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| Home > Publications database > The development of full-ceramic solid oxide cells in research centre Juelich |
| Home > Publications database > The development of full-ceramic solid oxide cells in research centre Juelich |
| Conference Presentation (Invited) | FZJ-2019-03631 |
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2019
Abstract: Full ceramic fuel-electrodes have been widely considered as alternatives to the state-of-the-art Ni-YSZ cermets in solid oxide cells (SOCs) because of their high redox stability and low coking risk. Among the reported redox-stable ceramic materials, donor-substituted SrTiO3 shows best potential because of i) high electrical conductivity after heat treatment in reducing atmosphere, ii) matching thermal expansion to that of YSZ, and iii) good dimensional stability upon redox cycling. Research centre Juelich started SOC development based on donor-substituted SrTiO3 since 2005. Besides the materials development for the targeted conductivity, thermal expansion, chemical expansion between reduction-oxidation conditions etc., fuel cell fabrication was initiated with optimized stoichiometry for La- or Y-substituted SrTiO3. Powders were prepared in kg amounts by spray pyrolysis. Ni-CGO infiltration was optimized as catalyst for electrode reaction. Fuel-electrode supported single cells in dimension from 5 × 5 cm2 to 13 × 13 cm2 were prepared for single cell testing or stack assembly. The high power output and redox stability of the cells have proven a considerable potential for practical use and prospect for commercial application. The testing results indicated a different electrode reaction mechanism than it is known from Ni-YSZ cermets. However, difficulties in terms of low mechanical strength of the substituted SrTiO3 materials have to be solved for realizing reliable stacking of the full ceramic fuel-supported cells. Novel air-electrodes based on the quasi-ternary system LaFeO3–LaCoO3–LaNiO3 were also developed to avoid the continuous depletion of strontium in the state-of-the-art La1-xSrxFe1-yCoyO3 (LSCF) and La1-xSrxCoO3 (LSC) air-electrodes during the operation of SOCs, which leads to deterioration of electrical conductivity and electrocatalytic activity of the air-electrodes.
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