Recently, increasing research efforts have been paid for developing
micro-solid oxide fuel cells (micro-SOFC) to apply those to high
performance portable and mobile power sources. This is owing to the
merits of SOFCs, such as high power and energy density, system
efficiency, and fuel flexibility [1–12]. To realize miniaturized SOFC
systems for portable applications, operating temperature decrease
without performance compromise should be accomplished for cutting
down the burden in the thermal management [1–6].
In an attempt to lower the operation temperature of the SOFC,
reducing the electrolyte thickness [1,3–7,9–11] has beenwidely studied.
Especially in the field of the micro-SOFC, thin electrolytes have been
fabricated using thin film deposition. Less than one micron-thick thin
electrolyte layersweremostly realized in backside etched free-standing
membrane designs [3–10]. However, the free-standing membrane
structure has a significantweakness in the thermal–mechanical stability
of the thin membrane [13]; and it is very complicated to obtain a
mechanically stable free-standing membrane structure in an actual
SOFC operating condition where the temperature reaches at least
several hundred degree Celsius. Due to the structural weakness, it is
often reported that themicro-SOFCs of free-standingmembrane designs
showed scattered results in open circuit voltage (OCV) values and cell
performances [4,6,8].