EPR analysis of the local structure of Ni3+ ions in Ni-based electrode materials obtained under high-pressure
- 186 Downloads
X-band and high-frequency EPR spectroscopy was applied to monitor the short-range cation ordering in Ga, Al and Li substituted LiNiO2 with a layered crystal structure. The mixed oxides were obtained by a high-pressure synthesis in an oxygen rich atmosphere. Analysis of the EPR line-width from the X-band experiments together with the values of the g-tensor from the high-frequency EPR experiments permits assesing the local structure of the mixed metal layers. The results obtained show that LiGayNi1−yO2, LiAlyNi1−yO2 and Li1 + xNi1−xO2 are homogeneous solid solutions, whereas the Li1 + xNi1−x−yAlyO2 compositions have rather a complex domain structure of the type (1−a)LiAlyNi1−yO2.aLi[Li1/3Ni2/3]O2.
KeywordsElectron Paramagnetic Resonance Electron Paramagnetic Resonance Spectrum Electron Paramagnetic Resonance Signal Electron Paramagnetic Resonance Spectroscopy Li2TiO3
The authors thank the National Science Fund of Bulgaria (Contract no. Ch1304/2003) for financial support. R.S. and E.Sh. are grateful to the EC for a grant of a EU “Research Infrastructures: Transnational Access” Programme (Contract No. 505320 (RITA) – High Pressure) for performing high-pressure synthesis experiments at the Bayrisches Geoinstitute. The high-frequency EPR measurements carried out at High Magnetic Field Laboraty in Grenoble, France, were supported by the European Commission within the 6th framework programme “Transnational Access - Specific Support Action” (contract No. RITA-CT-2003-505474) – “Access to research in very high magnetic field”. The authors are very grateful to Dr. T. Boffa-Ballaran and Dr. C. McCammon, from Bayerisches Geoinstitut, Universität Bayreuth, and Dr. A.-L. Barra, from High Magnetic Field Laboratory in Grenoble, for their help.
- 3.Alcántara R, Lavela P, Tirado J-L, Zhecheva E, Stoyanova R (1999) J Solid State Electrochem 3:121Google Scholar