Micro solid oxide fuel cell fabricated on porous stainless steel: a new strategy for enhanced thermal cycling ability.

Kun Joong Kim,Byung Hyun Park,Younki Lee,Gyeong Man Choi,Sun Jae Kim,Hongyeul Bae

doi:10.1038/srep22443

Abstract

Miniaturized solid oxide fuel cells (micro-SOFCs) are being extensively studied as a promising alternative to Li batteries for next generation portable power. A new micro-SOFC is designed and fabricated which shows enhanced thermal robustness by employing oxide-based thin-film electrode and porous stainless steel (STS) substrate. To deposit gas-tight thin-film electrolyte on STS, nano-porous composite oxide is proposed and applied as a new contact layer on STS. The micro-SOFC fabricated on composite oxide- STS dual layer substrate shows the peak power density of 560 mW cm−2 at 550 °C and maintains this power density during rapid thermal cycles. This cell may be suitable for portable electronic device that requires high power-density and fast thermal cycling.

Highlights

Micro-SOFC with this design was not investigated
An area porosity ε of LSTN-YSZ surface obtained from binary images, increased from 14 to 18% after surface polishing and a RMS value decreased from ~44 nm to ~21 nm after surface polishing (Supporting Information, Fig. S1), the porosity and surface roughness are appropriate for deposition of 2-μm-thick and dense electrolyte
The active area could be enlarged by careful control of surface defects in the LSTN-YSZ contact layer

Summary

Degradation rate

Micro-SOFC with this design was not investigated. We use an alternative contact layer, La-doped SrTiO3 (LST), due to its TEC comparable to that of the YSZ and STS, high electronic conductivity and redox stability. If this material is mixed with YSZ, both good compatibility and nanoporous microstructure can be obtained due to limited sintering or grain growth. LST-YSZ composite may be appropriate as a substrate to deposit gas-impermeable thin-film electrolyte. A newly designed dual-layer substrate (LSTN-YSZ/STS) was fabricated by simple co-firing. A thin-film of oxide-based electrode and electrolyte was deposited in a manner similar to one described previously[16]. To the best of our knowledge, this is the first demonstration of the ability of the thermal robustness of micro-SOFC, which has never been attained in many conventional Si-based devices

Experimental procedures

Results and Discussion

Author Contributions

Additional Information