Global Research Center for Environment and Energy Based on Nanomaterials Science, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan.
ACS Appl Mater Interfaces. 2011 Jul;3(7):2772-8. doi: 10.1021/am2005543. Epub 2011 Jun 29.
The microstructure and local chemistry of the interface between the screen-printed La(0.6)Sr(0.4)Co(0.8)Fe(0.2)O(3) (LSCF) thin film cathode and Gd-doped ceria (GDC) electrolyte substrate have been investigated. Elemental distribution analyses, by energy-dispersive X-ray spectroscopy operated in scanning transmission electron microscopy (STEM) mode, illustrate that all constituent elements in GDC and LSCF mutually diffuse across the LSCF/GDC interface, with equal diffusion length. This leads to the formation of mutual diffusion zones at the LSCF/GDC interfaces, with the resultant mixture of diffusing ions being associated with specific valence state changes, as verified by STEM electron energy loss spectroscopy analyses. Moreover, this mutual diffusion can result in microstructural changes, where superstructure formation is accompanied by enhancement of oxygen vacancy ordering at this region. Such mutual diffusion and associated microstructure evolution is considered to be detrimental to fuel cell efficiency and should be suppressed by lowering cell fabrication temperatures.
已研究了丝网印刷的 La(0.6)Sr(0.4)Co(0.8)Fe(0.2)O(3)（LSCF）薄膜阴极与 Gd 掺杂氧化铈（GDC）电解质基底之间的界面的微观结构和局部化学。通过扫描透射电子显微镜（STEM）模式下的能量色散 X 射线能谱分析表明，GDC 和 LSCF 中的所有组成元素都相互扩散穿过 LSCF/GDC 界面，扩散长度相等。这导致 LSCF/GDC 界面处形成相互扩散区，扩散离子的混合与特定的价态变化有关，这通过 STEM 电子能量损失光谱分析得到证实。此外，这种相互扩散会导致微结构发生变化，其中超结构的形成伴随着该区域氧空位有序度的增强。这种相互扩散和相关的微观结构演化被认为对燃料电池效率有害，应通过降低电池制造温度来抑制。
