Electrical conductivity of Sr{sub 2−x}VMoO{sub 6−y} (x = 0.0, 0.1, 0.2) double perovskites

Journal Article · Fri Jun 28 04:00:00 EDT 2013 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4811715· OSTI ID:22277976

Childs, Nicholas B.; Smith, Richard; Key, Camas ^[1]; Weisenstein, Adam; Sofie, Stephen ^[2]

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1. Department of Physics, EPS 264, Montana State University, Bozeman, Montana 59717 (United States)
2. Department of Mechanical Engineering, Roberts 220, Montana State University, Bozeman, Montana 59717 (United States)

Electrical conductivity of Sr{sub 2-x}VMoO{sub 6-y} (x = 0.0, 0.1, 0.2) double perovskites has been investigated in a reducing atmosphere at temperatures up to 800 °C. This material has a key application in solid oxide fuel cell anodes as a mixed ion and electron conductor. A solid state synthesis technique was used to fabricate materials and crystal structure was verified through x-ray diffraction. Subsequent to conventional sintering in a reducing environment, elemental valence states were indentified through x-ray photoemission spectroscopy on the double perovskite material before and after annealing in a hydrogen environment. Samples exhibited metallic like conduction with electrical conductivities of 1250 S/cm (Sr{sub 2}VMoO{sub 6-y′}), 2530 S/cm (Sr{sub 1.8}VMoO{sub 6-y″}), and 3610 S/cm (Sr{sub 1.9}VMoO{sub 6-y‴}) at 800 °C in 5% H{sub 2}/95% N{sub 2}, with a substantial increase in conductivity upon cooling to room temperature. Room temperature electrical conductivity values for Sr{sub 1.9}VMoO{sub 6-y‴} make it a candidate as the highest electrically conductive oxide known. Highly insulating secondary surface phases, Sr{sub 3}V{sub 2}O{sub 8}, and SrMoO{sub 4}, begin to reduce at 400 °C in a hydrogen environment, as confirmed by X-ray photoemission and thermal gravimetric analysis. This reduction, from V{sup 5+} and Mo{sup 6+} to lower valence states, leads to a large increase in sample electrical conductivity.

• OSTI ID: 22277976
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 24 Vol. 113; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CONCENTRATION RATIO
CRYSTAL STRUCTURE
ELECTRIC CONDUCTIVITY
ELECTRONS
EMISSION SPECTROSCOPY
HYDROGEN
MOLYBDENUM IONS
MOLYBDENUM OXIDES
PEROVSKITE
PHOTOEMISSION
SINTERING
SOLID OXIDE FUEL CELLS
STRONTIUM COMPOUNDS
TEMPERATURE RANGE 0273-0400 K
THERMAL GRAVIMETRIC ANALYSIS
VALENCE
VANADIUM COMPOUNDS
VANADIUM IONS
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY