Conductivity of reduced La{sub 2}Mo{sub 2}O{sub 9} based oxides: The effect of tungsten substitution
- Laboratoire d'Electrochimie et de Physico-chimie des Materiaux et des Interfaces, UMR CNRS 5631, ENSEEG BP75, 38402 Saint Martin d'Heres Cedex (France)
The electrical properties of reduced LAMOX-type oxides (La{sub 1.9}Y{sub 0.1}Mo{sub 2-y}W {sub y}O{sub 9-{delta}} with y = 0, y = 0.5, y = 1.0) were investigated by complex impedance spectroscopy. When reduced at 605 deg. C in hydrogen, La{sub 1.9}Y{sub 0.1}Mo{sub 2}O{sub 9-{delta}} is 10 times and 3 x 10{sup 5} times more conductive at 605 and 180 deg. C, respectively, than in air at the same temperatures. The conductivity curve presents a low slope (0.37 eV versus 1.2 eV in air). Besides, the stabilising effect of tungsten against reduction is evidenced, in good agreement with previous reports. In low oxygen partial pressures however (PO{sub 2} < 10{sup -18} Pa), the decomposition of the materials is detected, whatever the tungsten content (0 {<=} y {<=} 1 in La{sub 1.9}Y{sub 0.1}Mo{sub 2-y}W {sub y}O{sub 9-{delta}}). This observation points out the efficiency limit of Mo{sup 6+}/W{sup 6+} substitution to stabilise the structure against reduction, and the limit for an application as IT-SOFC electrolyte. However, given the high electronic conductivity upon reduction, the application of these materials in IT-SOFC electrodes could be considered.
- OSTI ID:
- 21000639
- Journal Information:
- Materials Research Bulletin, Vol. 42, Issue 5; Other Information: DOI: 10.1016/j.materresbull.2006.08.012; PII: S0025-5408(06)00344-8; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
Similar Records
Reducibility study of oxide-ion conductors La{sub 2-x}Ba{sub x}Mo{sub 2-y}A{sub y}O{sub 9-{delta}} (A = W, Al, Ga) assessed by impedance spectroscopy
Comprehensive survey of Nd{sup 3+} substitution In La{sub 2}Mo{sub 2}O{sub 9} oxide-ion conductor