A cobalt-free composite cathode prepared by a superior method for intermediate temperature solid oxide fuel cells

Cobalt-free Sm0.6Sr0.4FeO3−δ–Ce0.8Sm0.2O2−δ (SSF–SDC) composite powders are prepared by a newly one-step synthesis method, co-synthesis method. Powders XRD analysis shows that the composite powders exhibit the consistent phase structure with powders derived from traditional method, which demonstrate that the SSF is compatible with SDC. Dry-mixing method, a traditional composite cathode preparation method, is used to obtain SSF–SDC composite cathode as a comparison. The two cathodic composites of microstructures, electrical conductivities and symmetric electrochemical cells are characterized under the same condition. As a result, powders from new method show superior microstructure, high electrical conductivity and good electrochemical properties. Finally, cathode preparing from new method is evaluated by an anode-supported SDC-electrolyte single cell testing. To further study SSF–SDC cathode, the thermal expansion coefficient and thermal cycling performance are measured. The all results imply that co-synthesis method is a facile and practical way to improve the cathode properties and SSF–SDC is a promising cathode for intermediate temperature SOFCs.

► SSF–SDC cathode powders were prepared by two different routes.
► SSF–SDC samples derived from new method showed high electrical conductivity and good catalytic activity.
► The ASRs of SSF–SDC is comparable to those of other cobalt-free cathode.
► The SSF–SDC cathode owns good thermal cycle stability.