CN112397700A - Boron-yttrium composite coated high-nickel cathode material and preparation method thereof - Google Patents

Boron-yttrium composite coated high-nickel cathode material and preparation method thereof Download PDF

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CN112397700A
CN112397700A CN202011304057.2A CN202011304057A CN112397700A CN 112397700 A CN112397700 A CN 112397700A CN 202011304057 A CN202011304057 A CN 202011304057A CN 112397700 A CN112397700 A CN 112397700A
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boron
cathode material
yttrium
matrix
lini
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徐可
寇亮
张�诚
张超
刘增
田占元
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Shaanxi Coal and Chemical Technology Institute Co Ltd
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Abstract

The invention discloses a boron-yttrium composite coated high-nickel anode material and a preparation method thereofxCoyM1‑x‑yO2Wherein x is more than or equal to 0.80 and less than or equal to 0.96, y is more than or equal to 0.00 and less than or equal to 0.11, x + y is less than or equal to 1, M is Al,One of Mn, W and Mg; the boron-yttrium composite coating layer comprises yttrium oxide and a lithium layer containing boric acid, the boric acid and the yttrium oxide are used as coating agents, and by means of synergistic effect generated by excellent flowability of the boric acid and excellent chemical stability of the yttrium oxide, the coating layer material is uniformly distributed on the surface of the matrix anode material, so that the interfacial reaction between electrolyte and the anode material can be effectively reduced, the cycle performance of the anode material is remarkably improved, the cycle life of a battery is prolonged, the coating product has good conductivity, and the discharge capacity of the battery can be improved.

Description

Boron-yttrium composite coated high-nickel cathode material and preparation method thereof
Technical Field
The invention belongs to the technical field of ternary cathode materials of lithium ion batteries, and particularly relates to a boron-yttrium composite coated high-nickel cathode material and a preparation method thereof.
Background
In recent years, with the vigorous popularization and application development of new energy automobiles, lithium ion batteries are widely applied to power systems of electric automobiles and hybrid automobiles due to the advantages of low cost, high energy density, environmental friendliness and the like. The performance of lithium ion batteries mainly depends on the positive electrode material, and among many positive electrode materials, the layered high nickel positive electrode material has received extensive attention and research due to its high energy density and good thermal stability. This material has greatly limited its commercialization and practical application due to several drawbacks. For example, high nickel content can exacerbate the Li/Ni mixed arrangement, cause structural changes during cycling, and lead to cracks and halite phases, which in turn deteriorate cycling performance. Furthermore, as the Ni content increases, the total alkali LiOH/Li in the raw material2CO3The viscosity of the slurry is increased in the pulping process, and the processing performance of the material is deteriorated.
Researchers have developed many ways to solve the above problems. The water washing is to reduce the total alkali LiOH/Li2CO3But has a slight effect on the surface structure of the material, with a concomitant reduction in capacity; the surface coating modification is an effective supplement method, and the coating material can effectively prevent the matrix anode material and the matrix cathode material from being mixedThe direct contact of the electrolyte reduces the dissolution of metal cations, thereby improving the processing performance and the cycle safety performance of the material and ensuring the electrochemical stability of the system. Yttria is a common ceramic additive material and can be used as a coating agent of a positive electrode material, but the improvement of cycle performance is limited by coating single yttria, and the uniformity of coating is difficult to guarantee. The boric acid is helpful for improving the uniformity of the coating layer, thereby improving the comprehensive performance of the battery. Therefore, boric acid and yttrium oxide are adopted for composite coating, so that a synergistic effect is expected to be generated, and the cycle performance of the material is remarkably improved.
Disclosure of Invention
In order to solve the problems in the prior art, the invention aims to provide a boron-yttrium composite coated high-nickel cathode material and a preparation method thereof, so as to solve the problem of LiNixCoyM1-x-yO2The invention can obviously reduce the total alkali LiOH/Li of the anode material2CO3And the composite coating layer can effectively prevent the reaction of the anode material and the electrolyte, and improve the cycle performance and the safety performance of the material.
In order to achieve the above object, the present invention provides a boron-yttrium composite coated high nickel positive electrode material, which comprises a matrix positive electrode material and a boron-yttrium composite coating layer coated on the matrix positive electrode material, wherein the molecular formula of the matrix positive electrode material is LiNixCoyM1-x-yO2Wherein x is more than or equal to 0.80 and less than or equal to 0.96, y is more than or equal to 0.00 and less than or equal to 0.11, x + y is less than or equal to 1, and M is one of Al, Mn, W and Mg; the boron yttrium composite cladding layer comprises yttrium oxide and a lithiated layer containing boric acid.
Further, the boric acid accounts for 0.34-0.68 wt% of the matrix cathode material; the weight percentage of yttrium oxide in the matrix anode material is 0.05 wt% -0.20 wt%; the boric acid is 2000 meshes, and the yttrium oxide is in a nanometer level.
Furthermore, in the boron-yttrium composite coating layer, the weight percentage of boron element in the matrix anode material is 0.06 wt% -0.12 wt%; the weight percentage of yttrium element in the matrix anode material is 0.04 wt% -0.16 wt%.
The invention also provides a preparation method of the boron-yttrium composite coated high-nickel cathode material, which comprises the following steps:
s1, mixing a certain amount of high-nickel positive electrode material precursor with a lithium source, and sintering for the first time to obtain LiNixCoyM1-x-yO2Primary sintering to obtain a finished product;
s2, obtaining LiNixCoyM1-x-yO2Washing, separating and drying the primary sintered product to obtain a matrix cathode material;
and S3, mixing the matrix positive electrode material obtained in the step S2 with a coating agent boric acid-yttrium oxide, and performing secondary sintering to obtain the boron-yttrium composite coating positive electrode material.
Further, in step S1, the molecular formula of the high-nickel positive electrode material precursor is NixCoyM1-x-y(OH)2The lithium source is lithium hydroxide monohydrate, and the molecular formula of the lithium hydroxide monohydrate is LiOH & H2O; the molar ratio of the precursor to the lithium hydroxide monohydrate is 1 (1-1.05).
Further, in the step S1, the primary sintering is performed in an oxygen atmosphere, the temperature is 680 ℃ to 780 ℃, the heat preservation time is 8h to 16h, and the oxygen content in the oxygen atmosphere is more than 90%.
Further, in the step S2, the LiNixCoyM1-x-yO2Washing the primary sintered product with deionized water, wherein the deionized water and LiNi are used for washingxCoyM1-x-yO2The mass ratio of the primary sintered finished product is (1-3) to 1; the water washing is stirring water washing, the stirring water washing time is 15min-60min, and the stirring linear speed is 900 rpm.
Further, in the step S2, the separation is suction filtration separation, the drying temperature is 100-150 ℃, and the time is 4-10 h.
Further, in the step S3, the matrix positive electrode material and the coating agent boric acid-yttrium oxide are mixed by a ball milling process, wherein a mass ratio of the ball material is 1.5:1, and a rotation speed is 1000 rpm.
Further, the secondary sintering is carried out in an oxygen atmosphere, the oxygen content is more than 90%, the pressure is 20Pa-40Pa, the temperature of the secondary sintering is 250-350 ℃, and the heat preservation time is 2h-10 h.
Compared with the prior art, the application has at least the following beneficial effects:
according to the invention, boric acid and yttrium oxide are used as coating agents, and by virtue of a synergistic effect generated by excellent fluidity of boric acid and excellent chemical stability of yttrium oxide, the coating material is uniformly distributed on the surface of the matrix anode material, so that the interface reaction between the electrolyte and the anode material can be effectively reduced, the cycle performance of the anode material is obviously improved, the cycle life of the battery is prolonged, and the coated product has good conductivity and can improve the discharge capacity of the battery.
In the invention, the total alkali LiOH/Li of the anode material after washing is combined with a composite coating process2CO3The content is obviously reduced, the slurry viscosity in the pulping process is favorably reduced, the slurry is more uniformly coated, the processing performance of the anode material is improved, the uniformity of the battery capacity is improved, and the comprehensive performance of the battery is improved.
Drawings
FIG. 1 shows LiNi compositely coated with boron and yttrium obtained in example 3 of the present invention0.91Co0.06Al0.03O2Schematic diagram of the cathode material under a 30 k-fold electron microscope.
FIG. 2 shows LiNi compositely coated with boron and yttrium prepared in example 3 of the present invention0.91Co0.06Al0.03O2The button cell prepared from the positive electrode material has a first charge-discharge curve at a rate of 0.1C.
FIG. 3 is LiNi compositely coated with boron and yttrium prepared in example 3 of the present invention0.91Co0.06Al0.03O2And (3) a circulation curve of the button cell prepared from the positive electrode material at the rate of 1C.
FIG. 4 shows LiNi compositely coated with boron and yttrium prepared in example 3 of the present invention0.91Co0.06Al0.03O2And (3) a cycle curve of the soft package battery prepared from the positive electrode material at a rate of 1C.
Detailed Description
The following further description of the present invention, with reference to the drawings and the detailed description, is only for the purpose of further illustrating the present invention and should not be construed as limiting the scope of the present invention.
Example 1
Step 1: weighing LiNi with a certain massxCoyM1-x-yO2Precursor of molecular formula Ni0.83Co0.11Mn0.06(OH)2Mixed with lithium hydroxide (LiOH. H)2O) and then sintering at the oxygen atmosphere to obtain LiNi0.83Co0.11Mn0.06O2And sintering the finished product at one time. Wherein the molar ratio of the precursor to the lithium hydroxide is 1:1, the sintering temperature is 780 ℃, the heat preservation time is 10h, and the oxygen content is more than 90%.
Step 2: weighing LiNi with a certain mass0.83Co0.11Mn0.06O2Adding the primary sintered finished product into deionized water according to the mass ratio of water to material of 3:1, stirring and washing for 15min, wherein the stirring linear velocity is 900 rmp; after washing, carrying out suction filtration and separation, and drying for 10h at 100 ℃ to obtain LiNi0.83Co0.11Mn0.06O2And (3) a matrix cathode material.
And step 3: carrying out ball milling and mixing on the matrix anode material and the coating agent boric acid-yttrium oxide, wherein the boric acid accounts for 0.68 wt% of the matrix anode material, the yttrium oxide accounts for 0.20 wt% of the matrix anode material, the mass ratio of ball materials is 1.5:1 during ball milling, and the rotating speed is 1000 rpm. Then carrying out secondary sintering in an oxygen atmosphere to obtain the LiNi coated with the boron-yttrium composite0.83Co0.11Mn0.06O2The secondary sintering temperature is 350 ℃, the heat preservation time is 10 hours, the oxygen content is more than 90 percent, and the pressure is (23 +/-3 Pa).
Composite coated LiNi prepared in this example0.83Co0.11Mn0.06O2The discharge specific capacity of the button cell of the anode material finished product at 0.1C multiplying power is 203.3mAh/g, and the capacity is ensured after 100 cycles at 1C multiplying powerThe retention rate was 91.6%. The total alkali content of the positive electrode material is 0.460%.
Example 2
Step 1: weighing LiNi with a certain massxCoyM1-x-yO2Precursor of molecular formula Ni0.88Co0.09Mn0.03(OH)2Mixed with lithium hydroxide (LiOH. H)2O) and then sintering at the oxygen atmosphere to obtain LiNi0.88Co0.09Mn0.03O2And sintering the finished product at one time. Wherein the molar ratio of the precursor to the lithium hydroxide is 1:1.05, the sintering temperature is 730 ℃, the heat preservation time is 12h, and the oxygen content is more than 90%.
Step 2: weighing LiNi with a certain mass0.88Co0.09Mn0.03O2And (3) adding the once-sintered finished product into deionized water according to the mass ratio of water to material of 2:1, stirring and washing for 30min at the stirring linear speed of 900rmp, carrying out suction filtration separation after washing, and drying at 120 ℃ for 6h to obtain the LiNi0.88Co0.09Mn0.03O2And (3) a matrix cathode material.
And step 3: mixing a matrix anode material and a coating agent boric acid-yttrium oxide through ball milling, wherein the boric acid accounts for 0.51 wt% of the matrix anode material, the yttrium oxide accounts for 0.10 wt% of the matrix anode material, the mass ratio of ball materials is 1.5:1 during ball milling, and the rotating speed is 1000 rpm. Then, the LiNi coated with the boron-yttrium composite is obtained by secondary calcination in the oxygen atmosphere0.88Co0.09Mn0.03O2The secondary sintering temperature is 290 ℃, the heat preservation time is 8 hours, the oxygen content is more than 90 percent, and the pressure is 30 +/-3 Pa.
Composite coated LiNi prepared in this example0.88Co0.09Mn0.03O2The discharge specific capacity of the cathode material finished button cell under 0.1C multiplying power is 212.3mAh/g, and the capacity retention rate is 92.8% after 100 cycles under 1C multiplying power. The total alkali content of the positive electrode material was 0.477%.
Example 3
Step 1: weighing LiNi with a certain massxCoyM1-x-yO2Precursor of molecular formula Ni0.91Co0.06Al0.03(OH)2Mixed with lithium hydroxide (LiOH. H)2O) and then sintering at the oxygen atmosphere to obtain LiNi0.91Co0.06Al0.03O2And sintering the finished product at one time. Wherein the molar ratio of the precursor to the lithium hydroxide is 1:1.02, the sintering temperature is 710 ℃, the heat preservation time is 12h, and the oxygen content is more than 90%.
Step 2: weighing LiNi with a certain mass0.91Co0.06Al0.03O2Adding the primary sintered finished product into deionized water according to the mass ratio of water to material of 1.5:1, stirring and washing for 30min, wherein the stirring linear speed is 900 rmp; washing with water, performing suction filtration and separation, and drying at 120 ℃ for 8h to obtain LiNi0.91Co0.06Al0.03O2And (3) a matrix cathode material.
And step 3: carrying out ball milling and mixing on the matrix anode material and the coating agent boric acid-yttrium oxide, wherein the boric acid accounts for 0.34 wt% of the matrix anode material, the yttrium oxide accounts for 0.05 wt% of the matrix anode material, the mass ratio of ball materials is 1.5:1 during ball milling, and the rotating speed is 1000 rpm. Then carrying out secondary sintering in an oxygen atmosphere to obtain the LiNi coated with the boron-yttrium composite0.91Co0.06Al0.03O2The secondary sintering temperature is 265 ℃, the heat preservation time is 6 hours, the oxygen content is more than 90 percent, and the pressure is 25 +/-3 Pa.
Composite coated LiNi prepared in this example0.91Co0.06Al0.03O2The discharge specific capacity of the finished button cell of the cathode material at the multiplying power of 0.1C is 217.4mAh/g, the capacity retention rate of 100 cycles at the multiplying power of 1C is 93.7%, the capacity retention rate of 800 cycles of the soft package cell at the multiplying power of 1C is 81.7%, and the total alkali content of the cathode material is 0.490%.
Example 4
Step 1: weighing LiNi with a certain massxCoyM1-x-yO2Precursor of molecular formula Ni0.91Co0.07W0.02(OH)2Mixed with lithium hydroxide (LiOH. H)2O) and then sintering at the oxygen atmosphere to obtain LiNi0.91Co0.07W0.02O2And sintering the finished product at one time. Wherein the molar ratio of the precursor to the lithium hydroxide is 1:1.01, the sintering temperature is 680 ℃, the heat preservation time is 16h, and the oxygen content is more than 90%.
Step 2: weighing LiNi with a certain mass0.91Co0.07W0.02O2Adding the primary sintered finished product into deionized water according to the mass ratio of water to material of 1:1, stirring and washing for 60min, wherein the stirring linear speed is 900 rpm; washing with water, performing suction filtration and separation, and drying at 150 ℃ for 4h to obtain LiNi0.91Co0.07W0.02O2And (3) a matrix cathode material.
And step 3: carrying out ball milling and mixing on the matrix anode material and the coating agent boric acid-yttrium oxide, wherein the boric acid accounts for 0.34 wt% of the matrix anode material, the yttrium oxide accounts for 0.05 wt% of the matrix anode material, the mass ratio of ball materials is 1.5:1 during ball milling, and the rotating speed is 1000 rpm. Then carrying out secondary sintering in an oxygen atmosphere to obtain the LiNi coated with the boron-yttrium composite0.91Co0.07W0.02O2The secondary sintering temperature is 350 ℃, the heat preservation time is 6 hours, the oxygen content is more than 90 percent, and the pressure is 37 +/-3 Pa.
Composite coated LiNi prepared in this example0.91Co0.07W0.02O2The discharge specific capacity of the cathode material finished button cell under 0.1C multiplying power is 210.6mAh/g, and the capacity retention rate is 92.3 percent after 100 cycles under 1C multiplying power. The total alkali content of the cathode material is 0.461%.
Example 5
Step 1: weighing LiNi with a certain massxCoyM1-x-yO2Precursor of molecular formula Ni0.96Mn0.04(OH)2Mixed with lithium hydroxide (LiOH. H)2O) and then sintering at the oxygen atmosphere to obtain LiNi0.96Mn0.04O2And sintering the finished product at one time. Wherein the mol ratio of the precursor to the lithium hydroxide is 1:1.03, the primary sintering temperature is 700 ℃, the heat preservation time is 8h, and the oxygen content isThe amount is more than 90%.
Step 2: weighing LiNi with a certain mass0.96Mn0.04O2Adding the primary sintered finished product into deionized water with a certain mass according to a water-material ratio of 1.5:1, stirring and washing for 30min at a stirring linear speed of 900 rmp; washing with water, separating by suction filtration, and drying at 120 deg.C for 4h to obtain LiNi0.96Mn0.04O2And (3) a matrix cathode material.
And step 3: carrying out ball milling and mixing on the matrix anode material and the coating agent boric acid-yttrium oxide, wherein the boric acid accounts for 0.34 wt% of the matrix anode material, the yttrium oxide accounts for 0.05 wt% of the matrix anode material, the mass ratio of ball materials is 1.5:1 during ball milling, and the rotating speed is 1000 rpm. Then carrying out secondary sintering in an oxygen atmosphere to obtain the LiNi coated with the boron-yttrium composite0.96Mn0.04O2The secondary sintering temperature is 265 ℃, the heat preservation time is 6 hours, the oxygen content is more than 90 percent, and the pressure is 30 +/-3 Pa.
The composite coated LiNi prepared by the implementation method0.96Mn0.04O2The discharge specific capacity of the finished button cell of the cathode material at 0.1C rate is 215.4mAh/g, the capacity retention rate of 100 cycles at 1C rate is 91.1%, and the total alkali content of the cathode material is 0.467%.
Example 6
Step 1: weighing LiNi with a certain massxCoyM1-x-yO2Precursor of molecular formula Ni0.80Co0.10Al0.10(OH)2Mixed with lithium hydroxide (LiOH. H)2O) and then sintering at the oxygen atmosphere to obtain LiNi0.80Co0.10Al0.10O2And sintering the finished product at one time. Wherein the molar ratio of the precursor to the lithium hydroxide is 1:1.03, the sintering temperature is 720 ℃, the heat preservation time is 8h, and the oxygen content is more than 90%.
Step 2: weighing LiNi with a certain mass0.80Co0.10Al0.10O2Adding a sintered finished product into deionized water with a certain mass according to a water-material ratio of 2:1, stirring and washing for 20min at a stirring linear speedIs 900 rmp; washing with water, separating by suction filtration, and drying at 120 deg.C for 4h to obtain LiNi0.80Co0.10Al0.10O2And (3) a matrix cathode material.
And step 3: carrying out ball milling and mixing on the matrix anode material and the coating agent boric acid-yttrium oxide, wherein the boric acid accounts for 0.45 wt% of the matrix anode material, the yttrium oxide accounts for 0.10 wt% of the matrix anode material, the mass ratio of ball materials is 1.5:1 during ball milling, and the rotating speed is 1000 rpm. Then carrying out secondary sintering in an oxygen atmosphere to obtain the LiNi coated with the boron-yttrium composite0.80Co0.10Al0.10O2The secondary sintering temperature is 300 ℃, the heat preservation time is 2 hours, the oxygen content is more than 90 percent, and the pressure is 25 +/-3 Pa.
Composite coated LiNi prepared in this example0.80Co0.10Al0.10O2The discharge specific capacity of the finished button cell of the cathode material at 0.1C multiplying power is 202.4mAh/g, the capacity retention rate of 100 cycles at 1C multiplying power is 90.2%, and the total alkali content of the cathode material is 0.487%.
Example 7
Step 1: weighing LiNi with a certain massxCoyM1-x-yO2Precursor of molecular formula Ni0.91Co0.06Mg0.03(OH)2Mixed with lithium hydroxide (LiOH. H)2O) and then sintering at the oxygen atmosphere to obtain LiNi0.91Co0.06Mg0.03O2And sintering the finished product at one time. Wherein the molar ratio of the precursor to the lithium hydroxide is 1:1.03, the sintering temperature is 705 ℃, the heat preservation time is 12h, and the oxygen content is more than 90%.
Step 2: weighing LiNi with a certain mass0.91Co0.06Mg0.03O2And adding the primary sintered finished product into deionized water with a certain mass according to the water-material ratio of 1:1, stirring and washing for 30min, wherein the stirring linear speed is 900 rmp. Washing with water, separating by suction filtration, and drying at 130 deg.C for 4h to obtain LiNi0.91Co0.06Mg0.03O2And (3) a matrix cathode material.
And step 3: carrying out ball milling and mixing on the matrix anode material and the coating agent boric acid-yttrium oxide, wherein the boric acid accounts for 0.68 wt% of the matrix anode material, the yttrium oxide accounts for 0.06 wt% of the matrix anode material, the mass ratio of ball materials is 1.5:1 during ball milling, and the rotating speed is 1000 rpm. Then carrying out secondary sintering in an oxygen atmosphere to obtain the LiNi coated with the boron-yttrium composite0.91Co0.06Mg0.03O2The secondary sintering temperature is 250 ℃, the heat preservation time is 4 hours, the oxygen content is more than 90 percent, and the pressure is 25 +/-3 Pa.
Co-coated LiNi prepared in this example0.91Co0.06Mg0.03O2The discharge specific capacity of the finished button cell of the cathode material at 0.1C multiplying power is 212.4mAh/g, the capacity retention rate of 100 cycles at 1C multiplying power is 90.9%, and the total alkali content of the cathode material is 0.453%.
Table 1 shows LiNi compositely coated with boron and yttrium obtained in examples 1 to 7 of the present inventionxCoyM1-x-yO2Total alkali LiOH/Li of positive electrode material2CO3And (6) testing the value.
TABLE 1 Total alkali LiOH/Li of cathode materials2CO3Test value
Figure BDA0002787745760000091
As can be seen from table 1, the total base numbers of the samples in the examples are all within 0.5%, which is beneficial to maintaining low viscosity of the slurry during the slurry preparation process of the positive electrode material, thereby improving the coating uniformity of the slurry, improving the processability of the positive electrode material, and improving the performance of the battery.
Fig. 1 shows an SEM image of a sample of example 3 at a magnification of 30K, and it can be seen from fig. 1 that the composite coating layer on the surface of the positive electrode material is uniformly distributed, because boric acid has good fluxing property, the composite coating layer can be more uniformly distributed, corrosion and dissolution of the electrolyte to the surface of the positive electrode material are effectively prevented, and the electrochemical stability and cycle performance of the positive electrode material are improved.
Fig. 2 shows the first charge and discharge curve at 0.1C rate for the sample of example 3. As can be seen from fig. 2, the first specific discharge capacity of the positive electrode material is 217.4mAh/g, and the first efficiency is as high as 90.2%, which is beneficial to the development of the capacity of the positive electrode material due to the good conductivity of the composite coating layer.
FIG. 3 shows the cycling profile of the sample of example 3 at 1C rate for 100 cycles. As can be seen from fig. 3, the capacity retention ratio of the positive electrode material after 100 cycles was 93.7%, indicating that the obtained battery had excellent cycle performance.
Fig. 4 shows the cycling curve of the sample pouch cell of example 3 cycled 800 cycles at 1C rate. As can be seen from fig. 4, the capacity retention rate of the cathode material after 800 cycles is 81.7%, and the cathode material has a better cycle performance, which is beneficial to the evenly distributed composite coating layer, and can effectively prevent the electrolyte from corroding the surface of the material, and improve the electrochemical stability and cycle performance of the material.

Claims (10)

1. The boron-yttrium composite coated high-nickel cathode material is characterized by comprising a matrix cathode material and a boron-yttrium composite coating layer coated on the matrix cathode material, wherein the molecular formula of the matrix cathode material is LiNixCoyM1-x-yO2Wherein x is more than or equal to 0.80 and less than or equal to 0.96, y is more than or equal to 0.00 and less than or equal to 0.11, x + y is less than or equal to 1, and M is one of Al, Mn, W and Mg; the boron yttrium composite cladding layer comprises yttrium oxide and a lithiated layer containing boric acid.
2. The boron-yttrium composite coated high-nickel cathode material as claimed in claim 1, wherein the boric acid accounts for 0.34 wt% -0.68 wt% of the matrix cathode material; the weight percentage of yttrium oxide in the matrix anode material is 0.05 wt% -0.20 wt%; the boric acid is 2000 meshes, and the yttrium oxide is in a nanometer level.
3. The boron-yttrium composite coated high-nickel cathode material as claimed in claim 1, wherein the weight percentage of boron element in the boron-yttrium composite coating layer in the matrix cathode material is 0.06 wt% -0.12 wt%; the weight percentage of yttrium element in the matrix anode material is 0.04 wt% -0.16 wt%.
4. The preparation method of the boron-yttrium composite coated high-nickel cathode material is characterized by comprising the following steps of:
s1, mixing the high-nickel anode material precursor with a lithium source, and sintering for the first time to obtain LiNixCoyM1-x-yO2Primary sintering to obtain a finished product;
s2, obtaining LiNi for the step S1xCoyM1-x-yO2Washing, separating and drying the primary sintered product to obtain a matrix cathode material;
and S3, mixing the matrix positive electrode material obtained in the step S2 with a coating agent boric acid-yttrium oxide, and performing secondary sintering to obtain the boron-yttrium composite coating positive electrode material.
5. The method for preparing a boron-yttrium composite coated high-nickel cathode material as claimed in claim 4, wherein in step S1, the molecular formula of the precursor of the high-nickel cathode material is NixCoyM1-x-y(OH)2The lithium source is lithium hydroxide monohydrate, and the molecular formula of the lithium hydroxide monohydrate is LiOH & H2O; the molar ratio of the precursor to the lithium hydroxide monohydrate is 1 (1-1.05).
6. The method for preparing a boron-yttrium composite coated high-nickel cathode material according to claim 4, wherein in the step S1, the primary sintering is performed in an oxygen atmosphere, the temperature is 680-780 ℃, the holding time is 8-16 h, and the oxygen content in the oxygen atmosphere is more than 90%.
7. The method for preparing a boron-yttrium composite coated high-nickel cathode material according to claim 4, wherein in step S2, LiNi is usedxCoyM1-x-yO2Washing the primary sintered product with deionized water, wherein the deionized water and LiNi are used for washingxCoyM1-x-yO2The mass ratio of the primary sintered finished product is (1-3) to 1; the water washing is stirring water washing, the stirring water washing time is 15min-60min, and the stirring linear speed is 900 rpm.
8. The method for preparing a boron-yttrium composite coated high-nickel cathode material according to claim 4, wherein in the step S2, the separation is suction filtration separation, the drying temperature is 100-150 ℃, and the drying time is 4-10 h.
9. The method according to claim 4, wherein in step S3, the matrix positive electrode material and the coating agent boric acid-yttrium oxide are mixed by a ball milling process, wherein the mass ratio of the balls to the materials is 1.5:1, and the rotation speed is 1000 rpm.
10. The method for preparing the boron-yttrium composite coated high-nickel cathode material according to claim 4, wherein the secondary sintering is performed in an oxygen atmosphere, the oxygen content is greater than 90%, the pressure is 20Pa-40Pa, the temperature of the secondary sintering is 250 ℃ -350 ℃, and the holding time is 2h-10 h.
CN202011304057.2A 2020-11-19 2020-11-19 Boron-yttrium composite coated high-nickel cathode material and preparation method thereof Pending CN112397700A (en)

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