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Preparation method of ternary single crystal positive electrode material

A positive electrode material and single crystal technology, applied in the direction of positive electrodes, electrical components, battery electrodes, etc., can solve the problem of intensified side reactions between the electrolyte and the surface of electrode materials, poor cycle performance of high-nickel ternary materials, and residual ternary materials Alkali and other problems can be achieved, the surface is smooth and clean, the temperature is lowered, and the production cost is reduced.

Active Publication Date: 2020-05-19
黄冈林立新能源科技有限公司
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the ratio of lithium is too high, there will be residual alkali (LiOH or Li 2 CO 3 ) generation
The calcination temperature is 850-950°C. If the temperature is too low, it cannot fully drive the development and growth of grains. If the temperature is too high, it will lead to over-burning and aggravate the mixing of lithium and nickel in the crystal.
Such secondary spherical particles are easily broken under high-pressure conditions, so that the electrolyte penetrates into the material and fully contacts the primary particles, which intensifies the side reaction between the electrolyte and the surface of the electrode material, making the high-nickel ternary material inherently poor. The cycle performance further deteriorates

Method used

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  • Preparation method of ternary single crystal positive electrode material
  • Preparation method of ternary single crystal positive electrode material
  • Preparation method of ternary single crystal positive electrode material

Examples

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preparation example Construction

[0031] In a specific embodiment, a method for preparing a ternary single crystal positive electrode material of the present invention may include the following steps:

[0032] S1: Weigh the nickel salt and cobalt salt, and dissolve them in the mixed solution of ethanol and water with the ratio of the amount of substances as x:1-x, and make a solution with the concentration of the total substances being 0.1-1mol / L. Then the solution is added to a polytetrafluoroethylene-lined high-pressure reactor, oxalic acid and urea are added to the mixed solution, stirred for 10min-20min, and then the reactor is sealed. The molar concentration of oxalic acid is 0.1~2mol / L, and the molar concentration of urea is 0.1mol / L~4mol / L. From room temperature to 140-220°C, keep warm for 6h-12h.

[0033] S2: Cool to room temperature, wash the precipitate with deionized water until the pH value of the filtrate drops to 6.0-7.0. The filter cake is then dried in a vacuum oven at 60-120°C for 6-12 hours...

Embodiment 1

[0037] This embodiment provides an 811 ternary single crystal positive electrode material, which is prepared by the following steps:

[0038] Get 50ml ethanol and 50ml deionized water to form a mixed solution, add 2.2147gNi(CH 3 COO) 2 4H 2 O and 0.2740g Co(CH 3 COO) 2 4H 2 O, stirred until completely dissolved, after which the solution was transferred to a polytetrafluoroethylene-lined autoclave. Add 1.2607g H to the reactor 2 C 2 o 4 2H 2 O and 1.2012g CO(NH 2 ) 2 , and stir until completely dissolved. Seal the autoclave, raise the temperature from room temperature to 180°C at a rate of 2°C / min, and keep the temperature for 12h. Heating was stopped, cooled to room temperature, and the precipitate was washed until the pH of the filtrate was 6.0. Dry the precipitate in a vacuum oven at 80°C for 12 hours to obtain the precursor Ni 0.89 co 0.11 C 2 o 4 2H 2 O. The precursor is nickel-cobalt oxalate with a micron scale and a rod-like shape. See the attached SEM...

Embodiment 2

[0042] This example provides a method for preparing a 622 ternary single-crystal positive electrode material, in which the excess of lithium hydroxide is 50%, which is prepared by the following steps:

[0043] When preparing the nickel-cobalt oxalate precursor, adjust the quality of nickel acetate and cobalt acetate in embodiment 1 to 1.8663g and 0.6227g respectively, be dissolved in the mixed solution of ethanol and deionized water, the amount concentration that is mixed with total substance is 0.1mol / L mixed solution, the precursor prepared is Ni 0.75 co 0.25 C 2 o 4 2H 2 O. When the precursor is lithiated, adjust the precursor and Mn(NO 3 ) 2 The masses of the solutions were up to 0.4387g and 0.2147g, respectively. At this time, the ratio of the amount of lithium (Li) in the lithium hydroxide to the total amount of transition metals (Ni+Co+Mn) is 1.5:1. Other steps are the same as in Example 1, that is, the 622-type ternary cathode material is obtained.

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Abstract

The invention provides a preparation method of a ternary single crystal positive electrode material, which belongs to the technical field of lithium ion batteries. The preparation method comprises thefollowing steps of: dissolving a nickel salt and a cobalt salt in a mixed solution of ethanol and water to obtain a mixed salt solution, adding oxalic acid and urea into the mixed salt solution, stirring, and heating to a reaction temperature in a high-pressure reaction kettle to obtain a nickel-cobalt oxalate precursor, uniformly mixing the precursor, a manganese source and a lithium source exceeding a stoichiometric ratio, heating to a presintering temperature in an oxygen atmosphere, keeping the temperature, heating to a sintering temperature, and keeping the temperature, and cooling to room temperature to obtain the ternary single crystal positive electrode material. According to the preparation method, a binary precursor is adopted, the pH value and the stirring speed of the system do not need to be accurately regulated, and nitrogen protection is not needed; the introduction of a lithium source with a super stoichiometric ratio reduces the sintering temperature in the lithiationprocess. The two points can greatly reduce the production cost of the ternary positive electrode material. The lithium ion battery prepared from the ternary positive electrode material synthesized bythe method is high in charge-discharge coulombic efficiency and good in cycle performance.

Description

technical field [0001] The invention relates to a preparation method of a positive electrode material, in particular to a preparation method of a ternary single crystal positive electrode material, and belongs to the technical field of lithium ion batteries. Background technique [0002] With the continuous development of the new energy industry, people have put forward higher and higher requirements for the energy density and safety of lithium-ion power batteries. In order to increase energy density and reduce costs, most of the power battery industry tends to use high-nickel and low-cobalt ternary cathode materials, namely LiNi 1-x-y co x mn y o 2 (x+y£0.2). In ternary materials, the increase of nickel content can significantly increase the specific capacity and energy density of the material, but the phase structure of the material will become unstable at the same time. The obvious performance is that the first charge and discharge coulombic efficiency of the materia...

Claims

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Application Information

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IPC IPC(8): H01M4/505H01M4/525H01M10/0525
CPCH01M4/505H01M4/525H01M10/0525H01M2004/028Y02E60/10
Inventor 张友祥马晓玲
Owner 黄冈林立新能源科技有限公司