| 1. |
- Darab, Mahdi, et al.
(author)
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Nanoengineered BSCF Cathode Materials for Intermediate-Temperature Solid-Oxide Fuel Cells
- 2009
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In: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 156:8, s. K139-K143
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Journal article (peer-reviewed)abstract
- A recently reported promising cathode material for solid-oxide fuel cells (SOFCs), namely, BaxSr1-xCoyFe1-yO3-delta (BSCF) is fabricated in nanocrystalline form by a chemical alloying approach. The approach is comprised of solution chemical synthesis of a precursor and its thermochemical processing toward the desired phase. All the constituent elements, Ba, Sr, Co, and Fe, were coprecipitated from an aqueous solution of their salts to produce a precursor with a well-defined composition, fine particle size, high homogeneity, and high reactivity. After calcining and sintering at 1000 degrees C, the individual oxides were alloyed into nanostructured perovskite (with x=0.5 and y=0.2) Ba0.5Sr0.5Co0.2Fe0.8O3 of high purity. Spark plasma sintering was used for compaction to preserve the material's nanostructure, and sintered compacts demonstrated a significant increase in electrical conductivity values at temperatures up to 900 degrees C, compared to the earlier reports. The measured conductivity values are sufficiently high for cathode applications with a maximum of about 63 S cm(-1) at 430 degrees C in air and 25 S cm(-1) at 375 degrees C in N-2, respectively. These values are about twice as high as conventional BSCF mainly due to the reduction in interfacial resistance, implying a high promise for nanoengineered BSCF as cathode material at low or intermediate-temperature SOFCs.
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| 2. |
- Toprak, Muhammet S., et al.
(author)
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Synthesis of nanostructured BSCF by oxalate co-precipitation - As potential cathode material for solid oxide fuels cells
- 2010
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In: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 35:17, s. 9448-9454
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Journal article (peer-reviewed)abstract
- BaxSr1-xCoyFe1-yO3 (BSCF) cathode material for solid oxide fuel cells (SOFC) was synthesized in nanocrystalline form by a novel chemical alloying approach. Thermodynamic modeling has been performed using Medusa software for obtaining the optimum conditions for the fabrication of a precursor with the desired composition. Precursor powder was then calcined and annealed to produce the final mixed oxide BSCF composition. The thermal properties, phase constituents, microstructure and elemental analysis of the samples were characterized by TGA, XRD, SEM and EDS techniques respectively. Spark Plasma Sintering (SPS) has been used at 1080 degrees C and under 50 MPa pressure to obtain the pellets of BSCF with preserved nanostructure and rather high compaction density for electrical conductivity measurements. The results show that the powders have cubic perovskite-type structure with a high homogeneity. Finer resultant powder, compared to earlier reports, and SPS sintered BSCF with nanosized grains exhibited a significantly higher electrical conductivity up to 900 degrees C. Specific conductivity values have been measured in air and N-2 and the maximum of 63 5 cm(-1) at 430 degrees C in air and 25 S cm(-1) at 375 degrees C in N-2 correspondingly show twice as much as conventional BSCF implying a high pledge for nano-BSCF as cathode material in intermediate-temperature SOFC. This is due to the lower interfacial resistance of preserved nanograins by the use of SPS sintering. Presented co-precipitation method is easy to handle and has a high promise to synthesize BSCF at large-scale for IT-SOFCs.
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