Properties of Partially Stabilized Zirconia Fuel Cell

Abstract

Much attention has been focused on the solid oxide fuel cell (SOFC). The tubular configuration is being developed by Westinghouse Corporation and pilot plant facilities are operated in the 1 to 5kW range. The other SOFC configurations have now been proposed: monolithic SOFC and planar configuration SOFC. Fully stabilized zirconia (FSZ) was applied to SOFC as electrolytes, since FSZ offers a superior oxygen conductivity. However, yttria doped zirconia has three different modifications: monoclinic, tetragonal, and cubic phases. In FSZ, a high yttria doping retains the normal high-temperature cubic over a wide range of temperature. Partially stabilized zirconia (PSZ), with a lower concentration of yttria dopant, consists mainly of the tetragonal phase and possesses a high strength and a high toughness despite the fact that FSZ is brittle. The mechanical properties of PSZ seem to be derived from the stress-induced tetragonal to monoclinic transition, which may provide an ambiguity on long term stability at high temperature. Advances in ceramics technology allow the fabrication of thin PSZ sheets below the thickness of 0.25 mm. The thin PSZ sheets could provide a new assembly of SOFC through PSZ sheets conductivity is one order lower than that of 1000{degrees}C. Thus, a thin PSZ sheetmore » is a good candidate for a SOFC electrolyte. In this paper, the properties of SOFC using PSZ as an electrolyte are presented.« less