Carbon Resources Conversion 3 (2020) 112–121 Available online 11 September 2020 2588-9133/© 2020 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Novel materials for solid oxide fuel cells cathodes and oxygen separation membranes: Fundamentals of oxygen transport and performance Vladislav A. Sadykov a, b, * , Ekaterina M. Sadovskaya a, b , Nikita F. Eremeev a , Elena Yu. Pikalova c, d , Nina M. Bogdanovich c , Elena A. Filonova d , Tamara A. Krieger a, b , Yulia E. Fedorova a , Alexey V. Krasnov a, b , Pavel I. Skriabin a , Anton I. Lukashevich a , Robert Steinberger-Wilckens e , Izaak C. Vinke f a Federal Research Center Boreskov Institute of Catalysis SB RAS, 630090 Novosibirsk, Russia b Novosibirsk State University, 630090 Novosibirsk, Russia c Institute of High Temperature Electrochemistry UB RAS, 620137 Yekaterinburg, Russia d Ural Federal University, 620002 Yekaterinburg, Russia e University of Birmingham, Edgbaston, Birmingham B15 2TT, UK f Forschungszentrum Jülich GmbH, 52425 Jülich, Germany A R T I C L E INFO Keywords: Solid oxide fuel cells Oxygen separation membranes Oxygen mobility Perovskites Nanocomposites Ruddlesden – Popper phases ABSTRACT In the feld of modern hydrogen energy, obtaining pure hydrogen and syngas and then being able to use them for green energy production are signifcant problems. Developing solid oxide fuel cells (SOFC) and catalytic mem- branes for oxygen separation as well as materials for these devices is one of the most likely ways to solve these problems. In this work, the authors’ recent studies in this feld are reviewed; the fundamentals of developing materials for SOFC cathodes and oxygen separation membranes’ permselective layers based on research of their oxygen mobility and surface reactivity are presented. Ruddlesden – Popper phases Ln 2–x Ca x NiO 4+δ (LnCNO) and perovskite-fuorite nanocomposites PrNi 0.5 Co 0.5 O 3–δ –Ce 0.9 Y 0.1 O 2–δ (PNC–YDC) were studied by isotope exchange of oxygen with C 18 O 2 and 18 O 2 in fow and closed reactors. For LnCNO a high oxygen mobility was shown (D* ~ 10 –7 cm 2 /s at 700 ◦ C), being provided by the cooperative mechanism of oxygen migration involving both regular and highly-mobile interstitial oxygen. For PNC–YDC dominated a wide fast diffusion channel via fuorite phase and interphases due to features of the redistribution of cations resulting in superior oxygen mobility (D* ~ 10 –8 cm 2 /s at 700 ◦ C). After optimization of composition and nanodomain structure of these materials, as cathodes of SOFC they provided a high power density, while for asymmetric supported oxygen separation membranes – a high oxygen permeability. 1. Introduction Production of syngas and pure hydrogen is a key problem in the feld of modern hydrogen energy. Another related problem is design of de- vices to produce energy from hydrogen, syngas and biofuels which are environmentally friendly. One branch linked to these problems relates to the design of solid oxide fuels cells (SOFC) and catalytic membrane re- actors in general and materials for SOFC cathodes and oxygen separation membranes, or their permselective (functional) layers, in particular. Consequently, mixed ionic-electronic conductors (MIEC) need to be designed for these devices [1–7]. The key characteristics of the materials that affect the performance of these devices are related to oxygen mobility and surface reactivity (oxygen self-diffusion coeffcient and surface exchange constant values) [4–9]. According to Adler – Lane – Steele model, the electrode perfor- mance correlates with the oxygen self-diffusion coeffcient and surface exchange constant values of the material from which the electrode is Abbreviations: EDX, energy-dispersive X-ray spectroscopy analysis; IIE, isothermal isotope exchange; LnCNO, Ln 2x Ca x NiO 4+δ ; LSFC, La 1x Sr x Fe 1y CoyO 3δ ; LSFN, La 1x Sr x Fe 1y NiyO 3δ ; LSM, La 1x Sr x MnO 3δ ; MF, GDC – MnFe 2 O 4 – Ce 0.9 Gd 0.1 O 2δ ; MIEC, mixed ionic- electronic conductor; PNC, PrNi 0.5 Co 0.5 O 3δ ; PNC, YDC – PrNi 0.5 Co 0.5 O 3δ – Ce 0.9 Y 0.1 O 2δ ; RP, Ruddlesden – Popper phases; SOFC, solid oxide fuel cell; TEM, transmission electron microscopy; TPIE, temperature-programmed isotope exchange; XRD, X-ray diffraction; YDC, Ce 0.9 Y 0.1 O 2δ . * Corresponding author at: Federal Research Center Boreskov Institute of Catalysis SB RAS, 630090 Novosibirsk, Russia. E-mail address: sadykov@catalysis.ru (V.A. Sadykov). Contents lists available at ScienceDirect Carbon Resources Conversion journal homepage: www.sciencedirect.com/journal/carbon-resources-conversion https://doi.org/10.1016/j.crcon.2020.08.002 Received 22 May 2020; Received in revised form 3 August 2020; Accepted 30 August 2020