SOLID OXIDE FUEL CELL MULTI-LAYER CERAMIC STRUCTURES WITH IMPROVED THERMAL CYCLING PROPERTIES

THE OBJECTIVE OF THIS PROJECT IS TO DEVELOP MATERIALS FOR USE IN SOLID OXIDE FUEL CELLS (SOFCS) THAT WILL RESIST DELAMINATION OF THE MULTILAYER CERAMIC STRUCTURE DURING FABRICATION, STARTUP, SHUTDOWN, AND LOAD CYCLING OF THE FUELCELL POWERPLANT. DELAMINATION OF THESE MULTILAYERED CERAMICS RESULTS IN DEGRADED PERFORMANCE AND REDUCED LIFETIMES FOR SOFCS THROUGH GAS LEAKAGE AND INCREASED INTERFACIAL RESISTANCES IN THE CELLS. THE DELAMINATION IS CAUSED PRIMARILY BY DIFFERENCES IN SHRINKAGE RATES DURING INITIAL FIRING OF THE CERAMICS AND BY THE THERMAL COEFFICIENTS OF EXPANSION (TCE) OF THE VARIOUS LAYER MATERIALS. THE APPROACH IN THIS PROJECT IS TO USE NEW FABRICATION TECHNIQUES FOR CURRENTLY USED SOFC ELECTRODE ANDELECTROLYTE MATERIALS AND TO INVESTIGATE NEW MATERIALS AND MATERIAL FORMS THAT CAN BE USED WITH CURRENTLY USED COMPOUNDS. IN PHASE I OF THIS PROJECT, INVESTIGATION WILL DEMONSTRATE THE NEW FABRICATION TECHNIQUES AS WELL AS APPLICATION OF THESE TECHNIQUES TO NEW MATERIALS EXPECTED TOBE USEFUL IN CONTROLLING THE TCE OF SOFC STRUCTURES. IN PHASE II, THE NEW SOFC COMPONENT FORMULATIONS ARE TO BE OPTIMIZED, AND A DEMONSTRATION MONOLITHIC SOFC IS TO BE FABRICATED.