Cathode material, preparation method of cathode material, and lithium ion battery

A positive electrode material and slurry technology, which is applied in the field of positive electrode materials and its preparation, can solve the problems of battery volume energy density decrease, gaps cannot be filled, unfavorable processing, etc., to improve the first charge and discharge performance, dense and regular arrangement, The effect of reducing space waste

Active Publication Date: 2020-02-07
SHENZHEN BYD LITHIUM BATTERY
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  • Application Information

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Problems solved by technology

Therefore, the morphology and particle size are relatively less controllable when performing high-pressure synthesis reactions at a single concentration
[0006] Patent CN201110320504.8 discloses a method for preparing lithium iron phosphate in phosphate-based materials. The method prepares a two-dimensional plane with an average particle size of 0.2- 1μm, with an average thickness of 50-90nm, but its secondary average particle size agglomerates and grows into large particles of 12-28μm. Although this material may have good electrochemical performance, but because the average particle size is too large, When coating the positive electrode, the thickness of the electrode piece is generally controlled at 60-100 μm, and the roller pressure is easy to break the large particles, and there will be defects such as material drop, which is not conducive to processing
In addition, when the overall particle size exceeds a certain level, large gaps are easily formed between large particles and cannot be filled, resulting in waste of volume and a decrease in the volumetric energy density of the battery.

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  • Cathode material, preparation method of cathode material, and lithium ion battery
  • Cathode material, preparation method of cathode material, and lithium ion battery
  • Cathode material, preparation method of cathode material, and lithium ion battery

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preparation example Construction

[0031] Second object of the present invention provides a kind of preparation method of cathode material, described method comprises the following steps:

[0032] S1. After mixing the M source solution, the phosphorus source solution, the lithium source solution and the pH regulator, control the pH value of the reaction system to 8-10, perform emulsification and shearing to obtain slurry A, wherein the M source is a ferrous iron source Or ferrous iron source and manganese source;

[0033] S2. Suction filter the slurry A under the first inert atmosphere to obtain the slurry B, put the slurry B into the high-pressure reactor, and react to obtain the slurry C, the reaction temperature is 120-240°C, and the reaction time is 2-8h ;

[0034] S3. Continue to react in the autoclave after diluting the slurry C, the reaction temperature is 120-240°C, and the reaction time is 2-8h;

[0035] S4, filtering, washing and drying the product obtained in step S3 to obtain a positive electrode ...

Embodiment 1

[0063] Get 4mol ferrous chloride (purity is 99.9%), 4.04mol ammonium phosphate (purity is 99.5%) and 4000g deionized water, be made into the mixed solution of iron source and phosphorus source that iron concentration is 1mol / L, get 12.8mol Lithium chloride (purity is 99.5%), 3500g deionized water is made into the lithium source solution that lithium concentration is 3.66mol / L, gets 0.5mol sodium hydroxide (purity is 99.5%), 400g deionized water is made into concentration and is 1.25 mol / L pH regulator. Put the mixed solution of iron source and phosphorus source into the emulsified shear tank, turn on the shearer and stirring paddle, and keep the speed of the stirring paddle at 200r / min; add the lithium source solution and pH regulator at a uniform speed within 80min to shear In the reaction tank, after the lithium source solution is completely added to the reaction tank, the pH of the entire reaction system is finally controlled to 9.0 with the configured pH regulator to ensur...

Embodiment 2

[0065] Get 3.0mol ferrous sulfate (purity is 100%), 3.05mol ammonium hydrogen phosphate (purity is 99.2%) and 2500g deionized water, be made into the mixed solution of iron source and phosphorus source that iron concentration is 1.2mol / L, Get 9.05mol lithium nitrate (purity is 99.5%), 2511g deionized water are made into the lithium source solution that lithium concentration is 3.0mol / L, get 3.55mol potassium hydroxide, 2180g deionized water are made into concentration and be 1.63mol / L pH regulator. Put the mixed solution of iron source and phosphorus source into the emulsified shear tank, turn on the shearer and stirring paddle, and keep the speed of the stirring paddle at 400r / min; at the same time, add the lithium source solution and pH regulator at a uniform speed of about 40ml / min In the shearing reaction tank, after the lithium source solution is completely added in the reaction tank, the pH control of the entire reaction system is finally controlled to 8.5 with a configure...

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Abstract

The invention discloses a cathode material, a preparation method of the cathode material, and a lithium ion battery. The cathode material includes LiMPO4 secondary sphere particles, the LiMPO4 secondary sphere particles are formed by stacking nanosheet-shaped LiMPO4 secondary particles, and at least part of nanosheet-shaped LiMPO4 secondary particles have a multilayer sheet-shaped structure, wherein M is selected from Fe, or M is selected from Mn or Fe. The cathode material can significantly improve the first charge and discharge performance, cycle performance, rate performance and low-temperature performance of the lithium ion battery when applied to the lithium ion battery.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a positive electrode material, a preparation method thereof and a lithium ion battery. Background technique [0002] Lithium-ion batteries have the advantages of high voltage, high energy density, good cycle performance, and no memory effect, and are widely used. Among them, the price of positive electrode materials occupies a considerable proportion in the cost of the entire Li-ion battery. At present, the cathode materials of the phosphate series, such as lithium iron phosphate, lithium manganese phosphate, and lithium iron manganese phosphate, have good safety performance, high cycle stability and high theoretical capacity, and are recognized as safe, cost-effective and long-term. Long-life, environmentally friendly cathode materials are widely used in the field of new energy vehicles. However, with the continuous expansion of the new energy market, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/45H01M4/58H01M10/0525B82Y40/00
CPCC01B25/45H01M4/5825H01M10/0525B82Y40/00C01P2004/03C01P2004/20C01P2006/40C01P2004/01Y02E60/10
Inventor 段敏李阳曹文玉张运朋
Owner SHENZHEN BYD LITHIUM BATTERY
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