DEVELOPMENT OF SOLID OXIDE FUEL-CELLS BASED ON A CE(GD)O2-X ELECTROLYTE FILM FOR INTERMEDIATE TEMPERATURE OPERATION

Initial tests have been carried out with the fuel cell arrangement La0 .6Sr0.4Co0.2Fe0.8O3 parallel to Ce(0.9)Gd(0.1)O(1.95)parallel to Ni/YS Z, incorporating dense film (5-10 mu m) Ce0.9Gd0.1O1.95 electrolyte ta pe cast onto the supporting anode, to investigate the feasibility of i ntermediate temperature operation (500-700 degrees C). A good open cir cuit voltage of approx. 0.8 V was obtained at 550 degrees C using mois t hydrogen as the fuel. Slightly lower open circuit voltages were foun d at higher temperatures, which may have been caused by minor gas leak age and the electronic conductivity of the electrolyte. Power outputs in excess of 100 mW/cm(2) were obtained at 650 degrees C, and the cell resistance was 0.8 Omega cm(2) at this temperature. This resistance, and the greater resistance at lower temperature, was predominantly due to the cathode according to AC impedance measurements. Experiments we re also carried out at 600 degrees C using direct methanol fuels at th e anode; the maximum power output was approximately half of that obtai ned with hydrogen. (C) 1997 Elsevier Science B.V.