Abstract
Experimental studies using conventional (porous) solid oxide fuel cell (SOFC) electrodes are often rather difficult to interpret in terms of a mechanistic understanding of the electrochemical polarization phenomena. Owing to the complex morphology and structure of porous electrodes, a quantitative determination of the properties of the electrochemical materials rather than of the effective electrode properties is far from being straightforward. Micro‐patterned epitaxially grown thin film electrodes offer new possibilities in this field of research. This is particularly true for microelectrodes of several 10 μm diameter, fabricated lithographically from thin films. They allow well‐defined geometry‐dependent experiments, minimize the importance of ohmic drops, and avoid the necessity of a reference electrode. Further, they turn out to be particularly well‐suited for statistical studies, as well as for the investigation of irreversible processes. Hence, thin‐film microelectrodes are an excellent tool for the investigation of SOFC electrode materials. This is exemplified by p(O~2~)‐, voltage‐, and geometry‐dependent measurements on (La~0.8~Sr~0.2~)~0.92~MnO~3~ and La~0.6~Sr~0.4~Co~0.8~Fe~0.2~O~3–δ~ microelectrodes on single‐crystal yttria‐stabilized zirconia electrolytes.