Structure and properties of ordered Li2IrO3 and Li2PtO3
| Autor: | Henk Verweij, Matthew J. O'Malley, Patrick M. Woodward |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Band gap
Stereochemistry chemistry.chemical_element Electronic structure Crystal structure Condensed Matter Physics Electronic Optical and Magnetic Materials Inorganic Chemistry Crystallography Transition metal chemistry X-ray crystallography Materials Chemistry Ceramics and Composites Lithium Physical and Theoretical Chemistry Electronic band structure Monoclinic crystal system |
| Zdroj: | Journal of Solid State Chemistry. 181:1803-1809 |
| ISSN: | 0022-4596 |
| Popis: | The structures of Li 2 M O 3 ( M =Ir, Pt) can be derived from the well-known Li-ion battery cathode material, LiCoO 2 , through ordering of Li + and M 4+ ions in the layers that are exclusively occupied by cobalt in LiCoO 2 . The additional cation ordering lowers the symmetry from rhombohedral ( R -3 m ) to monoclinic ( C 2/ m ). Unlike Li 2 RuO 3 no evidence is found for a further distortion of the structure driven by formation of metal–metal bonds. Thermal analysis studies coupled with both ex-situ and in-situ X-ray diffraction measurements show that these compounds are stable up to temperatures approaching 1375 K in O 2 , N 2 , and air, but decompose at much lower temperatures in forming gas (5% H 2 :95% N 2 ) due to reduction of the transition metal to its elemental form. Li 2 IrO 3 undergoes a slightly more complicated decomposition in reducing atmospheres, which appears to involve loss of oxygen prior to collapse of the layered Li 2 IrO 3 structure. Electrical measurements, UV–visible reflectance spectroscopy and electronic band structure calculations show that Li 2 IrO 3 is metallic, while Li 2 PtO 3 is a semiconductor, with a band gap of 2.3 eV. |
| Databáze: | OpenAIRE |
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