Performance Degradation of Microtubular SOFCs Operating in the Intermediate-Temperature Range

Decreasing the operating temperature of solid oxide fuel cells (SOFCs) can reduce degradation of cell and stack materials and can reduce the cost of these materials as well through the use of metallic materials. These qualities have motivated the development of microtubular SOFCs for operation in the intermediate temperature range between 450 and 500 degrees C. In this study microtubular SOFCs are fabricated and tested for analysis of start-up behavior and electrochemical properties under various conditions in the intermediate temperature range. Start-up behavior, performance at varying flow rates of fuel, and performance during load cycling is investigated. The impedance spectra and current-voltage performance from individual 1.8 mm diameter, 1.2 cm length microtubular SOFCs are obtained for the intermediate temperature range. The microtubular SOFC investigated is anode-supported, consisting of a NiO and Gd0.2Ce0.8O2-x (GDC) cermet anode, thin GDC electrolyte, and a La0.6Sr0.4Co0.2Fe0.8O3-y and GDC cermet cathode.