Preparation method of high-nickel single crystal ternary positive electrode material with core-shell structure

Abstract

The invention discloses a preparation method of a high-nickel single crystal ternary positive electrode material with a core-shell structure, which comprises the steps of 1) preparing a high-nickel single crystal lithium nickel cobalt manganate ternary positive electrode material (LiaNixCoyMnzO2, 0.9<=a<=1.2, 0.6<x<=0.9, 0<y<=0.2, 0<z<=0.3, x+y+z=1); 2) adding nano-sized low-nickel type nickel cobalt manganese hydroxide (NixCoyMnz)OH2 or cobaltosic oxide and lithium salt into absolute ethyl alcohol to obtain a solid-liquid mixture, wherein 0.3<=x<=0.6, 0.1<y<=0.3, x+y+z=1; 3) adding the high-nickel single crystal lithium nickel cobalt manganate ternary positive electrode material into the solid-liquid mixture under the stirring condition to prepare uniformly-mixed slurry; 4) drying under avacuum condition to remove absolute ethyl alcohol in the uniformly-mixed slurry; and 5) sintering and molding the dried material to prepare the material. The method is simple, and the prepared positive electrode material is stable and has excellent performance.

Description

technical field [0001] The invention belongs to the field of electrode materials for energy devices, and relates to a positive electrode material, in particular to a method for preparing a high-nickel single crystal ternary positive electrode material with a core-shell structure. Background technique [0002] At present, the main pursuit indicators of battery cathode materials in the power battery market are three aspects: high safety performance, high energy density and high cycle performance. [0003] High-nickel-based ternary cathode materials have a very high advantage in energy density compared to other cathode materials, but at the same time, due to the defects in the surface crystal structure of high-nickel ternary materials, it is very easy to undergo surface phase transition, which leads to the material system in the battery charge. Compared with other low-nickel materials, it is easier to produce oxygen during discharge, which greatly reduces the cycle performance ...

AI Technical Summary

Problems solved by technology

[0003] High-nickel-based ternary cathode materials have a very high advantage in energy density compared to other cathode materials, but at the same time, due to the defects in the surface crystal structure of high-nickel ternary materials, it is very easy to undergo surface phase transition, which leads to the material system in the battery charge. Compared with other low-nickel materials, it is easier to produce oxygen during discharge, which greatly reduces the cycle performance and safety performance of the battery

Compared with the positive electrode material with secondary particle morphology, the single crystal primary particle shape makes the positive electrode material have fewer surface defects, and the safety performance and cycle performance can be greatly improved. However, there are more or less preparation methods in the current preparation methods. The efficiency is low and it is not easy to shape. For example, the Chinese invention patent CN104409716A discloses a nickel-lithium ion battery positive electrode material with a concentration gradient and a preparation method thereof, including the following steps: (1) synthesizing the nuclear material precursor by co-precipitation method, and then Co-precipitate the shell material solution on the outside of the core material precursor, age, wash, and dry to obtain a composite precursor covered by the shell material; (2) add a lithium source to the composite precursor, grind and mix, then calcinate and cool, The positive electrode material of nickel-lithium ion battery is obtained; or the surface treatment is rough, the coating is uneven, and the surface structure is unstable in the actual application process. The method for chemical properties comprises the following steps: (1) dissolving soluble cobalt salt in the presence of water, aqueous solution or solvent to obtain soluble cobalt salt solution; (2) dispersing high-nickel ternary positive electrode material into soluble cobalt salt solution and Stir evenly to obtain a soluble cobalt salt solution containing a high-nickel ternary positive electrode material; (3) dissolve a soluble lithium salt in the presence of water, an aqueous solution or a solvent to obtain a lithium salt solution; (4) drop the lithium salt solution to a solution containing a high In the soluble cobalt salt solution of nickel ternary positive electrode material; (5) spray drying the above mixture liquid; (6) under the condition of air or oxygen, the mixture after sintering and drying at high temperature is sieved to obtain the coated positive electrode material

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