Enhanced proton conductivity and stability of Ba-deficient BaCe0.8Y0.2O3-δ
[EN] A-cation deficiency has a significant impact on the properties of proton-conducting perovskites (ABO), depending on factors such as the ionic radius, concentration of dopant and degree of substoichiometry of the A-site cation. Here, we focus on the influence of Ba deficiency on the structure, s...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2021 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/275110 |
| Acceso en línea: | http://hdl.handle.net/10261/275110 |
| Access Level: | acceso abierto |
| Palabra clave: | A-site substoichiometry Proton transport Partial conductivity Protonic ceramic fuel cell BCY Barium cerate |
| Sumario: | [EN] A-cation deficiency has a significant impact on the properties of proton-conducting perovskites (ABO), depending on factors such as the ionic radius, concentration of dopant and degree of substoichiometry of the A-site cation. Here, we focus on the influence of Ba deficiency on the structure, stability and partial electrical conductivities of the perovskite BaCeYO (BCY20). Neutron powder diffraction is employed to determine a monoclinic symmetry (space group I2/m) for BaCeYO (B95CY20), with greater distortion and specific free volume than BCY20. Confocal Raman microscopy integrated with atomic force microscopy and X-ray diffraction confirm improved resistance to carbonate formation in the Ba-deficient material. Electrical conductivity is also greater for B95CY20 in both wet and dry oxidising and moderate reducing conditions, reaching ≈1.4 and 1 S m in dry conditions of O and N, respectively, at 600 °C. Partial conductivities determined by a defect-chemistry-based method indicate that proton conductivity is dominant in wet air for temperatures <700 °C and greater for B95CY20 (≈0.95 S m at 600 °C) in comparison to BCY20 (≈0.58 S m at 600 °C), with an associated hydration enthalpy of −128 kJ mol. Mixed oxide ionic-electronic conductivity dominates in dry oxidising conditions and, again, is greater for Ba substoichiometric material. |
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