SrCo0.85Fe0.15O2.62 -Oxygen deficient "314-type" perovskite; a highly efficient cathode for solid oxide fuel cells

Sourav Marik (1) , Clément Nicollet (1) , Madhu Channabasappa (1) , Sébastien Fourcade (1) , Alain Wattiaux (1) , Mathieu Duttine (1) , Rodolphe Decourt (1) , Jean-Marc. Bassat (1) , Olivier Toulemonde (1)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

Structure, electrical conductivity and electrochemical performance for a new oxygen deficient perovskite material with composition SrCo0.85Fe0.15O2.62 is explored here. It crystallizes in a " 314-type " oxygen-vacancy ordered structure (Space Group: I4/mmm) with 2ap × 2ap × 4ap unit cell, and contains alternate oxygen replete [Co2/Fe2-O] and oxygen deficient [Co1/Fe1-O] planes along c-direction. Room temperature Mössbauer spectroscopy and room temperature neutron powder diffraction confirm the presence of mixed valence states (3+ and 4+) for both Fe and Co. Polaronic behavior in the electrical conductivity is observed below 400 °C, and attributed to the presence of Co 4+ and Fe 3+ cations in the structure. The electrical conductivity at 600 °C is high enough (∼200 S cm −1) to act as a cathode material. At the same time, the polarization resistance measurements show an excellent value of 0.1 Ω cm 2 at 600 °C. These results suggest that at 600 °C, this material is a mixed oxide-ion and electronic conductor exhibiting excellent activity for the oxygen reduction reaction, making it a promising cathode material for an intermediate temperature solid oxide fuel cell.

Domaines: Matériaux

Sourav Marik, Clément Nicollet, Madhu Channabasappa, Sébastien Fourcade, Alain Wattiaux, et al.. SrCo0.85Fe0.15O2.62 -Oxygen deficient "314-type" perovskite; a highly efficient cathode for solid oxide fuel cells. Fuel Cells, 2017, 17 (3), pp.353-358. ⟨10.1002/fuce.201600203⟩. ⟨hal-01545868⟩