Preparation, structure, and thermal stability of new NixCo1-2xMnx(OH)2 (0≤x≤1/2) phases

The preparation, characterization, and thermal stability of NixCo1-2xMnx(OH)(2) (0 less than or equal to x less than or equal to 1/2) is reported. These hydroxides are prepared by coprecipitation as the first step in the preparation of the corresponding Li[NixCo(1-2x)Mnx]O-2 (0 less than or equal to x less than or equal to 1/2) oxides. Precipitates dried at room temperature adopt the hexagonal CdI2 structure. Thermal studies show that the hexagonal CdI2 type (RT) structure transforms to a cubic spinel-type solid solution (NixCo(1-2x)Mnx](3)O-4 (0 less than or equal to x less than or equal to 3/8) above about 150 degreesC that becomes well-crystallized at 600 degreesC. An intermediate turbostratic structure phase occurs between room temperature and 150 degreesC. This phase is present in small amounts in room-temperature-dried NixCo1-2xMnx(OH)(2) materials with x greater than or equal to 3/8. The results show that the drying method of the precipitate induces different phases with different bulk and tap density. This could have a major influence on the morphology, composition, density, and cell performance of Li[NixCo(1-2x)Mnx]O-2 (0 less than or equal to x less than or equal to 1/2) oxides obtained from these dried precipitates.