Battery-grade cobaltosic oxide preparation method

Abstract

The invention relates to a battery-grade cobaltosic oxide preparation method, which comprises the following steps of: preparing solution of cobalt and solution of precipitator from a cobalt raw material and a precipitator by using de-ionized water respectively; preparing a precursor by using a homogeneous crystallization precipitation method, wherein the precipitate precursor is synthesized by adding the prepared solution of cobalt at a certain concentration and the solution of precipitator at a certain concentration into a reactor according to a certain molar ratio by using a cocurrent-flow feeding method, and effectively controlling chemical impurities, crystallinity of crystals, granularity, density and the like of the precursor by controlling parameters such as reaction temperature, feeding speed, PH value and stirring speed; directly filling a water-containing filter cake into a pot after washing and dewatering, and controlling grain size and crystal shape by using low-temperature dehydration phase-change calcination and high-temperature nodulizing sintering; crushing by using a machine and performing classified activation treatment; and finally, removing magnetic metal foreign bodies to obtain the battery-grade cobaltosic oxide similar to spheres. The battery-grade cobaltosic oxide has high density and high chemical purity, the grain size is easy to control, grain composition is uniform and narrow in distribution, and the magnetic metal foreign body content is low.

Description

Technical field [0001] The invention relates to a method for preparing cobalt tetroxide, in particular to a method for preparing cobalt tetraoxide used as a raw material for a positive electrode material of a lithium ion battery. Background technique [0002] Lithium-ion batteries are popular because of their high voltage, high energy density, long cycle life, and low environmental pollution. In recent years, with the further increase in the demand for small portable power sources, a good opportunity has been created for the development of the lithium-ion battery industry. The rapid development of the lithium-ion battery industry has led to the development of its cathode materials such as lithium cobalt oxide, lithium nickel cobalt oxide, lithium nickel cobalt manganese oxide and other cobalt cathode materials. Therefore, the demand for cobalt cathode materials for lithium ion batteries is also substantial. increase. Cobalt tetroxide is a raw material for lithium ion battery ca...

AI Technical Summary

Problems solved by technology

Cobalt tetroxide produced by the traditional method is amorphous, and the particle size range of the powder is wide and uneven, so that the tap density of the positive electrode material produced by it is low, resulting in a large battery volume, so it cannot meet the current development of the lithium-ion battery industry. Require

Although, by improving the existing precipitation-thermal decomposition process, researchers can obtain tricobalt tetroxide powder with regular shape. The preparation method of tricobalt tetroxide powder, the method reacts soluble cobalt salt solutions such as cobalt chloride and cobalt acetate with ammonium bicarbonate solution in a reaction kettle to obtain a cobalt carbonate precipitate, and the cobalt carbonate precipitate is washed and filtered at a certain temperature Drying, and finally calcining to obtain the final octahedral cobalt tetroxide powder, but the cobalt tetroxide produced by this method has a high impurity content, which cannot effectively control the content of magnetic metal foreign matter (such as Fe, Ni, Cr, Zn, etc.), resulting in poor consistency of the battery , poor electrochemical performance, poor safety performance and other defects

[0004] Because the particle size distribution, density, and microscopic morphology of cobalt tetroxide products have a great influence on the particle size and particle crystallinity of its precursor, it is also very important to control various operating conditions in the process of preparing its precursor cobalt salt. Patent application The Chinese invention patent application No. 200710156482.X discloses a preparation of precursor by complexation-homogeneous precipitation method, that is, the cobalt liquid is prepared into a complexed cobalt salt solution, and then the synthesis of the precursor is controlled by adding a precipitant solution Obtain a monodisperse precipitate precursor, separate the generation and growth of crystal nuclei, and obtain cobalt tetroxide with high purity, uniform particle size, and high tap density. However, this method is complicated in process and cannot effectively control the content of magnetic metal foreign matter. Cause defects such as poor battery consistency, poor electrochemical performance, and poor safety performance

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