Stability and performance of nanostructured La0.8Sr0.2MnO3 cathodes deposited by spray-pyrolysis

• Porous LSM cathodes deposited on YSZ by spray pyrolysis.
• Low ASR values, 0.18 Ωcm2 at 750 °C, were obtained.
• The grain grows with the temperature from 50 to 235 nm between 750 and 1050 °C.
• The grain growth above 850 °C causes a significant loss of performance.

La0.8Sr0.2MnO3-δ (LSM) cathodes have been deposited by spray pyrolysis on yttria-stabilized zirconia (YSZ) electrolytes for solid oxide fuel cell (SOFC) applications at intermediate temperatures. The morphology and electrochemical performance of the films have been investigated by scanning electron microscopy and impedance spectroscopy, respectively, in a range of annealing temperatures to evaluate the effect of the heat treatment on the properties. Furthermore, the electrode polarization has been monitored as a function of the oxygen partial pressure to identify the different limiting steps to oxygen reduction reaction. Samples annealed below 850 °C exhibited low values of area specific resistance (ASR), e.g. 0.18 Ωcm2 at 750 °C. The reduction of the triple phase boundary sites due to grain growth above 850 °C causes a significant loss of the cathode performance. The relationship between annealing temperature, morphology and performance of the films has been investigated.

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