The composite cathode with lanthanum based iron and cobalt-containing perovskite La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) powder and Ce0.78Gd0.2Sr0.02O2-δ (GDCSr) nanofiber are investigated for IT SOFC. XRD measurements were done to identify phases of the structures. SEM was also carried out to determine the microstructures. Impedance spectroscopy measurements were performed in the air over the temperature 500-800°C. GDCSr nanofiber that was used in this composite cathode shows significantly larger diameter when using conventional rather than using microwave heating. Peak intensity in X-Ray diffraction pattern of GDCSr nanofiber using microwave heating was lower than using conventional heating. It indicates that the crystallinity of GDCSr nanofiber using microwave heating is worse due to less absorption of microwave energy for nanofiber. Selective heating properties of microwave give significant effect on the smaller diameter of GDCSr nanofiber, due to less absorbing of microwave energy for GDCSr material.
A mixing method was used to fabricate nanofibers composite cathode by adding various wt.% of GDCSr nanofibers (20, 50, and 80wt.%) into LSCF powder using conventional heating. Nanofibers play an important role to control porosity inside the composite cathode structure. Selective heating of microwave energy was successful to enhance the properties of composite cathode. Different microwave absorbability between GDCSr nanofiber and LSCF powder will affect the porosity of cathode structure thus determining the electrical performance. The existence of nanofibers really improves the properties of LSCF, such as the grain growth of LSCF could be suppressed, the porosity would be maintained, and the electrical properties of LSCF could be improved.
Microwave energy was used to heat the nanofiber composite cathode using mixing method to improve the performance. Experimental result shows that the cathode polarization resistance decrease, the exchange current density become higher, and the catalytic activity inside structure increase significantly. Moreover, microwave heating improves porosity of the composite cathode structure comparing with conventional heating, so better performance were found on materials using microwave heating. An effective porosity was about 30-40% for L8G2 obtained from microwave heating 1000 °C for 1 hour, in order to get lower cathode polarization resistance, activation energy, and higher exchange current density. At higher operating temperatures, it is found that the exchange current density of microwave heating increase significantly. It is proved that microwave energy also enhances the charge transfer properties of the composite cathode structure.
A sandwich method was investigated to improve nanofiber structure continuity of the mixing method. Enhancement of structure connection between nanofibers and powders causes higher performance of composite cathode made by sandwich method mixing method. The better electrical properties of nanofibers composite cathode was shown in this method because of more existence triple phase boundaries and connection between ionic conductors and electronic conductors. Continuity of nanofibers composite cathodes in the sandwich method using microwave energy was really improved, so electrical properties were also improved.

The composite cathode with lanthanum based iron and cobalt-containing perovskite La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) powder and Ce0.78Gd0.2Sr0.02O2-δ (GDCSr) nanofiber are investigated for IT SOFC. XRD measurements were done to identify phases of the structures. SEM was also carried out to determine the microstructures. Impedance spectroscopy measurements were performed in the air over the temperature 500-800°C. GDCSr nanofiber that was used in this composite cathode shows significantly larger diameter when using conventional rather than using microwave heating. Peak intensity in X-Ray diffraction pattern of GDCSr nanofiber using microwave heating was lower than using conventional heating. It indicates that the crystallinity of GDCSr nanofiber using microwave heating is worse due to less absorption of microwave energy for nanofiber. Selective heating properties of microwave give significant effect on the smaller diameter of GDCSr nanofiber, due to less absorbing of microwave energy for GDCSr material.
A mixing method was used to fabricate nanofibers composite cathode by adding various wt.% of GDCSr nanofibers (20, 50, and 80wt.%) into LSCF powder using conventional heating. Nanofibers play an important role to control porosity inside the composite cathode structure. Selective heating of microwave energy was successful to enhance the properties of composite cathode. Different microwave absorbability between GDCSr nanofiber and LSCF powder will affect the porosity of cathode structure thus determining the electrical performance. The existence of nanofibers really improves the properties of LSCF, such as the grain growth of LSCF could be suppressed, the porosity would be maintained, and the electrical properties of LSCF could be improved.
Microwave energy was used to heat the nanofiber composite cathode using mixing method to improve the performance. Experimental result shows that the cathode polarization resistance decrease, the exchange current density become higher, and the catalytic activity inside structure increase significantly. Moreover, microwave heating improves porosity of the composite cathode structure comparing with conventional heating, so better performance were found on materials using microwave heating. An effective porosity was about 30-40% for L8G2 obtained from microwave heating 1000 °C for 1 hour, in order to get lower cathode polarization resistance, activation energy, and higher exchange current density. At higher operating temperatures, it is found that the exchange current density of microwave heating increase significantly. It is proved that microwave energy also enhances the charge transfer properties of the composite cathode structure.
A sandwich method was investigated to improve nanofiber structure continuity of the mixing method. Enhancement of structure connection between nanofibers and powders causes higher performance of composite cathode made by sandwich method mixing method. The better electrical properties of nanofibers composite cathode was shown in this method because of more existence triple phase boundaries and connection between ionic conductors and electronic conductors. Continuity of nanofibers composite cathodes in the sandwich method using microwave energy was really improved, so electrical properties were also improved.

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