| Solid oxide fuel cell?SOFC?is a new generation of efficient energy generation devices.The anode material is the most important component in SOFC.Its catalytic performance directly determines the battery's ability to do external power.The search for good anode materials is therefore essential.In this paper,the glycine-nitrate method is used to prepare Fe-GDC and Fe-Co-GDC anode materials,where quantity ratios of Fe of Co are 9:1,8:2,7:3,6:4,5:5,and4:6,respectively.Studies on the preparation and electrical properties of Fe-GDC and Fe-Co-GDC composite anode materials were carried out.Fe-GDC powder was calcined at 800?for 2 hours,and the phase composition characterization showed that Fe2O3 and GDC phases were obtained.After H2 reduction,Fe and GDC phases were obtained.The Fe-GDC powder was pressed into square cylinders and sintered at 900?-1300?.The conductivities were tested by a DC four-electrode method after hydrogen reduction.Considering the low melting point characteristics of the subsequently added Co and the minimum conductivity requirement of SOFC for the anode(?100S·cm-1),1200?was chosen as the most appropriate sintering temperature.The thermal expansion coefficient of Fe-GDC material is about 10.84×10-6K-1,which is closer to the thermal expansion coefficient of GDC electrolyte(11.16×10-6K-1).Fe-Co-GDC anode and GDC electrolyte have good thermal expansion compatibility.The measurement results showed that the thermal expansion coefficient of Fe-Co-GDC anode increases and then decreases with the Co content.The thermal expansion coefficient of Fe0.6Co0.4-GDC anode(11.74×10-6K-1)is the largest among six species.An electrolyte-supported solid oxide fuel single cell with Fe-GDC and Fe-Co-GDC as the anode respectively,GDC as the electrolyte and La0.6Sr0.4Co0.2Fe0.8O2.7-GDC as the cathode?30wt%?was assembled by screen-printing method.Two-electrode method was used to test the electrochemical properties of the single cell.It can be seen from the battery output characteristic curve that the maximum power density increases and then decreases with Co content increasing.Among Fe-Co-GDC anode materials,6:4 is the best ratio for single cell performance with the maximum output power density of 168.94mW·cm-2 at 750?,which is much higher than Fe-GDC(40.02mW·cm-2)single cell performance.The addition of the appropriate amount of Co2O3 in Fe2O3 can generate CoFe2O4,and CoFe solid solution was formed after reduction,which greatly improved the battery performance,with a minimum polarization resistance of0.313?·cm2 for a single cell. |
PDF Full Text Request