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Title: Structural, thermal and electrical conductivity characteristics of Ln{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} (Ln: La, Nd and Sm) complex perovskites as anode materials for solid oxide fuel cell

The Ti and Mn replaced complex perovskites, Ln{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} (Ln: La, Nd and Sm), were reported as potential anode materials for high temperature-operating solid oxide fuel cells (HT-SOFCs). For the present research study, synthesis, crystallographic, thermal and electrical conductivity properties of Ln{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} complex perovskites were investigated using X-ray diffraction (XRD), Rietveld method, thermogravimetric analysis (TGA) and electrical conductivity to apply these oxide materials for the HT-SOFC anode materials. XRD results showed that Ln{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} oxide systems synthesized as single phases did not react with 8 mol% yttria stabilized zirconia (8YSZ) and 10 mol% Gd-doped cerium oxide (CGO91) up to 1500 °C and did not decompose under dry 3.9% hydrogen at 850 °C. The crystal structures of La{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} (LSTM), Nd{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} (NSTM) and Sm{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} (SSTM) showed orthorhombic symmetry with the space group Pbnm and SSTM showed a more distorted structure. Thermogravimetric analysis (TGA) proved weight gains in these three sample occurred under oxidizing conditions and weight loss under reducing conditions. Electrical conductivity values of NSTM were higher than those of LSTM and SSTM undermore » oxidizing and reducing conditions. - Graphical abstract: The B-site cations (Ti/Mn) are surrounded by regular octahedra of oxygen in Nd{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d}(NSTM). These octahedra are linked together in a corner sharing three dimensional framework, while Nd/Sr ion occupies 12-coordinated A-site between these octahedra. The Ti/Mn–O{sub 6} octahedra are elongated along the c-axis. The crystal structure distortion was due to the smaller ionic radius of the A-site cations, which force the (Ti/Mn)–O{sub 6} octahedra to tilt in order to optimize the A–O bond distances. The same structural symmetry was found when the samples were reduced in 3.9% H{sub 2} in Ar at 900 °C for 12 h. - Highlights: • Ln{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d} oxide systems do not react with 8YSZ and CGO91. • LSTM, NSTM and SSTM show orthorhombic symmetry with the space group Pbnm. • LSTM shows relatively lower onset temperature in Ln{sub 0.5}Sr{sub 0.5}Ti{sub 0.5}Mn{sub 0.5}O{sub 3±d}. • Electrical conductivity values of NSTM are higher than those of LSTM and SSTM.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [5]
  1. Fuel Cell Research Center, Korea Institute of Science and Technology (KIST), 5, Hwarang-Ro 14-Gil, Seongbuk-Gu, Seoul 136-791 (Korea, Republic of)
  2. (United States)
  3. Faculty of Integrated Technologies, University Brunei Darussalam, Jalan Tunku Link, Gadong, BE 1410 (Brunei Darussalam)
  4. School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 9ST (United Kingdom)
  5. Department of Applied Materials Science and Engineering, Hanbat National University, 125, Dongseo-Daero, Yuseong-Gu, Daejeon 305-719 (Korea, Republic of)
  6. Center for Energy Materials Metrology, Division of Industrial Metrology, Korea Research Institute of Standards and Science (KRISS), 267 Gajeong-Ro, Yuseong-Gu, Daejeon 305-340 (Korea, Republic of)
  7. Department of Engine Research, Korea Institute of Machinery and Materials (KIMM), Daejeon 305-343 (Korea, Republic of)
  8. Department of Electrical Engineering, Hanbat National University, 125, Dongseo-Daero, Yuseong-Gu, Daejeon 305-719 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22475649
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 226; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BOND LENGTHS; CERIUM OXIDES; DOPED MATERIALS; ELECTRIC CONDUCTIVITY; HYDROGEN; LANTHANUM COMPOUNDS; MANGANATES; NEODYMIUM COMPOUNDS; ORTHORHOMBIC LATTICES; SAMARIUM COMPOUNDS; SOLID OXIDE FUEL CELLS; STRONTIUM COMPOUNDS; SYNTHESIS; THERMAL GRAVIMETRIC ANALYSIS; TITANIUM COMPOUNDS; X-RAY DIFFRACTION; YTTRIUM OXIDES; ZIRCONIUM OXIDES