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Abstract
Apatite-type oxide-ion conductors have attracted considerable interest as potential fuel cell electrolytes. Atomistic modelling techniques have been used to investigate oxygen interstitial sites, protonic defects and water incorporation in three silicate and three germanate-based apatite-systems, namely La8Ba2(SiO4)(6)O-2, La-9.33(SiO4)(6)O-2, La-9.67(SiO4)(6)O-2.5, La8Ba2(GeO4)(6)O-2, La-9.33(GeO4)(6)O-2, and La-9.67(GeO4)(6)O-2.5. The simulation models reproduce the complex experimental structures for all of these systems. The interstitial defect simulations have examined the lowest energy configuration and confirm this site to be near the Si/GeO4 tetrahedra. The water incorporation calculations identify the O-H protonic site to be along the O-4 oxygen channel as seen in naturally occurring hydroxy-apatites. The results also show more favourable and exothermic water incorporation energies for the germanate based apatites. This is consistent with recent experimental work, which shows that Ge-apatites take up water more readily than the silicate analogues.
Original language | English |
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Pages (from-to) | 2766-2772 |
Number of pages | 7 |
Journal | Journal of Materials Chemistry |
Volume | 20 |
Issue number | 14 |
DOIs | |
Publication status | Published - 18 Feb 2010 |
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Dive into the research topics of 'Protonic defects and water incorporation in Si and Ge-based apatite ionic conductors'. Together they form a unique fingerprint.Projects
- 1 Finished
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Interdisciplinary Studies to Characterise and Optimise Novel Apatite-Type Fast-Ion Conductors
Engineering & Physical Science Research Council
8/01/09 → 7/02/10
Project: Research Councils