Preparation method of modified LiNi0.6Co0.2Mn0.2O2 ternary positive electrode material, and product and battery

Abstract

The invention discloses a preparation method of a modified LiNi0.6Co0.2Mn0.2O2 ternary positive electrode material, and a product and a battery. The preparation method of the ternary positive electrode material comprises the following steps of firstly introducing a magnesium element when preparing a nickel-cobalt-manganese hydroxide precursor, and then adopting an ammonium metatungstate water solution as a complexing agent at the later stage of co-precipitation reaction, wherein the ammonium metatungstate is hydrolyzed in water to show in the forms of ammonia ions and tungstate ions; the ammonia ions are used as the complexing agent to be used for compensating the co-precipitation reaction, and the tungstate ions are partially deposited on the surface of the nickel-cobalt-manganese hydroxide precursor formed in the precipitation reaction stage, so that the in-situ introduction of the tungsten element is realized; and then lithiation treatment is carried out so as to obtain the ternarypositive electrode powder containing the tungsten element on the surface. According to the method, by adding the magnesium element and the surface part in-situ doped tungsten element, the charge and discharge performance, the 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 A preparation method and product of a ternary cathode material and a battery. Background technique [0002] Lithium-ion batteries use materials capable of reversible intercalation and extraction of lithium ions as the positive and negative electrode materials of the battery, combined with an 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 increase the energy density of the battery is to use positive and negative materials with high voltage and high capacity. 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. Improving the en...

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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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