Microscopic and Nanoscopic Three‐Phase‐Boundaries of Platinum Thin‐Film Electrodes on YSZ Electrolyte
Microscopic and Nanoscopic Three‐Phase‐Boundaries of Platinum Thin‐Film Electrodes on YSZ Electrolyte
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DOI：
10.1002/adfm.201001729
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发表时间：
2011-02
影响因子：
19
通讯作者：
T. Ryll;H. Galinski;Lukas Schlagenhauf;P. Elser;J. Rupp;Anja Bieberle-Hutter;L. Gauckler
中科院分区：
文献类型：
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作者：
T. Ryll;H. Galinski;Lukas Schlagenhauf;P. Elser;J. Rupp;Anja Bieberle-Hutter;L. Gauckler
已经提出将团聚的Pt薄膜用作在低温下操作的电化学装置如微固体氧化物燃料电池（μ-SOFC）的电极。然而，阐明团聚状态和电化学性能之间的相互作用的综合研究是缺乏的。在这篇文章中，氧化钇稳定的氧化锆（YSZ）上的团聚和“致密”Pt薄膜电极的电化学性能与其微观结构特征相关。除了Pt、YSZ和空气接触的微观可测量三相边界（tpb）之外，还确定了“纳米级”tpb对由氧可渗透晶界产生的电极电导率的相当大的贡献。结果表明，“致密”的铂薄膜是优良的电极，其晶粒尺寸和厚度在纳米范围内。结果反驳了普遍的想法，铂薄膜电极的性能结果从微观和几何可测量的tpbs。
Agglomerated Pt thin films have been proposed as electrodes for electrochemical devices like micro‐solid oxide fuel cells (μ‐SOFCs) operating at low temperatures. However, comprehensive studies elucidating the interplay between agglomeration state and electrochemical properties are lacking. In this contribution the electrochemical performance of agglomerated and “dense” Pt thin film electrodes on yttria‐stabilized‐zirconia (YSZ) is correlated with their microstructural characteristics. Besides the microscopically measurable triple‐phase‐boundary (tpb) where Pt, YSZ and air are in contact, a considerable contribution of “nanoscopic” tpbs to the electrode conductivity resulting from oxygen permeable grain boundaries is identified. It is demonstrated that “dense” Pt thin films are excellent electrodes provided their grain size and thickness are in the nanometer range. The results disprove the prevailing idea that the performance of Pt thin film electrodes results from microscopic and geometrically measurable tpbs only.