Synthesis and characterization of nanocrystalline yttria-stabilized zirconia for an electrolyte in a solid-oxide fuel cell

We synthesized various sizes of nanocrystalline yttria-stabilized zirconia (YSZ) for an electrolyte in solid-oxide fuel cell (SOFC) by using the sol-gel method. The surface morphology and the thermo-mechanical properties for different nano-grain sizes were characterized. The YSZ grains were found to grow non-linearly, as well as non-logarithmically, with increasing sintering temperature. The surface morphology shows that the grains of nano-sized YSZ are well dispersed in the measured area, with a narrow size distribution and without significant aggregation. The values of the thermal expansion coefficient of nano-grain YSZ obtained in this study are close to those of the other components of the electrodes and the interconnects used in the SOFC. The effect of the grain size on the thermo-mechanical property is also found to be negligible.