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High-nickel positive electrode material with high cycle stability and preparation method thereof

A technology of cycle stability and positive electrode material, applied in positive electrodes, active material electrodes, chemical instruments and methods, etc., can solve problems such as electrolyte corrosion, battery failure, battery performance degradation, etc., achieve good surface stability, and improve production. Efficiency, improve stability effect

Active Publication Date: 2022-05-31
泾河新城陕煤技术研究院新能源材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the positive electrode material with secondary particle agglomeration balls is unavoidable to be corroded by the electrolyte because the surface of the particles directly contacts the electrolyte during the cycle.
like figure 1 As shown, as the number of cycles increases, the crystal volume of the material shrinks and expands reciprocally, the gap before the primary particles on the surface gradually increases, and the electrolyte invades the primary particles from the primary particle boundary on the surface along the gap between the primary particles and gradually corrodes. The surface of each primary particle causes the surface of the material to be corroded from the surface to the interior of the primary particle, eventually resulting in particle pulverization, a sharp decline in battery performance, and battery failure
[0003] Generally, high-nickel materials are sensitive to moisture and are easy to react with moisture in the air. The surface is prone to generate high content of alkaline substances lithium hydroxide and lithium carbonate, which reduces the stability of the surface / interface of the material.
The water washing process is usually used to reduce the alkali content on the surface of high-nickel cathode materials, but the process requirements are strict, and the surface structure of the material is easily damaged after washing, which directly affects the cycle life of the material

Method used

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  • High-nickel positive electrode material with high cycle stability and preparation method thereof
  • High-nickel positive electrode material with high cycle stability and preparation method thereof

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preparation example Construction

[0032] The preparation method of the high-nickel cathode material with high cycle stability of the present invention comprises the following steps:

[0033] Step 1, raw material preparation, uniformly mixing the high-nickel positive electrode material precursor, additives, flux and lithium source to prepare mixture A;

[0034] In step 1, the precursor is a homogeneous co-precipitated hydroxide containing Ni, Co and Me elements.

[0035] The amount of the additive in step 1 is 0.1% to 2% of the mass of the precursor;

[0036] Flux is one or more of boric acid, sodium chloride, potassium chloride in step 1;

[0037] The content of the flux in step 1 is 0.01% to 3% of the mass of the precursor;

[0038] The molar weight of lithium in the lithium source in step 1 is 0.7-0.8 times the sum of the molar weights of Ni, Co and Me.

[0039] Step 2, putting the mixture A into a sagger, placing it in a high-temperature device, performing primary sintering under an oxygen atmosphere, an...

Embodiment 1

[0057] Step 1, the hydroxide Ni 0.8 co 0.1 mn 0.1 (OH) 2 , lithium hydroxide, weigh the material according to the ratio of n Li:n(Ni+Co+Mn)=0.7, add the additive titanium oxide, the quality is 2% of the precursor mass, add the fluxing agent sodium chloride, the mass is the precursor 0.01% of the mass, mix the above substances evenly to prepare mixture A;

[0058] Step 2, put the mixture A into a sagger, place it in a high-temperature equipment, and keep it at 300°C for 8 hours under an oxygen atmosphere, then raise the temperature to 450°C and keep it for 16 hours, and sieve the obtained primary sintered material to obtain the secondary particle surface Primary sintered material with evenly distributed pore diameter;

[0059] Step 3, weigh the primary sintered material and lithium hydroxide according to the ratio of n Li:n(Ni+Co+Mn)=0.35 according to the primary sintered material; weigh the modifier zirconia with a particle size of 30nm, and the mass is the primary sintere...

Embodiment 1 and comparative example 1

[0066] Embodiment 1 and comparative example 1 performance detection:

[0067] Using the two materials of Example 1 and Example 1 of the present invention, respectively take 5g of powder samples and place them in 95g of deionized aqueous solution, stir for 5min and then suction filter. Use the Mettlertoledo T50 potentiometric titrator to measure Li in the solution according to the equivalence point 2 CO 3 and the content of LiOH, and take the content as the residual alkali content on the surface of the material. It can be seen from Table 1 that: Example 1 of the present invention adopts lower temperature sintering to easily obtain the characteristic primary sintered material of the target invention, and the surface residual alkali value of the final target material is low.

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Abstract

The invention discloses a preparation method of a high-nickel positive electrode material with high cycle stability. The preparation method specifically comprises the following steps: step 1, preparing a mixture A; step 2, putting the mixture A into a sagger, and putting the sagger into high-temperature equipment to obtain a primary sintering material; step 3, uniformly mixing the primary sintering material obtained in the step 2 with a lithium source, a modifier and an organic solvent to prepare a mixture B; step 4, putting the mixture B into a sagger, and putting the sagger into high-temperature equipment to prepare a secondary sintering product; and step 5, uniformly mixing the secondary sintering product with a coating agent, putting the mixture into a sagger, putting the sagger into high-temperature equipment, performing third sintering in an oxygen atmosphere, and crushing and screening the third sintering product to obtain the target high-nickel positive electrode material. By adopting the method, the corrosion resistance of the material surface and the grain boundary between the primary particles in the particles is improved, so that the stability of the material is improved, the pulverization phenomenon of the material is delayed, and the service life of the battery is prolonged.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and relates to a high-nickel positive electrode material with high cycle stability, and also relates to a preparation method of the positive electrode material. Background technique [0002] Due to the advantages of high charge-discharge voltage, high charge-discharge specific capacity and high energy density, high-nickel cathode materials have shown great development potential in the lithium-ion battery market, and have quickly become a hot spot in the research and development and application of lithium-ion battery cathode materials. . However, the positive electrode material with secondary particle agglomeration balls is unavoidable to be corroded by the electrolyte because the surface of the particles directly contacts the electrolyte during the cycle. Such as figure 1 As shown, as the number of cycles increases, the crystal volume of the material shrinks and expands reciprocal...

Claims

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Application Information

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IPC IPC(8): C01G53/00H01M4/36H01M4/485H01M4/505H01M4/525H01M10/0525
CPCC01G53/42C01G53/44H01M4/362H01M4/525H01M4/505H01M4/485H01M10/0525C01P2006/40H01M2004/028Y02E60/10
Inventor 张超张诚李宇王继锋徐可孙豪李领寇亮屈涛
Owner 泾河新城陕煤技术研究院新能源材料有限公司