Co-planar type single chamber solid oxide fuel cell with micro-patterned electrodes

Abstract

A co-planar type single chamber solid oxide fuel cell (SC-SOFC) with linearly patterned electrode structures on the same surface as the electrolyte has been fabricated by robo-dispensing method. Paste materials of NiO-SDC-Pd cermet and (La 0.7 Sr 0.3 ) 0.95 MnO 3 (LSM) were selectively deposited onto a substrate of yttria stablized zirconia (YSZ) by extrusion through a syringe nozzle. The dispensed pastes were solidified upon solvent evaporation, and the anode and the cathode were sintered at 1350 • C for 2 h and 1200 • C for 1h, respectively. We have fabricated SC-SOFCs that have a single electrode pair with varying anode-to-cathode distances and interdigitated patterned electrodes with 2, 4, and 8 multiple pairs. The electrode microstructures of the resulting cells were examined by SEM. The electrochemical performance of the SC-SOFCs was also analyzed using impedance spectroscopy and a DC source meter.

Single-Chamber Solid Oxide Fuel Cell Technology—From Its Origins to Today’s State of the Art

“…In contrast to [180,185] where an increasing number of electrode pairs led to OCVs below 0.8 V, an OCV of 0.8 V was obtained for an interdigitated electrode structure of 5 pairs of Ni-YSZ anode and LSM cathode lines on a YSZ electrolyte [149]. However, oscillations of the cell voltage between 0.4 and 0.8 V were observed during cell aging, probably due to Ni oxidation-reduction cycles and nickel volatilization.…”

“…A dependence of the OCV on the number of electrode pairs was observed for Ni-GDC-Pd anodes and LSM(-GDC) cathodes on a YSZ electrolyte [180,185]. When the number of electrode pairs was increased from 1 to 8, the OCV decreased from 0.8 to 0.4 V. The OCV drop was attributed to an increased system complexity, where the intermixing of reaction products was enhanced and the oxygen partial pressure at the cathode was reduced.…”

“…Reducing the inter-electrode distance from 5 to 0.5 mm led to an increase in the maximum current from 8 to 24 mA at 950 °C in a methane-oxygen mixture (R mix = 2). The OCV was found to be independent of the variation of the inter-electrode gap [180,184,185], which principally affected the ohmic resistance of the electrolyte [147].…”

“…Low OCVs below 0.4 V were obtained at R mix = 1, whereas OCVs over 0.5 V could only be measured for higher R mix , with a maximum at R mix = 5. For single electrode lines [185] and micro-electrode arrays [189], R mix = 3.75 was necessary for operation in methane-air mixtures at 900 °C. However, such high R mix values are unsuitable for cell operation, as they favor carbon formation and restrain performance [50].…”

“…This technique was applied to the fabrication of SC-SOFCs with coplanar single and multiple, interdigitated electrode pairs of conventional SOFC materials [104,149,151,177,180,184,185,[202][203][204][205]. Inter-electrode distances ranging from 255 to 783 m (electrode width of approximately 0.6 mm) [180,185] and electrode widths from 93 to 1,380 m (inter-electrode gap of approximately 250 m) [151] were reported for single electrode pairs. Interdigitated electrode structures were fabricated with average gaps of about 300 m (electrode width of 600 m [180] and 140 m [149,204]) and 114 m (electrode width of 260 m) [151].…”