Preparation by a ‘chimie douce’ route and characterization of (LiNi z Mn 1 –z O 2 )(0.5⩽z⩽1) cathode materials
1996; Royal Society of Chemistry; Volume: 6; Issue: 7 Linguagem: Inglês
10.1039/jm9960601149
ISSN1364-5501
AutoresDaniel Caurant, Noël Baffler, V. Bianchi, Gilles Grégoire, S. Bach,
Tópico(s)Ferroelectric and Piezoelectric Materials
ResumoLiNizMn1 –zO2 cathode materials have been prepared using a ‘chimie douce’ route for 0.5 ⩽z⩽1 Coprecipitation of hydroxides is followed by drying and heating at 700 °C for 5 h under oxygen flow. Because of the high reactivity of the coprecipitates, the preparation time is shorter than for the classical powder mixing and heating methods used generally, and materials with 0.5⩽z⩽1 are obtained easily. DTA-TG and XRD studies have been performed for each composition. The LiNizMn1 –zO2 crystallinity deteriorates progressively when the manganese content is increased, but in contrast to the pure LiNiO2 compound, partial manganese substitution removes the lithium deficiency. Moreover, owing to the ease of oxidation of manganese ions, partially substituted compounds can be obtained at lower temperature than for pure LiNiO2. However, manganese substitution in LiNiO2 deteriorates the electrochemical capacity and reversibility of this compound. This is probably due to the large difference between the structures of nickel and manganese lithium oxides, which produces increasing disorder between layers when the Mn content is increased.
Referência(s)