) air electrode of solid oxide electrolyzer cells sintered on yttria-stabilized zirconia (YSZ) electrolyte. After polarization with an electrolysis current of 1 A cm(-2) for 24 h at 800 degrees C, the LSCF electrode delaminates accompanied by an increase of ohmic and polarization resistance. Notably, polarization resistance decreases at the beginning. By scanning electron microscopy (SEM), a thin but dense layer is observed at the LSCF YSZ interface of an as prepared sample, which is identified as SrZrO3 phase by X-ray diffractometry. This layer causes the initial high polarization resistance due to retarded ionic and electronic conductivity. After the test, SEM reveals that the SrZrO3 layer delaminates from YSZ electrolyte. Moreover, energy dispersive X-ray tests confirm that Co diffuses to the SrZrO3 layer and SrZrO3 YSZ interface. Later, the LSCF electrode with Co-containing SrZrO3 layer is shown to perform better than that with pure SrZrO3 layer. Thus, Co diffusion can be the reason for the initial decrease of polarization resistance and renders the generation of oxygen at SrZrO3-YSZ interface during the electrolysis. Owing to its limited porosity, the SrZrO3 layer traps the generated oxygen. High pressure eventually builds up at the SrZrO3 YSZ interface driving the delamination of SrZrO3 layer, and hence the entire LSCF electrode. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
机译:这项工作研究了在氧化钇稳定的氧化锆(YSZ)电解质上烧结的固体氧化物电解槽中La0.6Sr0.4Co0.2Fe0.8O3-δ(LSCF)空气电极的活化和分层。在800摄氏度下用1 A cm(-2)的电解电流极化24小时后,LSCF电极分层,并伴随着欧姆电阻和极化电阻的增加。值得注意的是,极化电阻在开始时降低。通过扫描电子显微镜(SEM),在制备样品的LSCF YSZ界面上观察到薄而致密的层,该样品通过X射线衍射法鉴定为SrZrO3相。该层由于离子和电子传导性的降低而导致初始的高极化电阻。测试后,SEM显示SrZrO3层与YSZ电解质分层。此外,能量色散X射线测试证实Co扩散到SrZrO3层和SrZrO3 YSZ界面。后来,具有含Co的SrZrO3层的LSCF电极表现出比具有纯SrZrO3层的LSCF电极更好的性能。因此,Co扩散可能是引起极化电阻初始降低的原因,并且在电解过程中会在SrZrO3-YSZ界面处产生氧气。由于其有限的孔隙率,SrZrO3层会捕获产生的氧气。最终在SrZrO3 YSZ界面处形成高压,从而驱动SrZrO3层分层,从而驱动整个LSCF电极分层。 (C)2018氢能出版物有限公司。由Elsevier Ltd.出版。保留所有权利。

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