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 u sing the solid method and formed by plaster casting technique to make an el ectrolyte of a solid oxide fuel cell (SOFC). The densities of the obtained samples increase as the sintering temperature increases. The relative densi ty of the sample sintered at 1550 degrees C is 93%. Gas-tight can be realiz ed 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 sin tered above 1300 degrees C. The results of SEM measurement show that as the sintering temperature is raised, the crystal grain size of the sample incr eases and the porosity decreases. The results obtained by measuring the ele ctrical properties show that, under the same temperature, the grain resisti vities of the samples sintered at different temperatures are almost the sam e, but the crystal boundary resistivities are different. It can be calculat ed from the experimental results that the conductive activation energy of t he crystal boundary for the samples sintered at 1300 degrees C, 1400 degree s C, and 1550 degrees C is 0.66, 0.86 and 0.98 eV, respectively, and that o f the grain for the samples sintered at different temperatures is 0.82 eV. Spigot-shaped electrolyte components are made using the above mentioned tec hnique, and a two-cell-series SOFC is set up. Its maximum output is about 0 .1 W/cm(2) at 930 degrees C. (C) 1999 published by Elsevier Science B.V. Al l rights reserved.