Solid Oxide Fuel Cells damage mechanisms due to Ni-YSZ re-oxidation: Case of the Anode Supported Cell
Solid Oxide Fuel Cells damage mechanisms due to Ni-YSZ re-oxidation: Case of the Anode Supported Cell
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DOI：
10.1016/j.jpowsour.2009.02.089
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发表时间：
2009-07
影响因子：
9.2
通讯作者：
J. Laurencin;G. Delette;B. Morel;F. Lefebvre-Joud;M. Dupeux
中科院分区：
文献类型：
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作者：
J. Laurencin;G. Delette;B. Morel;F. Lefebvre-Joud;M. Dupeux
研究了阳极支持的固体氧化物燃料电池 (SOFC) 中 Ni-YSZ 金属陶瓷再氧化的影响。已经研究了空气中直接氧化（即燃料关闭）或离子电流（即燃料不足）两种情况下的损坏机制。直接氧化测试表明，当 Ni 转化为 NiO 的程度在~58% 和~71% 之间时，电解质会发生裂纹。这种失效模式的建模考虑了镍相转变引起的金属陶瓷的体积膨胀和多层电池中机械应力的变化。在燃料匮乏的情况下，金属陶瓷薄层在 800°C 下进行电化学再氧化，然后在氢气流下还原。重复这种“氧化还原”循环，直到细胞降解。每个循环后记录的阻抗图的演变表明金属陶瓷在靠近阳极/电解质界面的区域中损坏。机械模型表明，沿阳极功能层 (AFL) 和阳极集流体 (ACC) 基板之间的界面可能会发生分层。这一理论结果证实了阻抗谱观察到的实验趋势。
The effects of Ni-YSZ cermet re-oxidation in anode supported Solid Oxide Fuel Cells (SOFCs) have been investigated. Damage mechanisms have been studied in both cases of direct oxidation in air (i.e., fuel shutdown) or by an ionic current (i.e., fuel starvation). Direct oxidation tests show that the electrolyte cracks for a conversion degree of Ni into NiO ranging between ∼58 and ∼71%. This failure mode has been modelled considering both the bulk expansion of the cermet induced by the transformation of the Ni phase and the change of mechanical stresses in the multilayered cell. In the case of fuel starvation, a thin layer of the cermet was electrochemically re-oxidised at 800°C and then reduced under a hydrogen stream. This ‘redox’ cycle was repeated until the degradation of the cell. The evolution of the impedance diagrams recorded after each cycle suggests that the cermet damages in an area close to anode/electrolyte interface. The mechanical modelling states that a delamination can occur along the interface between the Anode Functional Layer (AFL) and the Anode Current Collector (ACC) substrate. This theoretical result confirms the experimental trends observed by impedance spectroscopy.