Bulk-phase doped manganous-manganic oxide as well as preparation method and application thereof

Abstract

The invention discloses bulk-phase doped manganous-manganic oxide. The bulk-phase doped manganous-manganic oxide is doped with at least one element of yttrium, ytterbium, lanthanum and niobium, wherein the doping amount of the doping element is 0.1%-1.0%, the particle size D50 of manganous-manganic oxide is 3-20 microns, and the tap density is greater than or equal to 1.5 g / cm<3>. The preparationmethod comprises the steps: under a stirring condition, continuously adding a divalent manganese salt and a soluble doped salt solution and ammonia water into a reactor to carry out a coprecipitationreaction, and adding an oxidant to carry out oxidation treatment, so as to obtain the bulk-phase doped manganous-manganic oxide. The manganous-manganic oxide or the manganous-manganic oxide prepared by the preparation method is used as a precursor and mixed with a lithium source, and the mixture is roasted to obtain a lithium ion battery positive electrode material lithium manganate. In the manganous-manganic oxide disclosed by the invention, the doping elements are in uniform bulk phase distribution in microcosmic particles, so that the gram volume of lithium manganate can be improved, the compaction density of the lithium manganate can be improved, and the high-temperature performance and the cycle performance of a lithium manganate product can be remarkably improved.

Description

technical field [0001] The invention belongs to the field of positive electrode materials for lithium ion batteries, and relates to a bulk doped trimanganese tetroxide and a preparation method and application thereof. Background technique [0002] Lithium manganese oxide has a wide application space in lithium-ion batteries, especially small power batteries and energy storage products, due to its rich manganese resources, low price, good safety performance, low temperature and excellent rate performance. [0003] The preparation method of lithium manganate is generally prepared by using electrolytic manganese dioxide (EMD) as the manganese source and lithium carbonate as the lithium source, after mixing, roasting at a high temperature of 700-800°C. [0004] In recent years, the capacity, cycle life, high temperature performance, and safety performance of lithium manganese oxide prepared by using trimanganese tetroxide (MMO) as a manganese source have been significantly impro...

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Problems solved by technology

However, most of the existing technologies adopt mechanical mixing methods, that is, when synthesizing lithium manganate, MMO is mechanically mixed with lithium sources and dopants, and then roasted at high temperature. This method can modify lithium manganate, but due to the doping Impurities are generally lower than 3% relative to the main material, and the doping elements cannot be uniformly dispersed in the material. From a microscopic point of view, the material particles close to the dopant are doped, while the material particles far away from the dopant are not doped. Some doping sources even independently form residual particles, which seriously affect the effect of doping

[0006] Chinese patent CN102491422B discloses a production method of spherical trimanganese tetraoxide, but it is not doped, and the normal temperature cycle performance of the lithium manganate product produced by it is relatively good, but the high temperature cycle performance is relatively poor; Chinese patent CN102544472B discloses a A production method of spherical aluminum-doped trimanganese tetroxide, the method carries out the bulk phase doping of aluminum element, but in order to obtain better cycle performance and high temperature performance, it is necessary to increase the content of aluminum to more than 1% to be more obvious Therefore, the gram capacity of the material is reduced, which will significantly reduce the capacity of the battery product

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