Structure and properties of ordered Li2IrO3 and Li2PtO3 |
| |
Authors: | Matthew J. O&rsquo Malley,Henk Verweij |
| |
Affiliation: | a Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210-1185, USA b Department of Materials Science and Engineering, The Ohio State University, 477 Watts Hall, 2041 College Road, Columbus, OH 43210-1124, USA |
| |
Abstract: | The structures of Li2MO3 (M=Ir, Pt) can be derived from the well-known Li-ion battery cathode material, LiCoO2, through ordering of Li+ and M4+ ions in the layers that are exclusively occupied by cobalt in LiCoO2. The additional cation ordering lowers the symmetry from rhombohedral (R-3m) to monoclinic (C2/m). Unlike Li2RuO3 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 O2, N2, and air, but decompose at much lower temperatures in forming gas (5% H2:95% N2) due to reduction of the transition metal to its elemental form. Li2IrO3 undergoes a slightly more complicated decomposition in reducing atmospheres, which appears to involve loss of oxygen prior to collapse of the layered Li2IrO3 structure. Electrical measurements, UV-visible reflectance spectroscopy and electronic band structure calculations show that Li2IrO3 is metallic, while Li2PtO3 is a semiconductor, with a band gap of 2.3 eV. |
| |
Keywords: | Ordered rock salt pH sensors Metal oxides Platinum group metal oxides Lithium ion X-ray diffraction Faulting |
本文献已被 ScienceDirect 等数据库收录! |
|