Modified lini 0.6 co 0.2 mn 0.2 o 2 Preparation method and product of ternary cathode material and battery

Abstract

The invention discloses a modified LiNi 0.6 co 0.2 mn 0.2 o 2 A preparation method and product of a ternary cathode material and a battery. The preparation method of the ternary positive electrode material includes: first introducing magnesium element when preparing the precursor of nickel cobalt manganese hydroxide, and then using ammonium metatungstate aqueous solution as complexing agent in the later stage of co-precipitation reaction, using ammonium metatungstate in the After hydrolysis in water, ammonia ions and tungstate ions appear, and ammonia ions are used as complexing agents to compensate for the co-precipitation reaction, while tungstate ions are partially deposited on the surface of the nickel-cobalt-manganese hydroxide precursor formed in the precipitation reaction stage, The in-situ introduction of tungsten element is realized, followed by lithiation treatment to obtain ternary cathode powder with tungsten element on the surface. In the present invention, by adding magnesium element and in-situ doping tungsten element on the surface, the charging and discharging performance, cycle performance and the like of the obtained modified ternary positive electrode powder are effectively improved.

Description

technical field [0001] The invention relates to a nickel-cobalt-manganese ternary positive electrode material with high nickel content, in particular to modified LiNi 0.6 Co 0.2 Mn 0.2 O 2 Preparation method, product and battery of ternary cathode material. Background technique [0002] Lithium ion batteries use materials capable of reversible intercalation and deintercalation of lithium ions as the positive electrode material and negative electrode material of the battery, combined with appropriate electrolyte or solid electrolyte powder film to form a lithium ion secondary battery system. Because the energy of a battery depends on the product of its voltage and capacity, the means to improve the energy density of the battery is to use high-voltage and high-capacity positive and negative electrode materials. For the same negative electrode material, the higher the capacity and potential of the positive electrode material, the higher the energy density of the battery. I...

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Problems solved by technology

[0008] Although there are a variety of ternary positive electrode powder surface coating or doping treatment methods as mentioned above, they are all coating layers superimposed on the surface of the ternary positive electrode powder, and there is no method based on doping tungsten elements to replace the surface part of the ternary positive electrode powder. The nickel, cobalt, and manganese atoms in the crystal structure, that is to say, did not use the high valence of tungsten to reduce the valence change of nickel, cobalt, and manganese in the layered crystal structure during charge and discharge, and did not take into account the The doping of high valence tungsten elements in the layered crystal structure leads to an increase in the concentration of vacancies, which is conducive to the diffusion of lithium ions to achieve the purpose of improving the performance of the ternary cathode powder through doping

On the other hand, those skilled in the art know that the surface of high nickel content ternary positive electrode powder is alkaline, if it is directly applied to the subsequent pulping process, it will The problem of causing the slurry to become a gel (jelly-like colloid); if you want to remove the surface alkalinity of the ternary positive electrode powder, although you can use water washing, this will cause the loss of lithium ions on the surface and cause the discharge of the ternary positive electrode material Capacity reduction

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