The Li Ni0.2Mn0.2Co0.6O2 electrode materials: A structural and magnetic study
| Autor: | Ismael Saadoune, Mohamed Labrini, Pedro Amorós, A. Almaggoussi, Jamal Elhaskouri |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Electrode material
Materials science Mechanical Engineering Analytical chemistry chemistry.chemical_element Condensed Matter Physics Magnetic susceptibility Ion law.invention Paramagnetism chemistry Mechanics of Materials law Phase (matter) General Materials Science Lithium Electron paramagnetic resonance Solid solution |
| Zdroj: | Materials Research Bulletin. 47:1004-1009 |
| ISSN: | 0025-5408 |
| DOI: | 10.1016/j.materresbull.2012.01.008 |
| Popis: | Graphical abstract: EPR signal of the Li{sub 0.6}Co{sub 0.6}Ni{sub 0.2}Mn{sub 0.2}O{sub 2} composition showing that Mn{sup 4+} ions are the solely paramagnetic ions in the structure. Highlights: Black-Right-Pointing-Pointer LiCo{sub 0.6}Ni{sub 0.2}Mn{sub 0.2}O{sub 2} was prepared by the combustion method with sucrose as a fuel. Black-Right-Pointing-Pointer Chemical delithiaition was performed by using NO{sub 2}BF{sub 4} oxidizing agent. Black-Right-Pointing-Pointer The rhombohedral symmetry was preserved upon lithium removal. Black-Right-Pointing-Pointer Lithium extraction leads to Ni{sup 2+} oxidation to Ni{sup 4+} followed by Co{sup 3+} oxidation. Black-Right-Pointing-Pointer The EPR narrow signal of Li{sub 0.6}Co{sub 0.6}Ni{sub 0.2}Mn{sub 0.2}O{sub 2} is due to the only active Mn{sup 4+} ions. -- Abstract: Layered LiNi{sub 0.2}Mn{sub 0.2}Co{sub 0.6}O{sub 2} phase, belonging to a solid solution between LiNi{sub 1/2}Mn{sub 1/2}O{sub 2} and LiCoO{sub 2} most commercialized cathodes, was prepared via the combustion method at 900 Degree-Sign C for a short time (1 h). Structural and magnetic properties of this material during chemical extraction were investigated. The powders adopted the {alpha}-NaFeO{sub 2} structure with almost none of the well-known Li/Ni cation disorder. The analysis of the magnetic properties in the paramagnetic domain agrees with the combination of Ni{sup 2+} (S = 1), Co{sup 3+} (S = 0) and Mn{sup 4+} (Smore » = 3/2) spin-only values. X-ray analysis of the chemically delithiated Li{sub y}Ni{sub 0.2}Mn{sub 0.2}Co{sub 0.6}O{sub 2} reveals no structural transition. The process of lithium extraction from and insertion into LiNi{sub 0.2}Mn{sub 0.2}Co{sub 0.6}O{sub 2} was discussed on the basis of ex situ EPR experiments and magnetic susceptibility. Oxidation of Ni{sup 2+} (S = 1) to Ni{sup 3+} (S = 1/2) and to Ni{sup 4+} (S = 0) was observed upon lithium removal.« less |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect