Method for preparing low-sulfur ternary precursor

Abstract

The invention relates to a method for preparing a low-sulfur ternary precursor, relating to lithium-ion anode materials. The method for preparing the low-sulfur ternary precursor, provided by the invention, is efficient, simple and convenient, and the sulfur content of the ternary precursor can be reduced through controlling a precipitation stage and an after-treatment method and is reduced to 2,000ppm so as to meet the requirements of lithium-ion batteries for ternary materials. The method comprises the steps of: (1) simultaneously introducing three solutions, namely ternary material liquid, a sodium hydroxide solution and ammonia water, into a reaction kettle, stirring, and carrying out chemical crystallization so as to obtain a ternary precursor; (2) filtering the ternary precursor obtained in the step (1) so as to remove mother liquor, then, conveying the ternary precursor into a turbine-stirring alkaline cleaning tank, carrying out water-bath heating, stirring and then filtering; (3) washing a product obtained after alkaline cleaning by using a plate and frame filter until the conductivity of the washed water is not higher than 20 us / cm; and (4) quickly drying a washed qualified material by a rotary kiln, and sieving to obtain the low-sulfur ternary precursor, wherein the S impurity content of the obtained low-sulfur ternary precursor is not higher than 2,000ppm.

Description

technical field [0001] The invention relates to lithium ion cathode materials, in particular to a preparation method of a low-sulfur ternary precursor. Background technique [0002] With the continuous development of lithium-ion battery material technology, the application of lithium-ion batteries continues to expand, the market demand has increased sharply, and the types of lithium-ion cathode materials have diversified: lithium cobaltate, lithium manganate, ternary materials, lithium iron phosphate, vanadic acid Lithium, etc. Lithium cobalt oxide is currently the most widely commercialized cathode material. Due to its high price, it is not conducive to environmental protection, and its specific capacity is relatively low. It is gradually being replaced by a new type of green and environmentally friendly ternary cathode material. [0003] At present, the preparation methods of ternary materials are mainly divided into high-temperature solid-phase method and liquid-phase co-...

AI Technical Summary

Problems solved by technology

[0004] During the preparation of battery materials, precipitation and crystallization directly affect the physical and chemical properties of the product. The precipitation product contains a large number of impurities, such as Ca, Mg, Fe, Cu, Zn, etc. Among them, cationic impurities are easily cleaned and removed by beating and pressure washing, while anionic impurities ( Cl - , SO 4 2- , NO 3 - ) and so on cannot be removed by conventional washing methods. During the precipitation process, the anions are physically and chemically adsorbed on the surface and inside of the ternary precursor particles, forming the precipitation of basic metal sulfate double salt, which exists in the product, resulting in S content High, the preparation of ternary materials seriously affects the cycle performance. In order to effectively control the sulfate content in the product, it is necessary to control the precipitation stage and the discharge stage to reduce the SO in the ternary precursor. 4 2- content, to meet the requirements of battery materials