The A-cation deficient perovskite series La sub(2-x)CoTiO sub(6- delta ) (0 less than or equal to x less than or equal to 0.20): new components for potential SOFC composite cathodes

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2016-02, Vol.4 (9), p.3386-3397
• Main Authors: Gomez-Perez, Alejandro, Azcondo, MTeresa, Yuste, Mercedes, Perez-Flores, Juan Carlos, Bonanos, Nikolaos, Porcher, Florence, Munoz-Noval, Alvaro, Hoelzel, Markus, Garcia-Alvarado, Flaviano, Amador, Ulises
• Format: Article
• Language: English
• Subjects: Cathodes; Defects; Deposition; Electrolytes; Order disorder; Perovskites; Solid oxide fuel cells; Vacancies
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c5ta08025h

La sub(2-x)CoTiO sub(6- delta )/Ce sub(0.9)Gd sub(0.1)O sub(2- delta ) composites are presented as promising new cathodes for solid oxide fuel cells. The B-site ordering characteristic of double perovskites is present in the whole series. Additionally, increasing amounts of La-vacancies give rise to ordering of alternating La-rich and [squ-rich ([squ = vacancy) layers perpendicular to the c-axis. The introduction of La vacancies produces both oxidation of Co super(2+) to Co super(3+) and oxygen vacancies inducing a change of both electrical and electrochemical properties. The best electrochemical performances are obtained for low x due to a compromise between sufficiently high amount of defects to provide electronic and ionic conductivities, but not so high to induce defect clustering. The material with x= 0.05 exhibits the best performances of the series. Symmetrical cells made of composites of this material and Ce sub(0.9)Gd sub(0.1)O sub(2- delta ) deposited on pellets of this electrolyte show a polarization resistance of 0.39 Omega cm super(2) at 1073 K.