Method for preparing multi-element precursor with low impurity content

Abstract

The invention belongs to the technical field of lithium ion battery positive electrode materials and in particular discloses a method for preparing a multi-element precursor with low impurity content. According to the method disclosed by the invention, impurities contained in the multi-element precursor are separated, and the method comprises the following steps: simultaneously adding a ternary mixed metal salt solution of inorganic salts or organic salts of nickel salts, cobalt salts and manganese / aluminum salts, a precipitator and a complexing agent into a reactor, stirring, and performing coprecipitation so as to obtain precursor suspension B; guiding the suspension and a mother solution into an electromagnetic separation tank, stirring, establishing magnetic fields in different directions, respectively constraining residual positive ions and negative ions, dissociating so as to obtain precursor suspension D in which impurity ions are removed; and filtering, drying, screening, removing the magnetic powder, thereby obtaining the multi-element precursor product. The process disclosed by the invention is simple, high-efficiency, low in cost, low in pollution, energy-saving and environmentally friendly, and the prepared multi-element precursor product is low in impurity content, meets the positive electrode material requirements of lithium ion batteries and is suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the technical field of cathode materials for lithium ion batteries, and in particular relates to a preparation method of a low-impurity multi-element precursor. Background technique [0002] Lithium-ion batteries have been widely used in portable electronic devices, large-scale energy storage power stations and electric vehicles because of their advantages such as high working voltage, long cycle life, no memory effect, small self-discharge effect, and environmental friendliness. At present, lithium cobalt oxide, the traditional commercial lithium-ion battery cathode material, is not mature enough to meet the needs of lithium-ion batteries with higher specific energy and high power density in the future because of the high price of cobalt as a strategic resource and the need to match high-voltage electrolytes. requirements for battery development. Now, multi-component materials have become an important development direction be...

AI Technical Summary

Problems solved by technology

[0009] In the existing preparation technology of multi-component precursors, in order to realize the separation of multi-component precursors and impurity ions, a large amount of lye or pure water is used to repeatedly wash and filter the precursors, and the impurities are adsorbed on the surface of the precursors by the washing liquid. The anions and cations of the anions and cations are dissolved many times, but the adsorption performance of the hydroxide precursor is strong, and the washing process cannot completely remove the entrapped Na + and SO 4 2- Even if the auxiliary washing methods such as improved ultrasonic washing and centrifugal washing are used to effectively remove impurity ions, the content of impurity ions in the multi-component precursor can only be reduced by a certain percentage each time, and repeated washing is required, which is time-consuming and laborious. After multiple washings, the multi-element precursor and impurities cannot be effectively separated; moreover, the existing process uses a large amount of water and requires high purity of water, which is usually deionized water or pure water, which will produce a large amount of Waste liquid must be equipped with a complete waste liquid treatment system, which increases production costs, and incomplete waste liquid treatment will also cause adverse effects and damage to the environment, which is contrary to the concept of energy conservation and environmental protection under the current social and economic situation

[0010] Therefore, there is no effective solution in the prior art

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