Chemical compatibility of solid oxide fuel cell air electrode Pr4Ni3O10±δ with commercial electrolytes

Abstract

AbstractThe chemical reactivity between Pr4Ni3O10±δ (3‐PNO) electrodes and Y0.08Zr0.92O1.96 (YSZ), Ce0.9Gd0.1O1.95 (GDC), and La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) electrolytes was analyzed by electrochemical impedance spectroscopy and X‐ray diffraction. 3‐PNO powders were synthesized by two different chemical routes, one of them uses hexamethylenetetramine (HMTA) as a complexing agent (route A) while the other citrates (route B). The samples observed by scanning electron microscopy presented different microstructures; route A powders present small submicronic grains with an open microstructure while route B powders are formed by larger well‐connected grains. The polarization resistance (RP) values for 3‐PNO/YSZ cells are one order of magnitude higher than those of 3‐PNO/GDC and 3‐PNO/LSGM cells. The RP for both cells 3‐PNO/GDC and 3‐PNO/LSGM and its evolution in time suggest that chemical reactivity takes place during the adhesion treatment and electrochemical measurements. The microstructure plays a crucial role in RP and the degradation rate; 3‐PNO obtained by route A (3‐PNO‐HMTA) exhibits the best electrochemical performance since these powders present a well‐loose morphology and a large exposed area. However, this fact makes them active chemically, so the increase of RP with time is slower for 3‐PNO electrodes prepared by route B (3‐PNO‐Cit), since the rate of chemical reactivity with the electrolyte is slower.