CN108123122B

CN108123122B - NCM622 positive electrode material coating modification method

Info

Publication number: CN108123122B
Application number: CN201711375830.2A
Authority: CN
Inventors: 孙琦; 孙慧英; 尹元; 张姝
Original assignee: QINGDAO QIANYUN HIGH-TECH NEW MATERIAL CO LTD
Current assignee: QINGDAO QIANYUN HIGH-TECH NEW MATERIAL CO LTD
Priority date: 2017-12-19
Filing date: 2017-12-19
Publication date: 2020-06-19
Anticipated expiration: 2037-12-19
Also published as: CN108123122A

Abstract

The invention relates to a coating modification method of an NCM622 positive electrode material, and belongs to the technical field of electrode material preparation. The invention comprises the following steps: 1) coating: mixing nickel-cobalt-manganese ternary cathode material powder with a dispersing agent, adding alumina sol, and reacting at constant temperature; 2) washing with water: adding the stirred material and water with equal weight into a stirring tank, and stirring to obtain slurry; 3) and (3) suction filtration: pumping the fully stirred slurry into a suction filtration tank for suction filtration; 4) drying: and putting the filtered material into a bipyramid drying tank for drying to obtain the aluminum-coated ternary battery anode material. The invention reduces the washing cost in the steps of washing and drying, has simpler washing, high suction filtration speed and high efficiency, improves the productivity by more than 2 times, improves the production efficiency of the power type ternary cathode material, and ensures that the performance of the power type ternary cathode material is not influenced.

Description

NCM622 positive electrode material coating modification method

Technical Field

The invention relates to a coating modification method of an NCM622 positive electrode material, and belongs to the technical field of electrode material preparation.

Background

With the development of new energy automobiles, the demand for high-capacity high-cycle ternary materials is sharply increased. The industrial layouts 622 and 811 are widely performed by various manufacturers of household battery materials. The currently known 622 power type ternary cathode material is relatively complex in production process and low in efficiency, so that the productivity is low and the consumed time is long. 622 ternary positive electrode products with excellent performance can be obtained through small-scale production, but large-scale industrial production is difficult, and the cost of industrial production is high.

Disclosure of Invention

The invention aims to overcome the defects that the conventional ternary cathode material is small in production capacity and cannot give consideration to performance when the capacity is expanded, and provides a coating modification method of an NCM622 cathode material.

The invention is realized by adopting the following technical scheme:

a coating modification method of an NCM622 positive electrode material comprises the following steps:

1) coating: mixing nickel-cobalt-manganese ternary cathode material powder with a dispersing agent, adding an aqueous solution of alumina sol, and reacting at constant temperature;

2) washing with water: adding the stirred material and water with equal weight into a stirring tank, and stirring to obtain slurry;

3) and (3) suction filtration: pumping the fully stirred slurry into a suction filtration tank for suction filtration until no water flows out of a drainage pipeline;

4) drying: and putting the filtered material into a double-cone drying tank for drying until no agglomeration exists, thereby obtaining the aluminum-coated ternary battery anode material.

The step 1) comprises the following mixed materials in percentage by mass: the aqueous solution of the aluminum sol was mixed at a ratio of 1: 0.915.

The dispersing agent is deionized water.

The temperature of the constant-temperature reaction in the step 1) is 35-40 ℃.

The stirring time of the step 2) is 20 minutes.

The temperature of the oil in the double-cone drying tank in the step 4) is 175-185 ℃.

And 3) the suction filtration equipment in the step 3) is negative pressure suction filtration equipment, and the suction filtration time is 0.5 h.

The step 3) further comprises a cleaning step: and after the slurry is pumped into the suction filtration tank, cleaning the stirring tank by using water, and pumping the cleaning slurry into the suction filtration tank.

The NCM battery positive electrode material is prepared by the preparation method, and after secondary sintering and impact, the particle size is D10-6-9, and D50-11.5-13.8.

The positive electrode of the NCM battery comprises a ternary positive electrode material prepared by a NCM622 positive electrode material coating modification method.

The invention has the beneficial effects that:

(1) according to the NCM622 positive electrode material coating modification method, a special proportion of aluminum sol and materials is adopted, the coating effect is better, and the cycle performance of the battery material is improved to a great extent.

(2) According to the NCM622 positive electrode material coating modification method, the washing cost is reduced in the processes of washing and drying, the washing is simpler, the suction filtration speed is high, the efficiency is high, the productivity is improved by more than 2 times, the production efficiency of the power type ternary positive electrode material is improved, and the performance is not influenced.

(3) According to the NCM622 positive electrode material coating modification method, the waste water after washing can be recycled after being treated, so that the cost is further reduced, and the environment is protected.

Drawings

Fig. 1 is a charge-discharge curve diagram at a 1C magnification of the final synthetic product.

Fig. 2 is a cycle plot at 1C magnification of the final synthetic product.

Fig. 3 is a graph of cycle number for different magnifications of the final composite product.

FIG. 4 is one of the scanning electron micrographs (1000X) of the final composite product.

FIG. 5 is a second scanning electron micrograph (3000 times) of the final composite product.

FIG. 6 is a three (5000 times) scanning electron micrograph of the final composite product.

FIG. 7 is a scanning electron micrograph of the final synthesized product of four times (10000 times).

Detailed Description

The invention will be further explained with reference to the drawings.

The invention relates to a 622 power type NCM622 positive electrode material coating modification method, which comprises the following steps:

1) coating: mixing nickel-cobalt-manganese ternary positive electrode material powder with deionized water according to the mass ratio of 1:1, adding alumina sol (manufacturer: Dalisno), and reacting at constant temperature of 35 ℃.

2) Washing with water: adding tap water (the upper edge of the scale corresponds to the water level line of 450Kg of material) with the same weight as the material into the stirring tank, starting stirring, adding the material, washing with water and stirring for 20 minutes. The material amount of each time of water washing is controlled to be 500-1000 Kg.

After the stirring is finished, the air pump is opened, the slurry is pumped into the suction filtration tank, then 10Kg of tap water is used for cleaning the stirring tank, and the cleaning slurry is pumped into the suction filtration tank together.

3) And (3) suction filtration: and (4) adopting negative pressure suction filtration equipment, opening a cover plate of the suction filtration tank, starting suction filtration, and observing that filtrate is required to be free of turbidity. The pumping filtration time is 0.5-1 hour until the qualified standard of pumping filtration is reached: the surface of the material in the suction filtration tank has cracks and no accumulated water; no water flows out of a water outlet of the suction filtration tank; and (3) inserting the material rake into the material, wherein the suction filtration is qualified when no obvious water stain exists, and otherwise, the suction filtration is prolonged by 0.5 hour until the suction filtration meets the standard.

And after the suction filtration is qualified, pushing the trolley into the lower part of the suction filtration tank, placing a grid sieve (the grid size is 2-3cm), crushing the materials through the grid sieve, putting the crushed materials into the trolley, cleaning the materials in the tank by using a rake, and sieving the auxiliary materials.

4) Drying: setting the oil temperature of the double-cone dryer to 180 ℃, and filling the filtered material into a drying tank; feeding the two-pot secondary material into a double-cone drying tank, then closing a feeding port of the drying tank, setting the time for 0.5h after confirming that the feeding port is fastened, and starting drying and rotating.

And after the set time is reached, opening the tank opening, sampling to confirm the material drying standard, and if the material powder is not qualified in drying, prolonging the drying time by taking 0.5h as a unit until the drying standard is met. Two-pot 622D combined drying time: 1 h; three-pot 622D combined drying time: and (4) 1.2 h.

Table 1: electrochemical performance testing of the final product

Performance of	Numerical value	Unit of	Test method
				0.1C specific discharge capacity	＞175	mAh·g^-1	Button cell
Specific discharge capacity of 1C	＞165	mAh·g^-1	All-electric
				Normal temperature circulation 1000 weeks/1C	＞93.8	％	All-electric

After impacting a 622 twice-sintered semi-finished product, controlling the particle size to be 6-9 (D10) and 11.5-13.8 (D50), and mixing the following materials: the aqueous solution of the aluminum sol was mixed at a ratio (mass ratio) of 1:0.915, and then washed with water. The special proportion is different from the prior art that multiple times of water washing is needed, and a good coating effect can be obtained only by one time of water washing (see figures 4-7), so that the efficiency is doubled. Under the condition of not influencing the material capacity, the charge-discharge cycle stability of the material is improved (as shown in figures 1-3 and table 1), and as can be seen from figure 1, the charge-discharge of the final synthetic product can be maintained for more than 6500 s. As can be seen from fig. 2, the final synthetic product has high cycle performance: the capacity retention rate is 97.23 percent after 65 times of circulation at 1C. As can be seen from FIG. 3, the final product has excellent rate capability, a capacity of about 140mAh/g is still obtained at 5C, and the retention rate at 1C recovery after high-rate charge and discharge is 97% or more. According to the test result, the production expanding mode improves the production efficiency, but does not affect the performance of the product. Is suitable for industrialized popularization and large-scale production.

Of course, the foregoing is only a preferred embodiment of the invention and should not be taken as limiting the scope of the embodiments of the invention. The present invention is not limited to the above examples, and equivalent changes and modifications made by those skilled in the art within the spirit and scope of the present invention should be construed as being included in the scope of the present invention.

Claims

1. A NCM622 positive electrode material coating modification method is characterized in that: the method comprises the following steps:

1) coating: mixing nickel-cobalt-manganese ternary cathode material powder with a dispersing agent, adding alumina sol, and reacting at constant temperature;

3) and (3) suction filtration: pumping the fully stirred slurry into a suction filtration tank for suction filtration;

4) drying: putting the filtered material into a double-cone drying tank for drying to obtain an aluminum-coated ternary battery positive electrode material;

the step 1) is to mix the materials according to the mass ratio: the aqueous solution of the aluminum sol was mixed at a ratio of 1: 0.915.

2. The NCM622 positive electrode material coating modification method according to claim 1, characterized in that: the dispersing agent is deionized water.

3. The NCM622 positive electrode material coating modification method according to claim 1, characterized in that: the temperature of the constant-temperature reaction in the step 1) is 35-40 ℃.

4. The NCM622 positive electrode material coating modification method according to claim 1, characterized in that: the stirring time of the step 2) is 20 minutes.

5. The NCM622 positive electrode material coating modification method according to claim 1, characterized in that: the temperature of the oil in the double-cone drying tank in the step 4) is 175-185 ℃.

6. The NCM622 positive electrode material coating modification method according to claim 1, characterized in that: and 3) the suction filtration equipment in the step 3) is negative pressure suction filtration equipment, and the suction filtration time is 0.5 h.

7. The NCM622 positive electrode material coating modification method according to claim 1, characterized in that: the step 3) further comprises a cleaning step: and after the slurry is pumped into the suction filtration tank, cleaning the stirring tank by using water, and pumping the cleaning slurry into the suction filtration tank.

8. An NCM battery positive electrode material, which is prepared by the coating modification method of any one of claims 1 to 7, and has a particle size D10-6-9 and D50-11.5-13.8 after secondary sintering and impact.

9. A positive electrode of an NCM battery, characterized in that the positive electrode comprises the NCM positive electrode material prepared by the NCM622 positive electrode material coating modification method of claim 8.