Synthesis and characterisation of vanadium doped alkaline earth lanthanum germanate oxyapatite electrolyte
The crystal chemistry and oxygen conductivity of vanadium-doped apatites of nominal composition [La8AE2][Ge6−xVx]O26+x/2 (AE = Ca, Sr, Ba; 0 ≤ x ≤ 1.5) were studied to establish their potential as intermediate temperature solid oxide fuel cell (SOFC) electrolytes. Single-phase products obtained for...
| Main Authors: | , , , , , , , , |
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| Format: | Journal Article |
| Language: | English |
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2013
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| Online Access: | https://hdl.handle.net/10356/96346 http://hdl.handle.net/10220/11576 |
| _version_ | 1811689490479054848 |
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| author | Li, Henan Baikie, Tom Pramana, Stevin S. Shin, J. Felix Slater, Peter R. Brink, Frank Hester, James Wallwork, Kia White, Timothy John |
| author2 | School of Materials Science & Engineering |
| author_facet | School of Materials Science & Engineering Li, Henan Baikie, Tom Pramana, Stevin S. Shin, J. Felix Slater, Peter R. Brink, Frank Hester, James Wallwork, Kia White, Timothy John |
| author_sort | Li, Henan |
| collection | NTU |
| description | The crystal chemistry and oxygen conductivity of vanadium-doped apatites of nominal composition [La8AE2][Ge6−xVx]O26+x/2 (AE = Ca, Sr, Ba; 0 ≤ x ≤ 1.5) were studied to establish their potential as intermediate temperature solid oxide fuel cell (SOFC) electrolytes. Single-phase products obtained for x ≤ 0.5 were found, using a combination of powder synchrotron X-ray and neutron diffraction, to be P63/m apatites. The ionic conductivities extracted by complex impedance spectroscopy showed that small vanadium amendments enhanced oxygen mobility at intermediate temperatures (500–700 °C) by more than one order of magnitude, as the incorporation of V5+ through displacement of Ge4+ is charge balanced with interstitial O2− that improves ionic conduction. The most promising composition was La7.88Ca2Ge5.35V0.65O26.15 that delivered σ = 3.44 × 10−4 S cm−1 at 500 °C. The superstoichiometric oxygen was delocalised, without fixed X-ray or neutron scattering centres. Crystal chemistry systematics demonstrate that the Ca-apatite was superior because the relatively small framework expanded the tunnel through reduced (La/AE)O6 metaprism twisting (φ), ensuring the P63/m symmetry was adopted, which favours the passage of O2− with lower activation energy. |
| first_indexed | 2024-10-01T05:48:56Z |
| format | Journal Article |
| id | ntu-10356/96346 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T05:48:56Z |
| publishDate | 2013 |
| record_format | dspace |
| spelling | ntu-10356/963462023-07-14T15:54:13Z Synthesis and characterisation of vanadium doped alkaline earth lanthanum germanate oxyapatite electrolyte Li, Henan Baikie, Tom Pramana, Stevin S. Shin, J. Felix Slater, Peter R. Brink, Frank Hester, James Wallwork, Kia White, Timothy John School of Materials Science & Engineering Solid oxide fuel cell Electrolyte Crystal chemistry Microscopic structure Apatite The crystal chemistry and oxygen conductivity of vanadium-doped apatites of nominal composition [La8AE2][Ge6−xVx]O26+x/2 (AE = Ca, Sr, Ba; 0 ≤ x ≤ 1.5) were studied to establish their potential as intermediate temperature solid oxide fuel cell (SOFC) electrolytes. Single-phase products obtained for x ≤ 0.5 were found, using a combination of powder synchrotron X-ray and neutron diffraction, to be P63/m apatites. The ionic conductivities extracted by complex impedance spectroscopy showed that small vanadium amendments enhanced oxygen mobility at intermediate temperatures (500–700 °C) by more than one order of magnitude, as the incorporation of V5+ through displacement of Ge4+ is charge balanced with interstitial O2− that improves ionic conduction. The most promising composition was La7.88Ca2Ge5.35V0.65O26.15 that delivered σ = 3.44 × 10−4 S cm−1 at 500 °C. The superstoichiometric oxygen was delocalised, without fixed X-ray or neutron scattering centres. Crystal chemistry systematics demonstrate that the Ca-apatite was superior because the relatively small framework expanded the tunnel through reduced (La/AE)O6 metaprism twisting (φ), ensuring the P63/m symmetry was adopted, which favours the passage of O2− with lower activation energy. Accepted version 2013-07-16T06:55:36Z 2019-12-06T19:29:21Z 2013-07-16T06:55:36Z 2019-12-06T19:29:21Z 2012 2012 Journal Article Li, H., Baikie, T., Pramana, S. S., Shin, J. F., Slater, P. R., Brink, F., et al. (2012). Synthesis and characterisation of vanadium doped alkaline earth lanthanum germanate oxyapatite electrolyte. Journal of Materials Chemistry, 22(6), 2658-2669. https://hdl.handle.net/10356/96346 http://hdl.handle.net/10220/11576 10.1039/c1jm13752b en Journal of materials chemistry © 2012 The Royal Society of Chemistry. This is the author created version of a work that has been peer reviewed and accepted for publication by Journal of materials chemistry, The Royal Society of Chemistry. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1039/c1jm13752b]. application/pdf |
| spellingShingle | Solid oxide fuel cell Electrolyte Crystal chemistry Microscopic structure Apatite Li, Henan Baikie, Tom Pramana, Stevin S. Shin, J. Felix Slater, Peter R. Brink, Frank Hester, James Wallwork, Kia White, Timothy John Synthesis and characterisation of vanadium doped alkaline earth lanthanum germanate oxyapatite electrolyte |
| title | Synthesis and characterisation of vanadium doped alkaline earth lanthanum germanate oxyapatite electrolyte |
| title_full | Synthesis and characterisation of vanadium doped alkaline earth lanthanum germanate oxyapatite electrolyte |
| title_fullStr | Synthesis and characterisation of vanadium doped alkaline earth lanthanum germanate oxyapatite electrolyte |
| title_full_unstemmed | Synthesis and characterisation of vanadium doped alkaline earth lanthanum germanate oxyapatite electrolyte |
| title_short | Synthesis and characterisation of vanadium doped alkaline earth lanthanum germanate oxyapatite electrolyte |
| title_sort | synthesis and characterisation of vanadium doped alkaline earth lanthanum germanate oxyapatite electrolyte |
| topic | Solid oxide fuel cell Electrolyte Crystal chemistry Microscopic structure Apatite |
| url | https://hdl.handle.net/10356/96346 http://hdl.handle.net/10220/11576 |
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