Y doping of BaZrO3 may lead to optimum conditions for proton conduction at operating temperature of solid oxide fuel cells: a first principles study
First-principle calculations are performed to investigate Y substitutional defects at ground state and at 1000 K, for Ba- and Zr-rich chemical environments. In dependence on the Fermi level, at ground state singly positively charged Y may be potentially stable on Ba site ( ${{\rm{Y}}}_{Ba}^{1+}$ ) a...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | Materials Research Express |
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| Online Access: | https://doi.org/10.1088/2053-1591/acd98e |
| _version_ | 1797746511129346048 |
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| author | N Raja D Murali S V M Satyanarayana M Posselt |
| author_facet | N Raja D Murali S V M Satyanarayana M Posselt |
| author_sort | N Raja |
| collection | DOAJ |
| description | First-principle calculations are performed to investigate Y substitutional defects at ground state and at 1000 K, for Ba- and Zr-rich chemical environments. In dependence on the Fermi level, at ground state singly positively charged Y may be potentially stable on Ba site ( ${{\rm{Y}}}_{Ba}^{1+}$ ) and neutral as well as singly negatively charged Y on Zr site ( ${\,{\rm{Y}}}_{Zr}^{0}$ and ${{\rm{Y}}}_{Zr}^{1-}$ ). However, using recent results for the doubly positively charged oxygen vacancy ( ${{\rm{V}}}_{{\rm{O}}}^{2+}$ ) and taking account charge compensation, Fermi level pinning occurs, so that under Ba-rich conditions ${{\rm{Y}}}_{{\rm{Zr}}}^{1-}\,$ and ${{\rm{V}}}_{{\rm{O}}}^{2+}$ are really stable. A similar consideration yields ${{\rm{Y}}}_{{\rm{Ba}}}^{1+}$ and ${{\rm{Y}}}_{{\rm{Zr}}}^{1-}$ as stable defects in the Zr-rich case. Concerning ${{\rm{V}}}_{{\rm{O}}}^{2+},$ which occurrence is a prerequisite to obtain a good proton conductor, by Y doping, at ground state only in the Ba-rich case a moderate concentration can be formed. At 1000 K the situation is improved importantly. The consideration of vibrational contributions to the free formation energy of Y on Zr site shows an increase of the stability of ${\,{\rm{Y}}}_{{\rm{Zr}}}^{0}$ and ${{\rm{Y}}}_{{\rm{Zr}}}^{1-}.$ Under Ba-rich conditions Fermi level pinning results in a free formation energy for the doubly positively charged O vacancy of 0.481 eV which corresponds to a high ${{\rm{V}}}_{{\rm{O}}}^{2+}$ concentration and optimum conditions for proton conduction. In Zr-rich case the respective value is 0.863 eV which leads also to relatively high ${{\rm{V}}}_{{\rm{O}}}^{2+}\,$ occurrence but the situation is less favourable than for the Ba-rich environment. |
| first_indexed | 2024-03-12T15:38:49Z |
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| id | doaj.art-fb5ae94ef19d4972be8f88a1e200316d |
| institution | Directory Open Access Journal |
| issn | 2053-1591 |
| language | English |
| last_indexed | 2024-03-12T15:38:49Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
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| series | Materials Research Express |
| spelling | doaj.art-fb5ae94ef19d4972be8f88a1e200316d2023-08-09T16:07:26ZengIOP PublishingMaterials Research Express2053-15912023-01-0110606550410.1088/2053-1591/acd98eY doping of BaZrO3 may lead to optimum conditions for proton conduction at operating temperature of solid oxide fuel cells: a first principles studyN Raja0https://orcid.org/0000-0002-9398-2255D Murali1S V M Satyanarayana2https://orcid.org/0000-0003-2786-8427M Posselt3https://orcid.org/0000-0002-8218-5744The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, IndiaIndian Institute of Information Technology Design and Manufacturing, Kurnool, Andhra Pradesh 518002, IndiaDepartment of Physics, Pondicherry University , Puducherry 605 014, IndiaHelmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstraβe 400, 01328 Dresden, GermanyFirst-principle calculations are performed to investigate Y substitutional defects at ground state and at 1000 K, for Ba- and Zr-rich chemical environments. In dependence on the Fermi level, at ground state singly positively charged Y may be potentially stable on Ba site ( ${{\rm{Y}}}_{Ba}^{1+}$ ) and neutral as well as singly negatively charged Y on Zr site ( ${\,{\rm{Y}}}_{Zr}^{0}$ and ${{\rm{Y}}}_{Zr}^{1-}$ ). However, using recent results for the doubly positively charged oxygen vacancy ( ${{\rm{V}}}_{{\rm{O}}}^{2+}$ ) and taking account charge compensation, Fermi level pinning occurs, so that under Ba-rich conditions ${{\rm{Y}}}_{{\rm{Zr}}}^{1-}\,$ and ${{\rm{V}}}_{{\rm{O}}}^{2+}$ are really stable. A similar consideration yields ${{\rm{Y}}}_{{\rm{Ba}}}^{1+}$ and ${{\rm{Y}}}_{{\rm{Zr}}}^{1-}$ as stable defects in the Zr-rich case. Concerning ${{\rm{V}}}_{{\rm{O}}}^{2+},$ which occurrence is a prerequisite to obtain a good proton conductor, by Y doping, at ground state only in the Ba-rich case a moderate concentration can be formed. At 1000 K the situation is improved importantly. The consideration of vibrational contributions to the free formation energy of Y on Zr site shows an increase of the stability of ${\,{\rm{Y}}}_{{\rm{Zr}}}^{0}$ and ${{\rm{Y}}}_{{\rm{Zr}}}^{1-}.$ Under Ba-rich conditions Fermi level pinning results in a free formation energy for the doubly positively charged O vacancy of 0.481 eV which corresponds to a high ${{\rm{V}}}_{{\rm{O}}}^{2+}$ concentration and optimum conditions for proton conduction. In Zr-rich case the respective value is 0.863 eV which leads also to relatively high ${{\rm{V}}}_{{\rm{O}}}^{2+}\,$ occurrence but the situation is less favourable than for the Ba-rich environment.https://doi.org/10.1088/2053-1591/acd98edensity functional theoryab initio thermodynamicsphonon calculationssolid oxide fuel cells |
| spellingShingle | N Raja D Murali S V M Satyanarayana M Posselt Y doping of BaZrO3 may lead to optimum conditions for proton conduction at operating temperature of solid oxide fuel cells: a first principles study Materials Research Express density functional theory ab initio thermodynamics phonon calculations solid oxide fuel cells |
| title | Y doping of BaZrO3 may lead to optimum conditions for proton conduction at operating temperature of solid oxide fuel cells: a first principles study |
| title_full | Y doping of BaZrO3 may lead to optimum conditions for proton conduction at operating temperature of solid oxide fuel cells: a first principles study |
| title_fullStr | Y doping of BaZrO3 may lead to optimum conditions for proton conduction at operating temperature of solid oxide fuel cells: a first principles study |
| title_full_unstemmed | Y doping of BaZrO3 may lead to optimum conditions for proton conduction at operating temperature of solid oxide fuel cells: a first principles study |
| title_short | Y doping of BaZrO3 may lead to optimum conditions for proton conduction at operating temperature of solid oxide fuel cells: a first principles study |
| title_sort | y doping of bazro3 may lead to optimum conditions for proton conduction at operating temperature of solid oxide fuel cells a first principles study |
| topic | density functional theory ab initio thermodynamics phonon calculations solid oxide fuel cells |
| url | https://doi.org/10.1088/2053-1591/acd98e |
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