Study on the properties of YSZ electrolyte made by plaster casting method and the applications in solid oxide fuel cells

Yttrium stabilized zirconia (ZrO₂)_0.92(Y₂O₃)_0.08 (YSZ) is synthesized using the solid method and formed by plaster casting technique to make an electrolyte of a solid oxide fuel cell (SOFC). The densities of the obtained samples increase as the sintering temperature increases. The relative density of the sample sintered at 1550°C is 93%. Gas-tight can be realized as the thickness of the sample is 0.2 mm, so that it can be used as the electrolyte of an SOFC. Cubic fluorite structures appear in the samples sintered above 1300°C. The results of SEM measurement show that as the sintering temperature is raised, the crystal grain size of the sample increases and the porosity decreases. The results obtained by measuring the electrical properties show that, under the same temperature, the grain resistivities of the samples sintered at different temperatures are almost the same, but the crystal boundary resistivities are different. It can be calculated from the experimental results that the conductive activation energy of the crystal boundary for the samples sintered at 1300°C, 1400°C, and 1550°C is 0.66, 0.86 and 0.98 eV, respectively, and that of the grain for the samples sintered at different temperatures is 0.82 eV. Spigot-shaped electrolyte components are made using the above mentioned technique, and a two-cell-series SOFC is set up. Its maximum output is about 0.1 W/cm² at 930°C.