Computational Investigation of the Potential SOFC Air Electrode YSr₂Cu₂FeO_8-Δ

YBaCuO-type oxides of the YSr 2 Cu 2 MO 8-δ (M = Co, Fe) systems were previously studied as air electrodes for SOFCs 1 and more recently have attracted great attention due to the electrocatalitic properties reported on YSr 2 Cu 2 FeO 8-δ 2 and La 1.5 Ba 1.5 Cu 3 O 7± δ . 3 The compound YSr 2 Cu 2 FeO 7.56 is a p -type semiconductor, mixed valence Fe 3+ /Fe 4+ and Cu 2+ /Cu 3+ oxide, which exhibits an interesting electrochemical behavior associated to catalytic activity in the oxygen reduction reaction (ORR), being a potential air-electrode for solid oxide fuel cells (SOFCs) 2 . In this contribution we present a computational study of the YSr 2 Cu 2 FeO 8-δ (0< δ <1) system. We have firstly evaluated the performance of the generalized gradient approximation (GGA), the strongly constrained and appropriately normed (SCAN), and their Hubbard U corrections, GGA+ U and SCAN+ U , to reproduce the crystal and electronic crystal structures of YSr 2 Cu 2 FeO 8-δ with δ = 0, 0.5 and 1. . The results validate the SCAN functional for the reliable investigation of these compounds. Further, the position of the oxygen electronic 2 p band center is discussed as descriptor for the catalytic activity of these oxides. J. E. H. Sansom, E. Kendrick, H. A. Rudge-Pickard, M. S. Islam, A. J. Wright and P. R. Slater, Journal of Materials Chemistry , 2005, 15 , 2321-2327. S. A. Lopez-Paz, R. Marin-Gamero, X. Martinez de Irujo-Labalde, J. Sanchez-Marcos, D. Perez-Coll, M. A. A. y. Franco and S. Garcia-Martin, Journal of Materials Chemistry A , 2021, 9 , 8554-8560. A. N. Keyun Li, K. Świerczek, A. Stępień, Y. Naumovich, J.Dąbrowa, M. Zajusz, K. Zheng, B. Dabrowski, Journal of Power Sources , 2022, 532 , 231371.