Effects of applied current density and thermal cycling on the degradation of a solid oxide fuel cell cathode
Effects of applied current density and thermal cycling on the degradation of a solid oxide fuel cell cathode
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DOI：
10.1016/j.ijhydene.2018.04.175
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发表时间：
2018-07
影响因子：
7.2
通讯作者：
Muhammad Zubair Khan;M. Mehran;R. Song;Seung-Bok Lee;Tak-Hyoung Lim
中科院分区：
文献类型：
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作者：
Muhammad Zubair Khan;M. Mehran;R. Song;Seung-Bok Lee;Tak-Hyoung Lim
研究了外加电流密度和热循环对固体氧化物燃料电池(SOFC)阴极耐久性的影响。制备了带有和不带有GdC(GDC)中间层的SOFC半电池，并在不同的电流密度和热循环下，在900℃下进行了1000h的测试。通过面积比电阻(ASR)的增加来评估半电池的性能退化。最初，由于阴极激活，没有GDC过渡层的半电池的ASR下降了约150h，然后增加。在较高的外加电流密度下，ASR迅速增加，这归因于由于锶锆酸盐的形成导致电解液/阴极界面的分层，以及阴极微观结构的变化。然而，GDC夹层可以防止这些不良反应。与没有GDC夹层的半电池相比，有GDC夹层的半电池的降解率较小。在热循环试验中，所有GDC夹层厚度单元的ASR值都随着热循环次数的增加而增加。GDC中间层厚度为3.4μm的热循环电池由于致密的GDC中间层显示出较低的降解速率，这导致了较小的界面电阻，并阻止了元素向电解液的扩散。然而，当GDC中间层厚度分别为2.4和4.5μm时，由于阴极/GDC中间层界面的相对较高的锶扩散和分层，半电池的ASR增加较大。
Effects of applied current density and thermal cycles on the durability of a solid oxide fuel cell (SOFC) cathode have been studied. SOFC half-cells with and without a gadolinium-doped ceria (GDC) interlayer were fabricated and tested for 1000 h at 900 °C under various current densities and thermal cycles. Performance degradation of the half-cells was assessed by increment of the area specific resistance (ASR). Initially, the ASR of the half-cells without the GDC interlayer decreased for around 150 h due to cathode activation and thereafter increased. A rapid increase in the ASR was observed at higher applied current density, which is attributed to delamination of the electrolyte/cathode interface due to the formation of Sr zirconates, and microstructural change in the cathode. However, these adverse effects were prevented by the GDC interlayer. The half-cells with the GDC interlayer exhibited a smaller degradation rate as compared to that without the GDC interlayer. During the thermal cycling test, ASR values of all GDC interlayer thickness cells increased with an increasing number of thermal cycles. The thermally cycled cell with a GDC interlayer thickness of 3.4 μm showed a lower degradation rate due to the dense GDC interlayer, which resulted in less interfacial resistance and prevented elemental diffusion towards the electrolyte. However, the half-cells with GDC interlayer thickness of 2.4 and 4.5 μm showed a higher increase in the ASR due to relatively higher Sr diffusion and delamination of the cathode/GDC interlayer interface, respectively.