CN111129465A - Preparation method of cathode material for efficiently improving lithium storage performance of ternary cathode material - Google Patents

Preparation method of cathode material for efficiently improving lithium storage performance of ternary cathode material Download PDF

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CN111129465A
CN111129465A CN201911397071.9A CN201911397071A CN111129465A CN 111129465 A CN111129465 A CN 111129465A CN 201911397071 A CN201911397071 A CN 201911397071A CN 111129465 A CN111129465 A CN 111129465A
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cathode material
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storage performance
lithium storage
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李昱
周航
陈良丹
吴亮
刘婧
陈丽华
王洪恩
苏宝连
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Wuhan University of Technology WUT
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
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    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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Abstract

The invention discloses a method for preparing a cathode material for efficiently improving the lithium storage performance of a ternary cathode material0.6Co0.2Mn0.2(OH)2Then the precursor is mixed with excess LiOH.H2And performing two-stage calcination reaction in a muffle furnace after mixing the O, wherein the temperature of the first-stage calcination reaction is 450-500 ℃, and the temperature of the second-stage calcination reaction is 700-800 ℃. Finally obtaining the product LiNi0.6Co0.2Mn0.2O2(NCM622) exhibiting excellent lithium storage performance when applied as a positive electrode of a lithium ion battery. The invention has the advantages of wide raw material source, simple preparation process and low cost, and is suitable for popularization and application.

Description

Preparation method of cathode material for efficiently improving lithium storage performance of ternary cathode material
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a preparation method of a cathode material for efficiently improving the lithium storage performance of a ternary cathode material.
Background
Rechargeable lithium ion batteries are widely used in electric vehicles and energy storage devices for renewable energy sources due to their characteristics of high energy, high power, and long cycle life. In order to meet the demand for higher energy density, in recent years, ternary high nickel layered LiNixCoyMn1-x-yO2(x.gtoreq.0.6) cathode materials are of great interest because of their high specific capacity, low cost and environmental friendliness, among which LiNi0.6Co0.2Mn0.2O2(NCM622) has been industrially produced and is considered to be one of the most promising positive electrode materials.
However, at present, the high nickel ternary cathode material still faces a plurality of problems: firstly, along with the increase of nickel content, the stability of the anode material is reduced, and the main expression form is the capacity loss of cyclic charge and discharge; secondly, in the high-voltage charging and discharging process, the high-potential transition metal ions cause the continuous oxidative decomposition of the electrolyte, the mixed discharging degree of lithium and nickel is intensified, the rapid attenuation of the capacity is caused, and the cycle life of the battery is finally reduced; third, commercial NCM622 typically uses battery grade Li2CO3When Li is used as the lithium source2CO3When the lithium ion battery is used as a lithium source, incomplete decomposition is often caused by insufficient calcination temperature, excessive free lithium on the surface of a positive electrode material and too strong alkalinity influence product performance, and Li2CO3Is generally produced by using LiOH as a raw material, and has higher cost. LiOH. H2O has a low melting point and low cost, and is considered to be one of the most popular lithium source materials. The invention intends to adopt LiOH. H2O is used as a lithium source, and a preparation method of the cathode material for efficiently improving the lithium storage performance of the ternary cathode material is designed.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to provide a method for preparing a cathode material for efficiently improving the lithium storage performance of a ternary cathode material, wherein sulfates of Ni, Co and Mn are used as raw materials, and a coprecipitation method is used for obtaining a spherical precursor Ni0.6Co0.2Mn0.2(OH)2Then the precursor is reacted with LiOH. H2And carrying out calcination reaction in a muffle furnace after mixing the O to finally obtain the NCM622 cathode material.
A preparation method of a cathode material for efficiently improving the lithium storage performance of a ternary cathode material is characterized by comprising the following steps:
step 1, mixing NiSO4·6H2O、CoSO4·7H2O、MnSO4·H2Placing O in deionized water, stirring and dissolving to obtain a transition metal sulfate solution; placing NaOH particles into deionized water, and stirring and dissolving to obtain a sodium hydroxide solution; adding a certain amount of deionized water into the concentrated ammonia water, and adjusting the pH value of the concentrated ammonia water by adopting a pH meter to obtain an ammonia water solution.
And 2, placing the ammonia water solution obtained in the step 1 into a three-neck flask, heating and stirring the ammonia water solution in a nitrogen atmosphere, simultaneously dropwise adding the transition metal sulfate solution and the sodium hydroxide solution obtained in the step 1, and standing the mixture after the reaction is completed to obtain a suspension.
Step 3, washing the suspension obtained in the step 2 with deionized water for multiple times, centrifugally separating, and then transferring to an oven for drying to obtain a precursor Ni0.6Co0.2Mn0.2(OH)2。
Step 4, mixing the precursor obtained in the step 3 with LiOH & H2Mixing, grinding and uniformly mixing O, transferring the mixture into a muffle furnace for two-stage calcination reactionTo finally obtain LiNi0.6Co0.2Mn0.2O2I.e., NCM622 positive electrode material.
In said step 1, NiSO4·6H2O、CoSO4·7H2O and MnSO4·H2The molar ratio of O is 6:2:2, and the concentration of the prepared solution is 1 mol.L-1-2mol·L-1And the stirring time is 10-25 min.
In the step 1, the molar ratio of NaOH to transition metal sulfate is 2: 1; the concentration of the NaOH solution is 2 mol.L-1-4mol·L-1And the stirring time is 10-25 min.
In the step 1, the pH value of the prepared ammonia water solution is 11-12.
In the step 2, the transition metal sulfate solution and the sodium hydroxide solution are respectively added dropwise at the same speed, and the dropwise addition is completed within 25-30 min.
In the step 2, the heating temperature is 40-60 ℃, the stirring speed is 1500r/min, the reaction time is 10-12h, the aging time is 10-12h after the reaction, the temperature of the oven is 70-80 ℃, and the drying time is 12-36 h.
In the step 3, the centrifugal separation times are 3-5 times, the rotating speed is 6000-.
In the step 4, precursor Ni0.6Co0.2Mn0.2(OH)2With LiOH. H2The molar ratio of O is 1:1.03-1: 1.08.
In the step 4, the first stage calcination temperature is 450-500 ℃, the time is 5-7h, the calcination temperature rise speed is 3-5 ℃/min, the second stage calcination temperature is 700-800 ℃, the time is 12-20h, and the calcination temperature rise speed is 3-5 ℃/min.
The method of the invention needs fewer steps, the used raw materials and equipment are simpler, and the prepared NCM622 positive electrode material has the characteristics of high specific capacity, good cycle performance and good rate performance, and compared with the prior art, the method of the invention has the following beneficial effects:
1) the NCM622 positive electrode material with the micron-sized particle size is prepared, the cycle stability and the cycle life of the ternary positive electrode material can be effectively improved, and the secondary particles are provided with the stacking holes, so that more active surfaces are provided for electrochemical reaction, the electrolyte can permeate into the positive electrode material particles, the utilization rate of the positive electrode material is improved, and the lithium storage performance of the lithium ion battery is further improved.
2) The invention has simple process and low requirement on experimental equipment. In the preparation process, this patent at first adopts aqueous ammonia solution as the base solution, and transition metal salt solution drips into aqueous ammonia solution's preparation method simultaneously with the sodium hydroxide solution with the same speed, and this preparation method not only can the pH value of stable system, can also make transition metal ion and hydroxyl ion fully precipitate, and the spherical precursor dispersion that finally makes is even, and the particle diameter is moderate, not only is favorable to further grinding mixing with the lithium source, can fully react with the lithium source when high temperature calcines moreover.
3) The invention adopts LiOH. H2O is used as a lithium source, the calcining temperature range is 700-800 ℃, the product has a better layered structure, the cost can be reduced, and the energy can be saved. The preparation process of the high nickel cathode material NCM622 is strict with the calcination temperature, and when the temperature is too low, the development of the layered structure of the material is not facilitated: when the temperature is too high, not only can serious lithium and nickel mixed discharge be caused, but also the structure of the material is damaged; the primary particles can also grow excessively, which is not beneficial to the diffusion kinetics of lithium ions; and a large amount of lithium can be volatilized, so that the specific capacity of the material is influenced. With Li commonly used in industry2CO3In contrast, the LiOH. H adopted in this patent2The melting point of O is low, the O can be fully melted and diffused at a low calcining temperature and can completely react with a precursor, the prepared anode material has a good layered structure (the splitting of a characteristic peak in an XRD (X-ray diffraction) diagram is obvious), the lithium-nickel mixed-discharge degree is low, the particle size is moderate, and the lithium storage performance is excellent.
Drawings
FIG. 1 is an XRD pattern of the NCM622 positive electrode materials obtained in examples 1-3 and comparative example 1;
FIG. 2 is a scanning electron micrograph of the positive electrode materials obtained in example 1 and comparative example 1 at a magnification of 20K, wherein A is a scanning image of the positive electrode material NCM622 obtained in example 1; b is a scanning image of the NCM622 positive electrode material obtained in comparative example 1;
FIG. 3 is a graph showing the cycle stability of the positive electrode materials obtained in examples 1 to 3 and comparative example 1 in a voltage range of 2.7 to 4.3V at a rate of 0.5C;
FIG. 4 is a graph showing the rate capability test of the positive electrode materials obtained in examples 1 to 3 and comparative example 1 in a voltage range of 2.7 to 4.3V.
Detailed Description
The technical scheme of the invention is further described in detail by the following embodiments and the accompanying drawings:
example 1
A preparation method of a cathode material for efficiently improving lithium storage performance of a ternary cathode material comprises the following steps:
1) mixing MnSO4·H2O、NiSO4·6H2O、CoSO4·7H26g of O (6:2:2) is put into 12.5ml of deionized water to be stirred and dissolved, so as to obtain a transition metal sulfate solution; 2g of NaOH particles are placed in 12.5ml of deionized water to be stirred and dissolved, and a sodium hydroxide solution is obtained; 1.5ml of strong ammonia water is taken and added with deionized water to adjust the PH value to 11.5, thus obtaining ammonia water solution.
2) Putting the ammonia water solution obtained in the step 1) into a three-neck flask, heating and stirring the ammonia water solution under the nitrogen atmosphere, respectively and simultaneously dropwise adding the transition metal sulfate solution and the sodium hydroxide solution obtained in the step 1), wherein the temperature is 50 ℃, the stirring speed is 1200r/min, the dropwise adding is completed in 25min, the reaction time is 12h, and after the reaction is completed, the ammonia water solution is aged for 12h to obtain a suspension.
3) And (3) carrying out 5 times of centrifugal separation on the suspension obtained in the step 2), adding deionized water during the 5 times of centrifugal separation, wherein the rotating speed is 7000r/min during each centrifugation, and the single centrifugation time is 7 min. Centrifugally transferring the mixture to an oven with the temperature of 80 ℃ for drying for 12h to obtain a precursor Ni0.6Co0.2Mn0.2(OH)2。
4) Mixing the precursor obtained in the step 3) with 5% excess LiOH & H2Mixing, grinding and uniformly mixing O, transferring to a muffle furnace, and calcining at 500 DEG CCalcining at 740 ℃ for 15h at the temperature of 5 ℃/min at the temperature rise speed of 5 ℃/min to finally obtain the LiNi0.6Co0.2Mn0.2O2(NCM622)。
5) The prepared anode material is applied to a lithium ion battery, and the method comprises the following specific steps: mixing the positive electrode material, the Super P and the PVDF according to the mass ratio of 8:1:1, dropwise adding a proper amount of N-methylpyrrolidone (NMP), grinding for about 30 minutes, uniformly coating the slurry on an aluminum foil, drying in an oven at 40 ℃ for 2 hours, placing in a vacuum drying oven, and drying at 120 ℃ for 12 hours. Then assembling a button cell, wherein a metal lithium sheet is adopted as a negative electrode, a polypropylene porous membrane is adopted as a diaphragm, and LiPF is adopted as electrolyte6The battery adopts a 2025 type button type battery, and electrochemical performance test is carried out in a voltage range of 2.7-4.3V.
The X-ray diffraction analysis of the product obtained in this example is shown in fig. 1, and it can be seen from the figure that the NCM622 positive electrode material has a relatively sharp diffraction peak, which indicates that the crystal form structure of the prepared ternary positive electrode material is complete, and the diffraction peak is represented by layered α -NaFeO2The type structure belongs to the R-3m space group. The two-component splitting peaks (006)/(102) and (108)/(110) are obvious in splitting, and the ternary cathode material prepared by the method has a good laminated structure. In addition, the product lithium nickel mixed-arrangement degree is low, the lithium nickel mixed-arrangement degree of the material is generally judged by the ratio of the peak intensity at the (003) plane to the peak intensity at the (104) plane, and when the ratio is more than 1.2, the lithium nickel mixed-arrangement phenomenon of the material is low. The peak intensity ratio of example 1 is 1.76, which is much greater than 1.2, and thus it is shown that the lithium-nickel mixed-discharge degree of the material is very low, which is beneficial to the material to maintain a stable layered structure in the lithium ion intercalation and deintercalation processes, and the migration of transition metal ions is reduced, and the mixed discharge of ions is inhibited, thereby improving the lithium storage performance of the cathode material.
A scanned graph of the product obtained in this example 1 is shown in fig. 2A, and it can be seen that the NCM622 positive electrode material is a sphere-like or spherical particle formed by agglomeration of primary particles, and this structure is beneficial to improving the stability of the positive electrode material in the cycle process. The primary particle size was about 200-300nm and the particle surface was smooth, indicating less surface residual alkali. In addition, a small number of stacking holes exist on the surface of the material, so that the anode material is in full contact with electrolyte, and the specific capacity is improved.
The cycle stability performance test chart of example 1 is shown in fig. 3, and the test result shows that, under the 0.5C multiplying power, the cycle stability of the product obtained in example 1 is good, the initial capacity is 153.5mAh/g, the coulomb efficiency of the first circle is 81.64%, the capacity is kept at 134.5mAh/g after 100 circles, and the capacity retention rate is 87.62%.
The rate performance test chart of example 1 is shown in fig. 4, and the test result shows that the prepared cathode material has better rate performance, the discharge capacity reaches 195mAh/g at the initial rate of 0.1C, and after charging and discharging at the rate of 5C, the cathode material returns to the cycle at the rate of 0.2C, and the specific discharge capacity can reach 170mAh/g, which indicates that the rate performance of the material is good.
Example 2:
1) mixing MnSO4·H2O、NiSO4·6H2O、CoSO4·7H26.21g of O (6:2:2) is put into 25ml of deionized water to be stirred and dissolved, so as to obtain a transition metal sulfate solution; 2g of NaOH particles are placed in 25ml of deionized water to be stirred and dissolved, and a sodium hydroxide solution is obtained; 1.5ml of strong ammonia water is taken and added with deionized water to adjust the PH value to 11, thus obtaining ammonia water solution.
2) Putting the ammonia water solution obtained in the step 1) into a three-neck flask, heating and stirring the ammonia water solution under the nitrogen atmosphere, respectively and simultaneously dropwise adding the transition metal sulfate solution and the sodium hydroxide solution obtained in the step 1), wherein the temperature is 40 ℃, the stirring speed is 1000r/min, 30min is completed dropwise adding, the reaction time is 10h, and after the reaction is completed, the ammonia water solution is aged for 10h to obtain a suspension.
3) And (3) carrying out 5 times of centrifugal separation on the suspension obtained in the step 2), adding deionized water during the 5 times of centrifugal separation, wherein the rotating speed is 8000r/min during each time of centrifugation, and the single centrifugation time is 8 min. Centrifugally transferring the mixture to an oven with the temperature of 80 ℃ for drying for 24 hours to obtain a precursor Ni0.6Co0.2Mn0.2(OH)2。
4) Mixing the precursor obtained in the step 3) with 3% excess LiOH & H2Mixing, grinding and mixing O uniformly, transferring into a muffle furnace, calcining at 450 deg.C for 5 hr at a heating rate of 3 deg.C/min at 700 deg.CContinuously calcining for 18h at the temperature rising speed of 3 ℃/min to finally obtain the LiNi0.6Co0.2Mn0.2O2(NCM622)。
5) Example 2X-ray diffraction analysis of the cathode Material As shown in FIG. 1, the diffraction peak was represented by α -NaFeO in a layered form2The type structure belongs to the R-3m space group. The splitting of the two components of the material is obvious in splitting of (006)/(102) and (108)/(110), the layered structure is good in development, the mixed-arrangement value of lithium and nickel in example 2 is 1.75 and is far greater than 1.2, and the mixed-arrangement degree of lithium and nickel of the material is low, so that the cycle performance of the material is improved.
6) And assembling the obtained positive electrode material and lithium metal into a button cell, and testing the electrochemical performance of the button cell in a voltage range of 2.7-4.3V. The test result shows that under the multiplying power of 0.5C, the product obtained in the example 2 has good circulation stability, the initial capacity is 160.6mAh/g, the coulomb efficiency of the first circle is 78.26%, the capacity is kept at 111.9mAh/g after 100 circles, and the capacity retention rate reaches 70%.
7) The rate performance test chart of example 2 is shown in fig. 4, and the test result shows that the prepared cathode material has better rate performance, the discharge capacity reaches 190mAh/g at the initial rate of 0.1C, and the discharge capacity returns to the cycle at the rate of 0.2C after the charge and discharge at the rate of 5C, and the discharge specific capacity can reach 158mAh/g, which indicates that the structure of the material is more stable in the cycle process.
Example 3:
1) mixing MnSO4·H2O、NiSO4·6H2O、CoSO4·7H26g of O (6:2:2) is put into 16.7ml of deionized water to be stirred and dissolved, so as to obtain a transition metal sulfate solution; 2g of NaOH particles are placed in 16.7ml of deionized water to be stirred and dissolved, and a sodium hydroxide solution is obtained; 1.5ml of strong ammonia water is taken and added with deionized water to adjust the PH value to 12, thus obtaining ammonia water solution.
2) Putting the ammonia water solution obtained in the step 1) into a three-neck flask, heating and stirring the ammonia water solution under the nitrogen atmosphere, respectively and simultaneously dropwise adding the transition metal sulfate solution and the sodium hydroxide solution obtained in the step 1), wherein the temperature is 70 ℃, the stirring speed is 1500r/min, the reaction time is 11h, and after the reaction is completed, the ammonia water solution is aged for 11h to obtain a suspension.
3) And (3) carrying out centrifugal separation on the suspension obtained in the step 2) for multiple times, adding deionized water during the centrifugal separation, wherein the rotating speed is 6000r/min during each centrifugation, and the single centrifugation time is 10 min. Centrifugally transferring the mixture to an oven with the temperature of 80 ℃ for drying for 18h to obtain a precursor Ni0.6Co0.2Mn0.2(OH)2。
4) Mixing the precursor obtained in the step 3) with 8% excess LiOH & H2Mixing, grinding and uniformly mixing O, transferring to a muffle furnace, calcining at 480 ℃ for 5h at a heating rate of 4 ℃/min, continuously calcining at 800 ℃ for 20h at a heating rate of 4 ℃/min, and finally obtaining LiNi0.6Co0.2Mn0.2O2(NCM622)。
5) Example 3X-ray diffraction analysis of the cathode Material As shown in FIG. 1, the diffraction peak was represented by α -NaFeO in a layered form2The type structure belongs to the R-3m space group. The splitting of the two components of splitting peaks (006)/(102) and (108)/(110) is obvious, the development of the layered structure is good, the mixed-arrangement value of lithium and nickel in example 3 is 1.71, which is much greater than 1.2, and the mixed-arrangement degree of lithium and nickel of the material is very low, which is beneficial to improving the cycle performance of the material.
6) And assembling the obtained positive electrode material and lithium metal into a button cell, and testing the electrochemical performance of the button cell in a voltage range of 2.7-4.3V. The test result shows that under the multiplying power of 0.5C, the product obtained in the example 2 has good circulation stability, the initial capacity is 164.7mAh/g, the coulomb efficiency of the first circle is 80.81%, the capacity is kept at 123.8mAh/g after 100 circles, and the capacity retention rate reaches 75.12%.
7) The rate performance test chart of example 3 is shown in fig. 4, and the test result shows that the prepared cathode material has better rate performance, the discharge capacity reaches 194mAh/g at the initial rate of 0.1C, and the discharge capacity returns to the cycle at the rate of 0.2C after the charge-discharge at the rate of 5C, and the discharge specific capacity can reach 160mAh/g, which indicates that the structure of the material is more stable in the cycle process.
Comparative example 1
Comparative example 1 the high performance lithium ion battery ternary positive electrode material LiNi0.6Co0.2Mn0.2O2(NCM622) was prepared in the same manner as in example 1, except for the difference in step 4)The lithium source in (1) is 5% excess Li2CO3。
The result of X-ray diffraction analysis of the product obtained in comparative example 1 is shown in FIG. 1, and the test result shows that the material has a relatively complete laminated structure. In addition, the product obtained in comparative example 1 had a (003)/(104) peak intensity ratio of 1.65, which is smaller than the lithium-nickel mixed value of the product obtained in example 1, indicating that LiOH. multidot.H was used2When O is used as a lithium source, the phenomenon of lithium-nickel mixed discharge of the material is more favorably inhibited. This is mainly because of Li2CO3Has high melting point, and can not be completely decomposed in the temperature range of 700-800 ℃, but LiOH H is used2And O can be fully melted and diffused when being used as a lithium source, the finally prepared cathode material lithium-nickel mixed-arrangement degree is low, the structure is more stable, the stability of the structure of the material in the process of lithium ion embedding and removing is facilitated, and the cycle performance of the material is improved.
The scanning image of the product obtained in the comparative example 1 is shown in fig. 2B, and it can be seen that the NCM622 positive electrode material is a sphere-like or spherical particle formed by the agglomeration of primary particles with a particle size of about 200-300nm, and this structure is favorable for improving the insertion and extraction of lithium ions and improving the diffusion kinetics of the positive electrode material. The material of comparative example 1 has fewer accumulated pores on the surface thereof as compared to example 1, and the electrolyte may not sufficiently react with the material, which may lower the utilization rate of the active material. Therefore, we predict that example 1 has a higher specific capacity. In addition, in comparative example 1, the surface of the positive electrode material particles of comparative example 1 is rougher, more residual alkali may exist on the surface, and more side reactions may occur in the positive electrode material during the circulation process, which may deteriorate the cycle performance of the material. In conclusion, we predict that example 1 has more excellent lithium storage properties.
The cyclic stability test chart of the material of the comparative example 1 is shown in figure 3, under the multiplying power of 0.5C, the initial capacity of the product obtained in the comparative example 1 is 144.7mAh/g, the coulombic efficiency of the first circle is 75.76%, the capacity is kept at 110mAh/g after 100 circles, and the capacity retention rate is 73.26%. The cycle performance of comparative example 1 was found when LiOH. H was used2When O is used as a lithium source, the synthesized positive electrode material has higher specific discharge capacity, higher first-turn coulombic efficiency and more excellent cycling stability。
The rate performance test chart of the material of comparative example 1 is shown in fig. 4, and the test result shows that the rate performance of the prepared cathode material is poor, the specific discharge capacity is only 175mAh/g at the initial rate of 0.1C, the cathode material returns to the cycle at the rate of 0.2C after charging and discharging at the rate of 5C, and the specific discharge capacity is only 122.7mAh/g, which indicates that the reversibility of the material is not good enough when the cathode material is cycled at a large rate. The rate performance of the example 1 material was found to be much better than that of the comparative example 1 material compared to the rate performance of the example 1 material. It is likely that the comparative example 1 material failed in structure when cycled at high rate, resulting in poor rate performance. Therefore, compared with the conventional Li source2CO3With LiOH. H2The anode material prepared by taking O as a lithium source has more excellent lithium storage performance, and the invention has more superiority.
In summary, the invention uses LiOH. H2High nickel ternary positive electrode material LiNi prepared by taking O as lithium source0.6Co0.2Mn0.2O2(NCM622) has a more stable layered structure, a lower degree of lithium-nickel segregation, and less surface residual alkali. Therefore, the prepared cathode material has higher specific capacity, more stable cycle performance and rate capability when being applied to the lithium ion battery. And the preparation method is simple, has lower cost, has more superiority compared with the prior art, and is suitable for popularization and application.
The raw materials listed in the invention, the upper and lower limits and interval values of the raw materials of the invention, and the upper and lower limits and interval values of the process parameters (such as temperature, time and the like) can all realize the invention, and the examples are not listed.
The protective scope of the present invention is not limited to the above-described embodiments, and it is apparent that various modifications and variations can be made to the present invention by those skilled in the art without departing from the scope and spirit of the present invention. It is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims (9)

1. A preparation method of a cathode material for efficiently improving the lithium storage performance of a ternary cathode material is characterized by comprising the following steps:
step 1, mixing NiSO4·6H2O、CoSO4·7H2O、MnSO4·H2Placing O in deionized water, stirring and dissolving to obtain a transition metal sulfate solution; placing NaOH particles into deionized water, and stirring and dissolving to obtain a sodium hydroxide solution; adding a certain amount of deionized water into the concentrated ammonia water, and adjusting the pH value of the concentrated ammonia water by adopting a pH meter to obtain an ammonia water solution;
step 2, placing the ammonia water solution obtained in the step 1 into a three-neck flask, heating and stirring the ammonia water solution in a nitrogen atmosphere, simultaneously dropwise adding the transition metal sulfate solution and the sodium hydroxide solution obtained in the step 1, and standing the mixture after the reaction is completed to obtain a suspension;
step 3, washing the suspension obtained in the step 2 with deionized water for multiple times, centrifugally separating, and then transferring to an oven for drying to obtain a precursor Ni0.6Co0.2Mn0.2(OH)2；
Step 4, mixing the precursor obtained in the step 3 with LiOH & H2Mixing, grinding and uniformly mixing O, transferring the mixture to a muffle furnace for two-stage calcination reaction to finally obtain LiNi0.6Co0.2Mn0.2O2I.e., NCM622 positive electrode material.
2. The preparation method of the cathode material for efficiently improving the lithium storage performance of the ternary cathode material as claimed in claim 1, wherein the preparation method comprises the following steps: in said step 1, NiSO4·6H2O、CoSO4·7H2O and MnSO4·H2The molar ratio of O is 6:2:2, and the concentration of the prepared solution is 1 mol.L-1-2mol·L-1And the stirring time is 10-25 min.
3. The preparation method of the cathode material for efficiently improving the lithium storage performance of the ternary cathode material as claimed in claim 1, wherein the preparation method comprises the following steps: in the step 1, the molar ratio of NaOH to transition metal sulfate is 2: 1; the concentration of the NaOH solution is 2 mol.L-1-4mol·L-1While stirringThe time interval is 10-25 min.
4. The preparation method of the cathode material for efficiently improving the lithium storage performance of the ternary cathode material as claimed in claim 1, wherein the preparation method comprises the following steps: in the step 1, the pH value of the prepared ammonia water solution is 11-12.
5. The preparation method of the cathode material for efficiently improving the lithium storage performance of the ternary cathode material as claimed in claim 1, wherein the preparation method comprises the following steps: in the step 2, the transition metal sulfate solution and the sodium hydroxide solution are respectively added dropwise at the same speed, and the dropwise addition is completed within 25-30 min.
6. The preparation method of the cathode material for efficiently improving the lithium storage performance of the ternary cathode material as claimed in claim 1, wherein the preparation method comprises the following steps: in the step 2, the heating temperature is 40-60 ℃, the stirring speed is 1500r/min, the reaction time is 10-12h, the aging time is 10-12h after the reaction, the temperature of the oven is 70-80 ℃, and the drying time is 12-36 h.
7. The preparation method of the cathode material for efficiently improving the lithium storage performance of the ternary cathode material as claimed in claim 1, wherein the preparation method comprises the following steps: in the step 3, the centrifugal separation times are 3-5 times, the rotating speed is 6000-.
8. The preparation method of the cathode material for efficiently improving the lithium storage performance of the ternary cathode material as claimed in claim 1, wherein the preparation method comprises the following steps: in the step 4, precursor Ni0.6Co0.2Mn0.2(OH)2With LiOH. H2The molar ratio of O is 1:1.03-1: 1.08.
9. The preparation method of the cathode material for efficiently improving the lithium storage performance of the ternary cathode material as claimed in claim 1, wherein the preparation method comprises the following steps: in the step 4, the first stage calcination temperature is 450-500 ℃, the time is 5-7h, the calcination temperature rise speed is 3-5 ℃/min, the second stage calcination temperature is 700-800 ℃, the time is 12-20h, and the calcination temperature rise speed is 3-5 ℃/min.
CN201911397071.9A 2019-12-30 2019-12-30 Preparation method of cathode material for efficiently improving lithium storage performance of ternary cathode material Pending CN111129465A (en)

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Publication number Priority date Publication date Assignee Title
CN112652748A (en) * 2020-12-22 2021-04-13 北京理工大学重庆创新中心 Self-lithium-supplement type single crystal nickel-cobalt-manganese composite ternary positive electrode material and preparation method thereof
CN112652748B (en) * 2020-12-22 2022-03-22 北京理工大学重庆创新中心 Self-lithium-supplement type single crystal nickel-cobalt-manganese composite ternary positive electrode material and preparation method thereof
CN113437379A (en) * 2021-06-24 2021-09-24 齐鲁理工学院 Method for recycling and regenerating waste ternary lithium battery
CN115490274A (en) * 2022-08-22 2022-12-20 西南交通大学 Preparation method of LiNi0.6Co0.2Mn0.2O2 and electrochemical performance test method thereof
RU2815267C1 (en) * 2023-09-21 2024-03-12 федеральное государственное бюджетное образовательное учреждение высшего образования "Национальный исследовательский университет "МЭИ" (ФГБОУ ВО "НИУ "МЭИ") Lithium battery cathode active mass manufacturing method

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