| Ruddlesden-Popper-type Nd2-xNi0.75Cu0.2M0.05O4±δ (x = 0 and 0.1; M = Ga, Sc and In) layered oxides as candidate materials for MIEC-type ceramic membranes Konrad Swierczek1; Anna Niemczyk1; Anna Olszewska1; Zijia Zhang2; Hailei Zhao2; Kacper Cichy3; 1AGH UNIVERSITY OF SCIENCE AND TECHNOLOGY, FACULTY OF ENERGY AND FUELS, Krakow, Poland; 2UNIVERSITY OF SCIENCE AND TECHNOLOGY BEIJING, SCHOOL OF MATERIALS SCIENCE AND ENGINEERING, Beijing, China; 3AGH UNIVERSITY OF SCIENCE AND TECHNOLOGY, Krakow, Poland; PAPER: 138/AdvancedMaterials/Regular (Oral) SCHEDULED: 15:55/Tue. 29 Nov. 2022/Saitong ABSTRACT: Ceramic membranes, due to their high permeability, ability to work in the aggressive environment, including high temperature and high pressure, chemical and mechanical stability seem to be promising substitution compared to the commonly used polymeric membranes. Despite their higher investment cost, in relation to the organic membranes, ceramic gas separators are more economically favourable in long term perspective (slower degradation) [1,2] Similarly to Solid Oxide Fuel Cells (SOFCs) and Solid Oxide Electrolyzer Cells (SOECs), membrane technologies are considered as one of the basic solution in so-called Grand Energy Transmission [3-5]. Ruddlesden-Popper-type (RP) oxides usually possess mixed ionic-electronic conductivity, which is a crucial requirement for the effectively-working ceramic membranes. Ionic transport in the considered group of materials might be realized by the vacancy mechanism (in the perovskite-type layer) or by rather unusual interstitial mechanism employing interstitial oxygen. In this work RP Nd<sub>2-x</sub>Ni<sub>0.75</sub>Cu<sub>0.2</sub>M<sub>0.05</sub>O<sub>4±δ</sub> (x = 0 and 0.1; M = Ga, Sc and In) oxides were obtained by a sol-gel route and characterized concerning phase composition and crystal structure. Among the materials, Nd<sub>2-x</sub>Ni<sub>0.75</sub>Cu<sub>0.2</sub>Ga<sub>0.05</sub>O<sub>4±δ</sub> (x = 0; 0.1) were selected, with systematic characterization of the crystal structure at high temperatures, oxygen content, as well as transport properties measured. It is shown that the Nd-site deficiency causes decrease of the oxygen content, which at high temperatures leads to a change of the dominant type of defects from the oxygen interstitials to the vacancies. Importantly, both examined Ga-containing materials exhibit full chemical stability in CO<sub>2</sub> atmosphere, which makes them good candidates for air separation technology. Ceramic membranes manufactured using Nd<sub>2</sub>Ni<sub>0.75</sub>Cu<sub>0.2</sub>Ga<sub>0.05</sub>O<sub>4±δ</sub> and Nd<sub>1.9</sub>Ni<sub>0.75</sub>Cu<sub>0.2</sub>Ga<sub>0.05</sub>O<sub>4±δ</sub> fine powders allowed to obtain very high oxygen fluxes equal to 0.69 mL cm<sup>-2</sup> min<sup>-1</sup> and 0.78 mL cm<sup>-2</sup> min<sup>-1</sup> at ca. 880 °C, respectively for 0.9 mm thick pellets. Moreover, it is shown for Nd<sub>2</sub>Ni<sub>0.75</sub>Cu<sub>0.2</sub>Ga<sub>0.05</sub>O<sub>4±δ</sub>-based pellet that infiltration of the grains with the higher order RP oxide (e.g. La<sub>4</sub>Ni<sub>3</sub>O<sub>10</sub>) combined with reduced thickness of the membrane allows to maximize oxygen flux values, with one of the highest reported oxygen fluxes measured for CO<sub>2</sub>-stable RP-based ceramic membrane, i.e. 0.94 mL cm<sup>-2</sup> min<sup>-1</sup> at ca. 880 °C for 0.6 mm thick dense membrane. References: [1] J. Garcia-Fayos, J. M. Serra, M. W. J. Luiten-Olieman and W. A. Meulenberg, Gas separation ceramic membranes. Advanced Ceramics for Energy Conversion and Storage, Elsevier 2020 [2] H. A. Meinema, R. W. J. Dirrix, H. W. Brinkman, R. A. Terpstra, J. Jekerle and P. H. Kösters, InterCeram Int. Ceram. Rev., 2005, 54, 86-91 [3] A. Fargere, B. Kolodziejczyk, J. Carton, L. Lapeña Martinez, A. Pica Téllez, C. Karaca, Y. Chae and L. Fuselli, Hydrogen an enabler of the Grand Transition, 2018 [4] I. Staffell, D. Scamman, A. Velazquez Abad, P. Balcombe, P. E. Dodds, P. Ekins, N. Shah and K. R. Ward, Energy Environ. Sci., 2019, 12, 463-491 [5] M. Gotz, J. Lefebvre, F. Mors, A. McDaniem Koch, S. Bajohr, R. Reimert and T. Kolb, Renewable Energy, 2016, 85, 1371-1390 |
