LOW TEMPERATURE SOLID OXIDE FUEL CELLS WITH ELECTROLYTES MADE BY ELECTROCHEMICAL VAPOR DEPOSITION (EVD)

RESEARCHERS ARE INVESTIGATING THE APPLICATION OF LOW TEMPERATURE SOLID OXIDE ELECTROLYTES IN FUEL CELLS. THERE ARE NUMEROUS OXYGEN ION CONDUCTORS WITH CONDUCTIVITIES GREATER THAN ZIRCONIA. HOWEVER, THEIR UTILIZATION DOES NOT OCCUR IN FUEL CELLS DUE TO THE HIGH LEVEL OF ELECTRONIC CONDUCTIVITY. ADDITIONALLY, THE USE OF ANY SOLID ELECTROLYTE IN FUEL CELLS RQUIRES THAT THE CELL RESISTANCE BY KEPT TO A MINIMUM. THUS, THE ELECTROLYTES MUST BE THIN. THE APPROACH CONSISTS OF FABRICATING TWO-LAYER, COMPOSITE ELECTROLYTES CONSISTING OF A CEO2-BASED OR PEROVSKITE-BASED SOLID ELECTROLYTE WITH HIGH IONIC CONDUCTIVITY UPON WHICH A THIN LAYER OF ZIRCONIA IS DEPOSITED BY ELECTROCHEMICAL VAPOR DEPOSITION (EVD) TO BLOCK OFF ELECTRONIC CURRENT. THE SUBJECT ELECTROLYTES ARE ABOUT 30 MICRONS IN THICKNESS. THE ZIRCONIA LAYER PERMITS THE ATTAINMENT OF THEORETICAL OPEN CIRCUIT POTENTIAL. POWER DENSITIES IN EXCESS OF 500 MW/CM2 OCCUR AT TEMPERATURES AS LOW AS ~700 DEGREES CENTIGRADE. THE MATERIALS SELECTED FOR THIS WORK ARE: Y203-DOPED CEO2, BATB0.9IN0.1O3, AND OTHER PREOVISKITES.