Blended lithium-ion battery cathode material, its preparation method, and lithium-ion battery

Abstract

The present invention relates to the field of lithium-ion batteries, and discloses a blended lithium-ion battery cathode material, a preparation method thereof, and a lithium-ion battery. The cathode material includes lithium cobaltate material and a multi-component material; the characteristic peaks (104) of the blended lithium-ion battery cathode material, the lithium cobaltate material, and the multi-component material obtained by XRD testing satisfy the following characteristics: (1) the characteristic peak C(104) corresponding to the (104) crystal plane of the lithium cobaltate material shows a double-peak distribution after peak separation; the characteristic peak N(104) corresponding to the (104) crystal plane of the multi-component material shows a double-peak distribution after peak separation. When the blended lithium-ion cathode material is subjected to X-ray diffraction testing, a special XRD pattern is presented. The cathode material has excellent tap density. When the blended lithium-ion battery cathode material is used in a lithium-ion battery, it exhibits excellent cycle life and low gas generation.

Description

Technical Field

[0001] The present invention relates to the field of lithium-ion batteries, and particularly to a blended lithium-ion battery cathode material, a preparation method thereof, and a lithium-ion battery. Background Art

[0002] Due to the rapid development of 3C electronic products, power tools, electric vehicles, and electrochemical energy storage devices, the market's requirements for the energy density, production cost control, cycle life, and safety performance of lithium-ion battery products are constantly increasing, which has stimulated a large amount of research and development work on high-performance lithium-ion batteries.

[0003] The performance of the cathode material plays a key role in the energy density, cycle life, safety, etc. of lithium-ion batteries, and at the same time occupies the highest part of the cost of lithium-ion batteries. Therefore, the research and improvement of lithium-ion battery cathode materials are very crucial.

[0004] Lithium cobalt oxide (LCO) materials have advantages such as high voltage platform and high tap density, but at the same time have disadvantages such as specific capacity, cycle life, and economy being inferior to those of multi-component (NCM) materials. If the advantages of both can be combined and utilized, the cost performance of lithium-ion batteries can be significantly improved, which is of great significance to the lithium-ion battery market.

[0005] Since there are obvious differences in tap density, electrolyte, voltage platform, etc. between LCO and NCM system materials during use, if LCO and conventional NCM materials are simply mixed and used, there will be problems such as difficult electrolyte compatibility and overcharging of NCM particles, further leading to adverse consequences such as a decrease in the battery cycle life and serious gas generation, and it is difficult to take into account the advantages of LCO and NCM materials. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problem that it is difficult to simultaneously exert the advantages of conventional LCO materials and NCM materials when they are blended, and to provide a blended lithium-ion battery cathode material, a preparation method thereof, and a lithium-ion battery. When the blended lithium-ion cathode material is subjected to X-ray diffraction testing, a special XRD pattern is presented. The cathode material has excellent tap density. When the blended lithium-ion battery cathode material is used in a lithium-ion battery, it exhibits excellent cycle life and low gas generation.

[0007] The first aspect of the present invention provides a blended lithium-ion battery cathode material, and the cathode material includes lithium cobalt oxide material and multi-component material;

[0008] The characteristic peak (104) of the blended lithium-ion battery cathode material, the lithium cobalt oxide material, and the multi-component material through XRD testing satisfies the following characteristics:

[0009] (1) The characteristic peak C(104) corresponding to the (104) crystal plane of the lithium cobaltate material shows a double-peak distribution after peak separation; the characteristic peak N(104) corresponding to the (104) crystal plane of the multi-component material shows a double-peak distribution after peak separation.

[0010] In the second aspect of the present invention, a method for preparing a blended lithium-ion battery cathode material is provided. The preparation method includes the following steps:

[0011] Step 1: Preparation of the lithium cobaltate material

[0012] (1) Mix the lithium cobaltate material precursor, the first lithium source, and optionally additive C1 to obtain mixture I;

[0013] (2) Subject mixture I to first calcination, cooling, crushing, and screening to obtain the lithium cobaltate material intermediate product CP;

[0014] (3) Mix the lithium cobaltate material intermediate product CP, optionally additive C2, and optionally additive C3 to obtain mixture II;

[0015] (4) Subject mixture II to first roasting, cooling, screening, and demagnetization to obtain the lithium cobaltate material;

[0016] Step 2: Preparation of the multi-component material

[0017] (5) Mix the multi-component material precursor, the second lithium source, and optionally additive N1 to obtain mixture III;

[0018] (6) Subject mixture III to second calcination, cooling, crushing, and screening to obtain the multi-component material intermediate product NP;

[0019] (7) Mix the multi-component material intermediate product NP, optionally additive N2, and optionally additive N3 to obtain mixture IV;

[0020] (8) Subject mixture IV to second roasting, cooling, screening, and demagnetization to obtain the multi-component material;

[0021] Step 3: Preparation of the blended lithium-ion battery cathode material

[0022] (9) Uniformly mix the lithium cobaltate material and the multi-component material, followed by screening and demagnetization to obtain the blended lithium-ion battery cathode material;

[0023] Wherein, the first roasting and the second roasting each independently include a first heating stage, a second heating stage, and a heat preservation stage;

[0024] And control the oxygen concentration in the atmosphere in the first heating stage to be less than the oxygen concentration in the atmosphere in the second heating stage; control the heating rate in the first heating stage to be greater than the heating rate in the second heating stage.

[0025] The third aspect of the present invention provides a preparation method of a blended lithium-ion battery cathode material, and the preparation method includes the following steps;

[0026] S1. Mix a lithium cobaltate material precursor, a first lithium source, and optionally an additive C1 to obtain a mixture I;

[0027] S2. Subject the mixture I to first calcination, cooling, crushing, and screening to obtain a lithium cobaltate material intermediate product CP;

[0028] S3. Mix a multi-component material precursor, a second lithium source, and optionally an additive N1 to obtain a mixture III;

[0029] S4. Subject the mixture III to second calcination, cooling, crushing, and screening to obtain a multi-component material intermediate product NP;

[0030] S5. Mix the lithium cobaltate material intermediate product CP, the multi-component material intermediate product NP, optionally an additive C3, optionally an additive N3, optionally an additive C2, and optionally an additive N2 to obtain a mixture V;

[0031] S6. Subject the mixture V to third calcination, cooling, screening, and demagnetization to obtain the blended lithium-ion battery cathode material;

[0032] Wherein, each of the first calcination and the second calcination independently includes a first heating stage, a second heating stage, and a heat preservation stage;

[0033] And control the oxygen concentration in the atmosphere in the first heating stage to be less than the oxygen concentration in the atmosphere in the second heating stage; control the heating rate in the first heating stage to be greater than the heating rate in the second heating stage.

[0034] The fourth aspect of the present invention provides a blended lithium-ion battery cathode material prepared by the above preparation method.

[0035] The fifth aspect of the present invention provides a lithium-ion battery, and the lithium-ion battery includes the above blended lithium-ion battery cathode material.

[0036] Through the above technical solutions, the blended lithium-ion battery cathode material, its preparation method, and the lithium-ion battery provided by the present invention obtain the following beneficial effects:

[0037] (1) When the blended lithium-ion battery cathode material provided by the present invention is subjected to X-ray diffraction testing, it presents a special XRD pattern. The cathode material with the characteristics of this special XRD pattern exhibits a high powder compaction density.

[0038] (2) When the blended lithium-ion battery cathode material provided by the present invention is used in a lithium-ion battery, it can significantly improve the cycle life, high-temperature storage performance, and safety of the lithium-ion battery (the high-temperature storage bulging rate is significantly reduced); further, when the blended lithium-ion battery cathode material provided by the present invention is used in a lithium-ion battery, it can significantly enlarge the voltage change range at the initial charging end and the discharging end of the lithium-ion battery, facilitating the battery management system (BMS) to accurately identify, manage, and control the battery cells.

[0039] (3) The cost of the blended lithium-ion battery cathode material provided by the present invention is significantly lower than that of the lithium cobaltate cathode material, and it has more excellent cost performance. Description of the Drawings

[0040] Figure 1 is the XRD pattern of the blended lithium-ion battery cathode material S1 prepared in Example 1;

[0041] Figure 2 is a schematic diagram of the XRD pattern of the blended lithium-ion battery cathode material S1 prepared in Example 1 after peak fitting;

[0042] Figure 3 is the XRD pattern of the blended lithium-ion battery cathode material S2 prepared in Example 2;

[0043] Figure 4 is the XRD pattern of the blended lithium-ion battery cathode material S3 prepared in Example 3;

[0044] Figure 5 is the XRD pattern of the blended lithium-ion battery cathode material D3 prepared in Comparative Example 3;

[0045] Figure 6 is the charge-discharge curve of the lithium-ion battery assembled with the cathode materials of Example 1 and Comparative Example 1. Detailed Embodiments

[0046] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values and individual point values of each range, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0047] The first aspect of the present invention provides a blended lithium-ion battery cathode material, which includes lithium cobaltate material and a multi-component material;

[0048] The characteristic peaks (104) of the blended lithium-ion battery cathode material, the lithium cobaltate material, and the multi-component material obtained by XRD testing satisfy the following characteristics:

[0049] (1) The characteristic peak C(104) corresponding to the (104) crystal plane of the lithium cobaltate material shows a double-peak distribution after peak separation; the characteristic peak N(104) corresponding to the (104) crystal plane of the multi-component material shows a double-peak distribution after peak separation.

[0050] In the present invention, C(104) represents the characteristic peak corresponding to the (104) crystal plane of the lithium cobaltate material, and N(104) represents the characteristic peak corresponding to the (104) crystal plane of the multi-component material.

[0051] The inventors of the present invention have found through research that since the tap density, voltage plateau, and voltage window of conventional NCM cathode materials are lower than those of LCO cathode materials, when they are blended with LCO materials, there are always problems such as low tap density and overcharging. The long-term overcharging state causes the layered structure of the NCM material to collapse rapidly, the material particles to be pulverized, and the side reaction with the electrolyte to intensify, resulting in accelerated decline of the cycle life and serious gas generation in the battery.

[0052] Furthermore, the inventors have found through research that by performing XRD testing on the blended lithium-ion battery cathode material, LCO material, and NCM material, it is found that when the characteristic peaks corresponding to the (104) crystal planes of the LCO material and the NCM material show a peak separation phenomenon or trend and have an obviously left-right asymmetric structure, the tap density and particle strength of the obtained blended lithium-ion battery cathode material are significantly improved. When it is used in a lithium-ion battery, it can significantly improve the cycle performance, high-temperature storage performance, and safety performance of the lithium-ion battery.

[0053] When performing XRD testing on the cathode material, the X-ray generated by the XRD equipment is the Kα ray corresponding to Cu, which is composed of Kα1 and Kα2 rays with fine wavelength differences, and the number of Kα1 is more than that of Kα2 (about twice that of Kα2). After diffraction by the conventional-structured NCM cathode material or LCO cathode material, the two characteristic diffraction peaks formed are basically all overlapped and cannot be effectively distinguished.

[0054] In the present invention, the inventors have found through research that by regulating the structures of NCM materials and / or LCO materials, after X-rays are diffracted by the improved NCM materials and / or LCO materials, the peak widths of the two characteristic diffraction peaks formed by Kα1 and Kα2 rays are significantly reduced. Furthermore, the characteristic diffraction peaks of Kα1 and Kα2 rays can be distinguished. However, due to their close positions, there is a partial overlap phenomenon. Therefore, finally, the characteristic peak corresponding to the (104) crystal plane shows a phenomenon or tendency of peak splitting.

[0055] Specifically, the XRD pattern of the blended lithium-ion battery cathode material S1 provided by the present invention is as Figure 1 shown. It can be seen from Figure 1 that the blended lithium-ion battery cathode material has two (104) characteristic peaks, namely N(104) and C(104), which are the characteristic peaks corresponding to the (104) crystal planes of NCM materials and LCO materials respectively; both the N(104) and C(104) peaks show a phenomenon or tendency of peak splitting, that is, the N(104) and C(104) characteristic peaks both show an obviously asymmetric structure on the left and right. Further, the schematic diagram of the XRD pattern of the blended lithium-ion battery cathode material S1 provided by the present invention after peak splitting is as Figure 2 shown. By performing peak splitting on the XRD pattern of the blended lithium-ion battery cathode material, the N(104) and C(104) characteristic peaks are respectively divided into two peaks, both of which can be divided into the first peak (A, on the left) and the second peak (B, on the right).

[0056] Furthermore, since the number of Kα1 rays is more than that of Kα2, the characteristic peak intensity formed by Kα1 is higher than that of Kα2, and the peak position of the characteristic diffraction peak formed by Kα2 is slightly higher than that of Kα1. Therefore, the peak height and peak area of the second peak (B, on the right) after peak splitting of the characteristic peak of the (104) crystal plane are both smaller than those of the first peak (A, on the left).

[0057] In the present invention, the peak position 2θ of the characteristic peak of the (104) crystal plane of the LCO material is 44.84° - 46°; the peak position of the characteristic peak of the (104) crystal plane of the NCM material is 43.50° - 44.84°.

[0058] Even further, the internal and surface structures of the NCM material in the blended lithium-ion battery cathode material provided by the present invention are more stable, and it has a higher compatibility with the electrolyte used in the LCO cathode material, can withstand a higher charging voltage, and can significantly improve problems such as reduced lifespan and increased gas generation when it is used in admixture with LCO. As a result, this blended lithium-ion battery cathode material has a high tap density and high voltage tolerance. When it is used in a lithium-ion battery, the cycle life and safety of the lithium-ion battery are significantly improved.

[0059] According to the present invention, based on the total weight of the blended lithium-ion battery cathode material, the weight ratio of the multi-component material is α;

[0060] The characteristic peaks (104) of the blended lithium-ion battery cathode material, the lithium cobaltate material, and the multi-component material measured by XRD satisfy the following characteristics:

[0061] (2) 7α 2 ≤ A N(104) / A C(104) ≤ 13α 2 , A N(104) is the peak area of the first peak after deconvolution of N(104), and A C104) is the peak area of the first peak after deconvolution of C(104);

[0062] (3) 6α 2 ≤ I AN / I AC ≤ 12α 2 , I AN is the peak intensity of the first peak after deconvolution of N(104), and I AC is the peak intensity of the first peak after deconvolution of C(104).

[0063] In the present invention, when A N(104) / A C(104) and I AN / I AC meet the above ranges, both the LCO material and the NCM material have relatively large grain sizes; at the same time, the grain size grading between the two is relatively moderate, and the particles can effectively fill each other, reducing the porosity. Finally, the blended lithium-ion battery cathode material containing the above LCO material and NCM material has a high tap density and structural stability. When used in a lithium-ion battery, it can significantly improve the cycle life and safety of the lithium-ion battery, etc.

[0064] Furthermore, 8α 2 ≤ A N(104) / A C(104) ≤ 12α 2 .

[0065] Furthermore, 7α 2 ≤ I AN / I AC ≤ 11α 2 .

[0066] According to the present invention, 0.05 ≤ α ≤ 0.9.

[0067] In the present invention, based on the total weight of the blended lithium-ion battery cathode material, when the dosage α of the multi-component material satisfies the above range, the proportion of the LCO material and the NCM material is appropriate, and it will not significantly affect the tap density of the blended lithium-ion battery cathode material and the voltage platform of the lithium-ion battery assembled from this cathode material due to excessive NCM material, nor will it affect the cost performance (price and capacity) of the blended lithium-ion battery cathode material due to excessive LCO material. Finally, the blended lithium-ion battery cathode material containing the above LCO material and NCM material has high tap density and structural stability. When it is used in a lithium-ion battery, it significantly improves the cost performance, cycle life, safety, etc. of the lithium-ion battery.

[0068] Further, 0.05 ≤ α ≤ 0.6, and more preferably, 0.1 ≤ α ≤ 0.5.

[0069] According to the present invention, the characteristic peaks (104) of the blended lithium-ion battery cathode material, the lithium cobalt oxide material, and the multi-component material obtained by XRD testing satisfy the following characteristics:

[0070] (4) 6α 2 ≤ B N(104) / B C(104) ≤ 12α 2 , B N(104) is the peak area of the second peak after peak deconvolution of N(104), and B C104) is the peak area of the second peak after peak deconvolution of C(104);

[0071] (5) 5α 2 ≤ I BN / I BC ≤ 11α 2 , I BN is the peak intensity of the second peak after peak deconvolution of N(104), and I BC is the peak intensity of the second peak after peak deconvolution of C(104).

[0072] In the present invention, when I BN / I BC and B N(104) / B C(104) satisfy the above range, both the LCO material and the NCM material have relatively high particle strength; at the same time, the particle strength matching between the two is appropriate. After the large and small particles are filled with each other, the stress between particles or inside particles can be effectively buffered, and the particles are difficult to crack or pulverize; finally, the blended lithium-ion battery cathode material containing the above LCO material and NCM material has high tap density and structural stability. When it is used in a lithium-ion battery, it significantly improves the cycle life and safety, etc. of the lithium-ion battery.

[0073] Further, 7α 2 ≤ BN(104) / B C(104) ≤11α 2 。

[0074] Furthermore, 6α 2 ≤I BN / I BC ≤10α 2 。

[0075] According to the present invention, the powder tap density of the blended lithium ion battery cathode material ≥ 3.8 g / cm 3 。

[0076] In the present invention, the blended lithium ion battery cathode material has a high powder tap density. When it is used in a lithium ion battery, it significantly improves the tap density and volume energy density of the lithium ion battery electrode sheet, etc.

[0077] Furthermore, the tap density of the blended lithium ion battery cathode material ≥ 4 g / cm 3 。

[0078] Lithium cobalt oxide material LCO

[0079] According to the present invention, the characteristic peak (104) of the lithium cobaltate material tested by XRD satisfies the following characteristics:

[0080] (i-C)1.8 ≤ I AC / I BC ≤ 2.4, I AC is the peak intensity of the first peak after the peak separation of C(104), I BC is the peak intensity of the second peak after the peak separation of C(104);

[0081] (ii-C)2 ≤ A C(104) / B C(104) ≤ 4, A C(104) is the peak area of the first peak after the peak separation of C(104), B C(104) is the peak area of the second peak after the peak separation of C(104).

[0082] In the present invention, when I AC / I BC and A C(104) / B C(104) meet the above ranges, it indicates that the LCO material has a relatively large grain size, a relatively complete grain structure, and a relatively high particle strength, making the blended lithium ion battery cathode material containing the above LCO material have a high tap density and structural stability. When it is used in a lithium ion battery, it significantly improves the cycle life and safety of the lithium ion battery, etc.

[0083] Furthermore, 1.9 ≤ I AC / IBC ≤2.3; 2.2 ≤ A C(104) / B C(104) ≤3.5.

[0084] According to the present invention, the grain size Size C of the (110) crystal plane obtained by XRD of the lithium cobalt oxide material satisfies:

[0085] In the present invention, when the grain size Size C of the (110) crystal plane satisfies the above range, it indicates that the LCO material has a large grain size, a small number of grain boundaries, and high particle strength, and can maintain the integrity of the grains under a relatively high pressure during the rolling process of the battery electrode sheet. Therefore, the tap density of the blended material containing the LCO material is significantly improved.

[0086] In the present invention, the grain size Size C of the (110) crystal plane of the lithium cobalt oxide material is calculated according to the full width at half maximum of the (110) peak in the XRD test of the LCO material and the Scherrer formula. The finally simplified calculation formula is SizeC = 98 / FWHM C(110) , where FWHM C(110) is the full width at half maximum of the (110) peak of the lithium cobalt oxide material.

[0087] Furthermore,

[0088] Multi-component material NCM

[0089] According to the present invention, the characteristic peak (104) of the multi-component material tested by XRD satisfies the following characteristics:

[0090] (i - N)1.9 ≤ I AN / I BN ≤2.5, I AN is the peak intensity of the first peak after the peak fitting of N(104), I BN is the peak intensity of the second peak after the peak fitting of N(104);

[0091] (ii - N)2 ≤ A N(104) / B N(104) ≤4, A N(104) is the peak area of the first peak after the peak fitting of N(104), B N(104) is the peak area of the second peak after the peak fitting of N(104).

[0092] In the present invention, when I AN / I BN and A N(104) / B N(104)When the above ranges are satisfied, it indicates that the NCM material has a large grain size, high particle strength, and low specific surface area, ultimately enabling the blended lithium-ion battery cathode material containing the above NCM material to have a high tap density, high structural stability, and low reactivity with the electrolyte. When used in a lithium-ion battery, it significantly improves the cycle life and safety of the lithium-ion battery, etc.

[0093] Further, 2 ≤ I AN / I BN ≤ 2.4; 2.5 ≤ A N(104) / B N(104) ≤ 3.5.

[0094] According to the present invention, the grain size SizeN of the (110) crystal plane obtained by XRD of the multi-component material satisfies:

[0095] In the present invention, when the grain size Size N of the (110) crystal plane satisfies the above range, it indicates that the NCM material has a large grain size, fewer grain boundaries, and high particle strength, and can maintain the integrity of the grains under the high particle expansion / contraction stress during the charge and discharge process of the battery. Therefore, the cycle life of the blended lithium-ion battery cathode material containing the NCM material is significantly improved.

[0096] In the present invention, the grain size Size N of the (110) crystal plane of the multi-component material is calculated based on the full width at half maximum of the (110) peak in the XRD test of the NCM material and the Scherrer formula. The finally simplified calculation formula is SizeN = 98 / FWHM N(110) , where FWHM N(110) is the full width at half maximum of the (110) peak of the multi-component material.

[0097] Further,

[0098] According to the present invention, the lithium cobaltate material has the composition shown in Formula I:

[0099] Li n1 Co a Al b M’ 1-a-b O 2 Formula I

[0100] Wherein, 0.9 ≤ n1 ≤ 1.1, 0.8 ≤ a1 < 0.99, 0 < b ≤ 0.1, 0 ≤ a2 ≤ 0.1, 0 ≤ 1 - a - b ≤ 0.05, a = a1 + a2;

[0101] M' is selected from at least one of Na, K, B, W, Mo, Rb, V, Ca, Al, Si, Hf, Ta, Y, Sr, Ba, Er, Mg, Ti, Zr, La, Ce, P, F, and Nb.

[0102] In the present invention, as shown in Formula I, the lithium cobalt oxide material not only contains the doping elements Al and M', and M' and Co can form a coating structure on the lithium cobalt oxide material, so that the material has high structural and surface interface stability, and the blended lithium ion battery cathode material containing the above LCO material has high structural stability. When it is used in a lithium ion battery, the cycle life and safety of the lithium ion battery are significantly improved.

[0103] Furthermore, 0.95 ≤ n1 ≤ 1.05, 0.85 ≤ a1 < 0.98, 0.001 ≤ b ≤ 0.08, 0 ≤ a2 ≤ 0.08, 0.001 ≤ 1 - a - b ≤ 0.02.

[0104] Furthermore, M' is selected from at least one of Na, K, B, Rb, Ca, Al, Mg, Sr, Ba, Zr, La, F, and Y.

[0105] According to the present invention, the multi-component material has the composition shown in Formula II:

[0106] Li n2 Ni x Co y Mn z M” 1-x-y-z O 2 ·βLiCo c Al 1-c O 2 Formula II;

[0107] Wherein, Li n2 Ni x Co y Mn z M” 1-x-y-z O 2 is the multi-component material matrix, LiCo c Al 1-c O 2 is the coating layer, 0 ≤ β ≤ 0.1;

[0108] Wherein, 0.9 ≤ n2 ≤ 1.3, 0 < x < 1, 0 ≤ y ≤ 0.5, 0 ≤ z ≤ 0.5, 0 ≤ 1 - x - y - z ≤ 0.02, 0.8 ≤ c ≤ 1;

[0109] M” is selected from at least one of Na, K, B, W, Mo, Rb, V, Ca, Al, Si, Hf, Ta, Y, Sr, Ba, Er, Mg, Ti, Zr, La, Ce, P, and Nb.

[0110] In the present invention, among the multi-component materials with the above composition, a material doped with the M'' element is used as the matrix, and a compound containing Co and Al is used as the coating layer on the surface (LCO coating layer structure). This can make the multi-component material have high structural stability and a low specific surface area. At the same time, the LCO coating layer structure on the surface has higher compatibility with the electrolyte system used in LCO materials, and can significantly reduce the reactivity between the NCM material and the electrolyte. Ultimately, the blended lithium-ion battery cathode material containing the above NCM material has high structural stability and low reactivity with the electrolyte. When it is used in a lithium-ion battery, the cycle life and safety of the lithium-ion battery are significantly improved, etc.

[0111] Further, 0.01 ≤ β ≤ 0.08.

[0112] Further, 1.0 ≤ n2 ≤ 1.2, 0.3 < x < 1, 0 ≤ y ≤ 0.3, 0 < z ≤ 0.4, 0.001 ≤ 1 - x - y - z ≤ 0.01, 0.9 ≤ c ≤ 0.99.

[0113] Further, M'' is selected from at least one of Na, K, B, Rb, Ca, Mg, Sr, Ba, Zr, La, and Y.

[0114] The blended lithium-ion battery cathode material provided by the present invention includes lithium cobaltate material and multi-component material. The first calcination in the preparation process of the lithium cobaltate material and the second calcination in the preparation process of the multi-component material each independently include a first heating stage, a second heating stage, and a heat preservation stage; and the oxygen concentration in the atmosphere of the first heating stage is controlled to be less than the oxygen concentration in the atmosphere of the second heating stage; the heating rate of the first heating stage is controlled to be greater than the heating rate of the second heating stage.

[0115] The second aspect of the present invention provides a preparation method for a blended lithium-ion battery cathode material, and the preparation method includes the following steps:

[0116] Step 1: Preparation of lithium cobaltate material

[0117] (1) Mix a lithium cobaltate material precursor, a first lithium source, and optionally an additive C1 to obtain a mixture I;

[0118] (2) Perform first calcination, cooling, crushing, and screening on the mixture I to obtain a lithium cobaltate material intermediate product CP;

[0119] (3) Mix the lithium cobaltate material intermediate product CP, optionally an additive C2, and optionally an additive C3 to obtain a mixture II;

[0120] (4) Subject the mixture II to first calcination, cooling, screening, and demagnetization to obtain the lithium cobaltate material;

[0121] Step 2: Preparation of the multi-component material

[0122] (5) Mix the multi-component material precursor, the second lithium source, and optionally additive N1 to obtain mixture III;

[0123] (6) Subject the mixture III to second roasting, cooling, crushing, and screening to obtain the multi-component material intermediate product NP;

[0124] (7) Mix the multi-component material intermediate product NP, optionally additive N2, and optionally additive N3 to obtain mixture IV;

[0125] (8) Subject the mixture IV to second calcination, cooling, screening, and demagnetization to obtain the multi-component material;

[0126] Step 3: Preparation of the blended lithium-ion battery cathode material

[0127] (9) Uniformly mix the lithium cobaltate material and the multi-component material, followed by screening and demagnetization to obtain the blended lithium-ion battery cathode material;

[0128] Wherein, the first roasting and the second roasting each independently include a first heating stage, a second heating stage, and a heat preservation stage;

[0129] And control the oxygen concentration in the atmosphere of the first heating stage to be less than the oxygen concentration in the atmosphere of the second heating stage; control the heating rate of the first heating stage to be greater than the heating rate of the second heating stage.

[0130] In the present invention, during the preparation of lithium cobalt oxide materials and multi-component materials, a special calcination process is used to calcine a mixture comprising a lithium cobalt oxide precursor, a lithium source, and optionally an additive C1 or a multi-component material precursor, a lithium source, and optionally an additive N1. Specifically, a two-stage temperature increase and one-stage heat preservation steps are adopted, and the two-stage temperature increase processes are respectively carried out in atmospheres with different oxygen concentrations and at different heating rates. Further, the oxygen concentration in the atmosphere of the first heating stage is controlled to be less than the oxygen concentration in the atmosphere of the second heating stage, and the heating rate of the first heating stage is greater than the heating rate of the second heating stage. In this way, a layered transition metal oxide cathode material with a special structure can be prepared, and this cathode material has the characteristics described in the first aspect of the present invention, specifically: when XRD tests are performed on the LCO material and NCM material prepared by the preparation method provided by the present invention, the characteristic peak corresponding to the (104) crystal plane of the cathode material shows a peak splitting phenomenon or trend. In particular, the grain size calculated from the characteristic peak corresponding to the (110) crystal plane of the cathode material is significantly increased, and the tap density and structural stability of the blended lithium-ion battery cathode material containing the LCO material and NCM material are significantly improved. When it is used in a lithium-ion battery, the cycle life and safety of the lithium-ion battery are significantly improved, etc.

[0131] Further, when the blended lithium-ion battery cathode material containing the LCO material and NCM material provided by the present invention is used in a lithium-ion battery, the cycle life, high-temperature storage performance, and safety performance of the lithium-ion battery can be significantly improved. On the one hand, the LCO material and NCM material provided by the present invention themselves have large grain sizes, few grain boundaries, high particle strength, and small specific surface areas, and can maintain the integrity of the particles under a relatively high pressure during the rolling process of the battery electrode sheet. Therefore, the tap density is significantly higher than that of conventional materials. On the other hand, the internal and surface structures of the LCO material and NCM material provided by the present invention are more stable. In particular, the compatibility of the NCM material provided by the present invention with the electrolyte used in the LCO system is relatively high, and it can withstand a higher charging voltage, which can greatly improve the problems of reduced life and increased gas generation when it is used in admixture with the LCO. This significantly improves the tap density, structure, and surface and interface stability of the blended lithium-ion battery cathode material containing the LCO material and NCM material, and further improves the cycle life, high-temperature storage performance, and safety performance of the lithium-ion battery assembled from this blended lithium-ion battery cathode material.

[0132] Furthermore, after the NCM material matrix is coated with an optionally additive N2 and an optionally additive N3 and then further subjected to a second calcination treatment, its compatibility with the electrolyte used in the lithium cobalt oxide system can be greatly improved.

[0133] According to the present invention, the additive C1 and the additive C2 are each independently a compound containing an M' element.

[0134] In the present invention, there is no particular limitation on the specific type of the compound containing the M' element. For example, it can be at least one of oxides, carbonates, fluorides, borides, hydroxides, sulfates, and chlorides, and preferably at least one of oxides, borides, and hydroxides.

[0135] According to the present invention, the additive C3 and the additive N3 are compounds containing the Co element.

[0136] In the present invention, the compound containing the Co element is selected from Co(OH) 2 , CoOOH, Co 3 O 4 , Co m Al 1-m (OH) 3-m , Co m Al 1-m OOH, Co 3-3m Al 3m O 4+m / 2 and CoCl 2 and at least one of them is preferably Co(OH) 2 and / or Co m Al 1-m (OH) 2 , where 0 < m ≤ 0.2.

[0137] According to the present invention, the additive N1 and the additive N2 are each independently a compound containing the M'' element.

[0138] In the present invention, there is no particular limitation on the specific type of the compound containing the M'' element. For example, it can be at least one of oxides, carbonates, fluorides, borides, hydroxides, sulfates, and chlorides, and preferably at least one of oxides, borides, and hydroxides.

[0139] According to the present invention, M' and M'' are each independently selected from at least one of Na, K, B, W, Mo, Rb, V, Ca, Al, Si, Hf, Ta, Y, Sr, Ba, Er, Mg, Ti, Zr, La, Ce, P, F, and Nb.

[0140] Furthermore, M' and M'' are each independently selected from at least one of Na, K, B, Rb, Ca, Mg, Sr, Ba, Zr, La, and Y.

[0141] According to the present invention, in step (1), the amounts of the lithium cobaltate material precursor, the first lithium source, and the additive C1 are such that 0.9 ≤ n(Li) / [n(Co a1 ) + n(Al) + n(M')] ≤ 1.1; 0 ≤ n(M') / [n(Coa1 ) + n(Al) + n(M’)] ≤ 0.05。

[0142] Furthermore, the dosages of the lithium cobaltate material precursor, the first lithium source, and the additive C1 are such that 0.95 ≤ n(Li) / [n(Co a1 ) + n(Al) + n(M’)] ≤ 1.05; 0.001 ≤ n(M’) / [n(Co a1 ) + n(Al) + n(M’)] ≤ 0.02。

[0143] According to the present invention, in step (3), based on [n(Co a1 ) + n(Al) + n(M’)], the cobalt lithium oxide material intermediate product CP, based on n(M’), the additive C2, and based on n(Co a2 )], the dosage of the additive C3 is such that 0 ≤ n(M’) / [n(Co a1 ) + n(Al) + n(Co a2 ) + n(M’)] ≤ 0.05; 0 ≤ n(Co a2 ) / [n(Co a1 ) + n(Al) + n(Co a2 ) + n(M’)] ≤ 0.1。

[0144] Furthermore, based on [n(Co a1 ) + n(Al) + n(M’)], the cobalt lithium oxide material intermediate product CP, based on n(M’), the additive C2, and based on n(Co a2 )], the dosage of the additive C3 is such that 0.001 ≤ n(M’) / [n(Co a1 ) + n(Al) + n(Co a2 ) + n(M’)] ≤ 0.02; 0.02 ≤ n(Co a2 ) / [n(Co a1 ) + n(Al) + n(Co a2 ) + n(M’)] ≤ 0.08。

[0145] According to the present invention, in step (5), the dosages of the multi-component material precursor, the second lithium source, and the additive N1 are such that 0.9 ≤ n(Li) / [n(Ni) + n(Co y ) + n(Mn) + n(M”)] ≤ 1.3, 0 ≤ n(M”) / [n(Ni) + n(Co y ) + n(Mn) + n(M”)] ≤ 0.02。

[0146] Furthermore, the dosages of the multi-component material precursor, the second lithium source, and the additive N1 are such that 1 ≤ n(Li) / [n(Ni) + n(Coy ) + n(Mn) + n(M”)] ≤ 1.2, 0.001 ≤ n(M”) / [n(Ni) + n(Co y ) + n(Mn) + n(M”)] ≤ 0.01.

[0147] According to the present invention, in step (7), taking [n(Ni) + n(Co y ) + n(Mn) + n(M”)] as a reference, for the multi-component material intermediate product NP, taking n(Co β ) as a reference, for the additive N3 and taking n(M”) as a reference, the dosage of the additive N2 is such that 0 ≤ n(Co β ) / [n(Ni) + n(Co y ) + n(Mn) + n(M”)] ≤ 0.10, 0 ≤ n(M”) / [n(Ni) + n(Co y ) + n(Mn) + n(M”)] ≤ 0.02.

[0148] Furthermore, taking [n(Ni) + n(Co y ) + n(Mn) + n(M”)] as a reference, for the multi-component material intermediate product NP, taking n(Co β ) as a reference, for the additive N3 and taking n(M”) as a reference, the dosage of the additive N2 is such that 0.01 ≤ n(Co β ) / [n(Ni) + n(Co y ) + n(Mn) + n(M”)] ≤ 0.08, 0.001 ≤ n(M”) / [n(Ni) + n(Co y ) + n(Mn) + n(M”)] ≤ 0.01.

[0149] According to the present invention, 0.05 ≤ α ≤ 0.9, preferably, 0.05 ≤ α ≤ 0.6, and more preferably 0.1 ≤ α ≤ 0.5.

[0150] In the present invention, there is no particular limitation on the types of the first lithium source and the second lithium source, and they can be conventional lithium sources in the art, such as at least one selected from lithium carbonate, lithium hydroxide, lithium fluoride, lithium chloride, and lithium nitrate. The first lithium source and the second lithium source can be the same or different.

[0151] According to the present invention, the difference in the oxygen concentration in the atmosphere of the second heating stage and the oxygen concentration in the atmosphere of the first heating stage is 10 - 100 vol%, and the difference in the heating rate of the first heating stage and the heating rate of the second heating stage is 5 - 15 °C / min.

[0152] In the present invention, controlling the oxygen concentration in the atmosphere of the first heating stage to be less than that in the atmosphere of the second heating stage and the heating rate of the first heating stage to be greater than that of the second heating stage is more conducive to reducing the number of LCO or NCM crystal nuclei formed, promoting the growth of crystal grains, obtaining larger grain sizes and higher particle strengths, enabling the prepared blended lithium-ion battery cathode material to have a high tap density and structural stability. When used in a lithium-ion battery, it significantly improves the cycle life and safety of the lithium-ion battery, etc.

[0153] According to the present invention, the first calcination is carried out according to the following steps:

[0154] (a) The first heating stage: heating at a first heating rate of ≥5 °C / min to T1 °C in a lean oxygen atmosphere with an oxygen concentration ≤10 vol%;

[0155] (b) The second heating stage: heating at a second heating rate of ≤1 °C / min to T2 °C in an atmosphere with an oxygen concentration ≥20 vol%;

[0156] (c) The heat preservation stage: heat preserving for t1 hours at a temperature of T2 - 10 °C to T2 + 10 °C;

[0157] Wherein, the range of T1 is 600 °C ≤ T1 ≤ 850 °C; T2 is the first calcination temperature, 900 °C ≤ T2 ≤ 1100 °C; t1 is the first calcination time, 4 h ≤ t1 ≤ 15 h.

[0158] In the present invention, T1 refers to the temperature value at which the heating rate changes during the heating process of the first calcination, that is, the turning point temperature between the first heating stage and the second heating stage.

[0159] In the present invention, during the preparation process of the lithium cobalt oxide material, calcining the mixture containing the lithium cobalt oxide material precursor, the first lithium source and optionally the additive C1 by using the above specific process can significantly increase the grain size of the lithium cobalt oxide material, enhance the particle structure stability and particle strength, and improve the powder tap density of the cathode material. Specifically: in the first heating stage, when the O 2 concentration is controlled at a low level, heating is carried out at a relatively fast first heating rate; the purpose is to decompose and melt the lithium source and fully penetrate it into the interior of the precursor particles, and at the same time reduce the rate and time of the reaction between the precursor and the lithium source to generate LCO material crystal nuclei, thereby controlling the number of LCO material crystal nuclei generated. In the second heating stage, heating is carried out at a slower second heating rate, and at the same time the O 2 concentration is increased; the purpose is to accelerate the reaction rate between the precursor and the lithium source, so that the limited number of LCO material crystal nuclei generated in the first heating stage grow rapidly. In the heat preservation stage, O 2The concentration remains at a relatively high level; the purpose is to enable the grains of the LCO material to fully grow and fuse, so that the grain size continues to increase and the material particles become more round and plump.

[0160] Further, the first roasting is carried out according to the following steps:

[0161] (a) The first heating stage: In an oxygen-deficient atmosphere with an oxygen concentration ≤ 5 vol%, heat up to T1 °C at a first heating rate ≥ 6 °C / min;

[0162] (b) The second heating stage: In an atmosphere with an oxygen concentration ≥ 30 vol%, heat up to T2 °C at a second heating rate ≤ 0.8 °C / min;

[0163] (c) The heat preservation stage: Keep warm for t1 hours at a temperature of T2 - 5 °C to T2 + 5 °C;

[0164] Among them, the range of T1 is 650 °C ≤ T1 ≤ 800 °C; T2 is the first roasting temperature, 950 °C ≤ T2 ≤ 1080 °C; t1 is the first roasting time, 6 h ≤ t1 ≤ 12 h.

[0165] According to the present invention, the second roasting is carried out according to the following steps:

[0166] (A) The first heating stage: In an oxygen-deficient atmosphere with an oxygen concentration ≤ 10 vol%, heat up to T3 °C at a first heating rate ≥ 5 °C / min;

[0167] (B) The second heating stage: In an atmosphere with an oxygen concentration ≥ 20 vol%, heat up to T4 °C at a second heating rate ≤ 1 °C / min;

[0168] (C) The heat preservation stage: Keep warm for t2 hours at a temperature of T4 - 10 °C to T4 + 10 °C;

[0169] Among them, the range of T3 is 400 °C ≤ T3 ≤ 800 °C; T4 is the second roasting temperature, 700 °C ≤ T4 ≤ 1000 °C; t2 is the second roasting time, 4 h ≤ t2 ≤ 15 h.

[0170] In the present invention, T3 refers to the temperature value at which the heating rate changes during the heating process of the second roasting, that is, the turning point temperature between the first heating stage and the second heating stage.

[0171] In the present invention, during the preparation of the multi-component material, the above-mentioned specific process is used to calcine the multi-component material precursor, the second lithium source, and optionally the additive N1, so that the prepared multi-component material has a special structure. Specifically, when the NCM material prepared by the preparation method provided by the present invention is subjected to XRD testing, the characteristic peak corresponding to the (104) crystal plane of the NCM material shows a split peak phenomenon or trend. In particular, the grain size and particle strength of the NCM material are significantly increased, the tap density of the blended lithium-ion battery cathode material containing the NCM material is significantly improved, and when it is used in a lithium-ion battery, the cycle life and safety of the lithium-ion battery are significantly improved.

[0172] Further, the second calcination is carried out according to the following steps:

[0173] (A) First heating stage: In an oxygen-deficient atmosphere with an oxygen concentration ≤ 8 vol%, heat up to T3 °C at a first heating rate ≥ 6 °C / min;

[0174] (B) Second heating stage: In an atmosphere with an oxygen concentration ≥ 40 vol%, heat up to T4 °C at a second heating rate ≤ 0.8 °C / min;

[0175] (C) Heat preservation stage: Keep warm for t2 hours at a temperature of T4 - 5 °C to T4 + 5 °C;

[0176] Among them, the range of T3 is 450 °C ≤ T3 ≤ 750 °C; T4 is the second calcination temperature, 750 °C ≤ T4 ≤ 980 °C; t2 is the second calcination time, 6 h ≤ t2 ≤ 12 h.

[0177] According to the present invention, the conditions for the first calcination include: the calcination temperature is 800 - 1000 °C, and the calcination time is 4 - 10 h.

[0178] Further, the conditions for the first calcination include: the calcination temperature is 850 - 950 °C, and the calcination time is 6 - 8 h.

[0179] According to the present invention, the conditions for the second calcination include: the calcination temperature is 700 - 1000 °C, and the calcination time is 4 - 10 h.

[0180] Further, the conditions for the second calcination include: the calcination temperature is 750 - 900 °C, and the calcination time is 6 - 8 h.

[0181] The third aspect of the present invention provides a preparation method for a blended lithium-ion battery cathode material, and the preparation method includes the following steps;

[0182] S1. Mix the lithium cobaltate material precursor, the first lithium source, and optionally the additive C1 to obtain mixture I;

[0183] S2. Subject the mixture I to first roasting, cooling, crushing, and screening to obtain the process product CP of lithium cobaltate material;

[0184] S3. Mix the multi-component material precursor, the second lithium source, and optionally additive N1 to obtain mixture III;

[0185] S4. Subject the mixture III to second roasting, cooling, crushing, and screening to obtain the process product NP of the multi-component material;

[0186] S5. Mix the process product CP of lithium cobaltate material, the process product NP of the multi-component material, optionally additive C2, optionally additive N2, optionally additive C3, and optionally additive N3 to obtain mixture V;

[0187] S6. Subject mixture V to third calcination, cooling, screening, and demagnetization to obtain the blended lithium-ion battery cathode material;

[0188] Wherein, the first roasting and the second roasting each independently include a first heating stage, a second heating stage, and a heat preservation stage;

[0189] And control the oxygen concentration in the atmosphere of the first heating stage to be less than the oxygen concentration in the atmosphere of the second heating stage; control the heating rate of the first heating stage to be greater than the heating rate of the second heating stage.

[0190] In the preparation method of the blended lithium-ion battery cathode material described in the third aspect of the present invention, the types and amounts of other materials involved, the conditions and parameters of each step are the same as those of the preparation method in the aforementioned second aspect. To avoid repetition, certain characteristics of the substances (such as the optional types of substances, etc.) are not repeated in the second aspect of the present invention.

[0191] According to the present invention, in step S5, based on [n(Co a1 ) + n(Al) + n(M’)], the process product CP of lithium cobaltate material, based on [n(Ni) + n(Co y ) + n(Mn) + n(M”)], the process product NP of the multi-component material, based on n(Co a2 ), additive C3, based on n(Co β ), additive N3, based on n(M’), additive C2, and based on n(M”), the amounts of additive N2 are such that:

[0192] [n(Co a1 ) + n(Al) + n(Co a2 ) + n(M’)] : [n(Ni) + n(Co y ) + n(Mn) + n(M”) + n(Coβ )]=(1 - α):α;

[0193] 0 ≤ n(M’) / [n(Co a1 ) + n(Al) + n(Co a2 ) + n(M’)] ≤ 0.05;

[0194] 0 ≤ n(Co a2 ) / [n(Co a1 ) + n(Al) + n(Co a2 ) + n(M’)] ≤ 0.1;

[0195] 0 ≤ n(Co β ) / [n(Ni) + n(Co y ) + n(Mn) + n(M”)] ≤ 0.1;

[0196] 0 ≤ n(M”) / [n(Ni) + n(Co y ) + n(Mn) + n(M”)] ≤ 0.02.

[0197] According to the present invention, in step S6, the conditions for the third calcination include: the calcination temperature is 700 - 950 °C, and the calcination time is 4 - 10 h.

[0198] Furthermore, the conditions for the third calcination include: the calcination temperature is 750 - 900 °C, and the calcination time is 6 - 8 h.

[0199] In the present invention, there is no particular limitation on the lithium cobaltate material precursor, and it can be prepared by a conventional preparation method in the art. For example, the lithium cobaltate material precursor is prepared according to the following steps:

[0200] (I) Prepare a first mixed salt solution by mixing a cobalt salt and an aluminum salt in a molar ratio of n(Co):n(Al) = a1:b; prepare a first precipitating agent solution and a first complexing agent solution from the first precipitating agent and the first complexing agent respectively;

[0201] (II) Simultaneously and separately introduce the first mixed salt solution, the first precipitating agent solution, and the first complexing agent solution into a reaction kettle to carry out a first reaction and a first aging to obtain a first solid - liquid mixture;

[0202] (III) Filter press the first solid - liquid mixture to obtain a filter cake, wash, dry, and perform a low - temperature heat treatment on the filter cake to obtain the lithium cobaltate material precursor.

[0203] In the present invention, there is no particular limitation on the multi - component material precursor, and it can be prepared by a conventional preparation method in the art. For example, the multi - component material precursor is prepared according to the following steps:

[0204] (i) Prepare a second mixed salt solution by mixing nickel salt, cobalt salt, and manganese salt in a molar ratio of n(Ni):n(Co):n(Mn) = x:y:z; separately prepare a second precipitant solution, a second complexing agent solution, and a dispersant solution from the second precipitant, the second complexing agent, and the dispersant, respectively.

[0205] (ii) Simultaneously and separately introduce the second mixed salt solution, the second precipitant solution, the second complexing agent solution, and the dispersant solution into a reaction kettle for a second reaction and a second aging to obtain a second solid-liquid mixture.

[0206] (iii) Filter press the second solid-liquid mixture to obtain a filter cake, and wash and dry the filter cake to obtain a precursor of the multi-component material.

[0207] In the present invention, there is no particular limitation on the type of cobalt salt, and it can be a conventional cobalt salt in the art, such as at least one of cobalt sulfate, cobalt chloride, cobalt nitrate, and cobalt acetate.

[0208] In the present invention, there is no particular limitation on the type of aluminum salt, and it can be a conventional aluminum salt in the art, such as at least one of aluminum sulfate, aluminum chloride, aluminum nitrate, and aluminum phosphate.

[0209] In the present invention, there is no particular limitation on the type of nickel salt, and it can be a conventional nickel salt in the art, such as at least one of nickel sulfate, nickel chloride, nickel nitrate, and nickel acetate.

[0210] In the present invention, there is no particular limitation on the type of manganese salt, and it can be a conventional manganese salt in the art, such as at least one of manganese sulfate, manganese chloride, manganese nitrate, and manganese acetate.

[0211] In the present invention, there is no particular limitation on the types of the first precipitant and the second precipitant, and they can be conventional precipitants in the art, such as at least one selected from ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide, and lithium hydroxide. The first precipitant and the second precipitant can be the same or different.

[0212] In the present invention, there is no particular limitation on the types of the first complexing agent and the second complexing agent, and they can be conventional complexing agents in the art, such as at least one selected from ammonia water, disodium ethylenediaminetetraacetate, ammonium nitrate, ammonium chloride, and ammonium sulfate. The types of the first complexing agent and the second complexing agent can be the same or different.

[0213] In the present invention, there is no particular limitation on the type of the dispersant, and it can be a conventional dispersant in the art, such as at least one selected from polyethylene glycol PEG, polyvinyl alcohol PVA, and polyglycerol.

[0214] According to the present invention, the conditions for the first reaction include: the reaction temperature is 40 - 70 °C, and the pH value control range is 6.5 - 9.5.

[0215] Further, the conditions for the first reaction include: the reaction temperature is 45 - 65 °C, and the pH value control range is 7 - 9.

[0216] According to the present invention, the time for the first aging is 2 - 12 h; preferably 4 - 10 h.

[0217] According to the present invention, the conditions for the second reaction include: the reaction temperature is 40 - 80 °C, and the pH value control range is 7 - 13.

[0218] Further, the conditions for the second reaction include: the reaction temperature is 50 - 70 °C, and the pH value control range is 8 - 12.

[0219] According to the present invention, the time for the second aging is 2 - 8 h; preferably 4 - 10 h.

[0220] According to the present invention, the conditions for the low-temperature heat treatment include: in the presence of air and / or oxygen, treating at a temperature of 500 - 950 °C for 1 - 5 h.

[0221] In the present invention, when preparing the precursor of the lithium cobaltate material, the washed and dried filter cake is subjected to low-temperature heat treatment. In particular, under the above conditions, the low-temperature heat treatment can reduce the volume of the precursor particles of the lithium cobaltate material, increase its density, prevent the volume shrinkage during the roasting stage from being too large, which may cause excessive internal stress in the particles and ultimately lead to particle cracking. It can make the prepared blended lithium-ion battery cathode material have a high tap density and structural stability. When used in a lithium-ion battery, it can significantly improve the cycle life and safety of the lithium-ion battery, etc.

[0222] Further, the conditions for the low-temperature heat treatment include: in the presence of air and / or oxygen, treating at a temperature of 600 - 900 °C for 2 - 4 h.

[0223] The fourth aspect of the present invention provides a blended lithium-ion battery cathode material prepared by the above preparation method.

[0224] The fifth aspect of the present invention provides a lithium-ion battery, and the lithium-ion battery includes the above blended lithium-ion battery cathode material.

[0225] According to the present invention, in a button-type lithium-ion battery using metallic Li as the negative electrode material and the blended lithium-ion battery positive electrode material as the positive electrode material, constant current and constant voltage charging is carried out under the conditions of 3 - 4.5V, 0.1C, 25°C, and a cut-off current of 0.01C. During the first-week charging process of the lithium-ion battery, the charging capacity at voltage ζ1 is Cap1, and the charging capacity at the end of charging is Cap2, where 1 / 3α ≤ λ = Cap1 / Cap2 × 100% ≤ α, and ζ1 is the charging voltage when the lithium cobaltate material is charged to 1% SOC under the same test conditions;

[0226] Based on the total weight of the blended lithium-ion battery positive electrode material, the dosage of the multi-component material is α.

[0227] In the present invention, the lithium-ion battery assembled from the blended lithium-ion battery positive electrode material provided by the present invention has the above characteristics, indicating that the charging voltage of the lithium-ion battery changes greatly in the initial stage, which is conducive to the battery management system (BMS) to accurately identify, manage, and control the battery cells.

[0228] Furthermore, 1 / 2α ≤ λ = Cap1 / Cap2 × 100% ≤ 3 / 4α.

[0229] The present invention will be described in detail below through examples. In the following examples,

[0230] The structure of the positive electrode material is tested by XRD; the instrument used is an X-ray diffractometer (Rigaku, Smart Lab9KW), and the test conditions are: the X-ray source is the Kα ray of Cu, the scanning range is 10° - 80°, the scanning rate is 1° / min, and the scanning step is 0.02°;

[0231] The powder tap density of the positive electrode material is measured by the powder tap method; the instrument used is a powder tap densitometer (MCP-PD51), and the test condition is 20KN.

[0232] The composition of the positive electrode material is measured by ICP method; the instrument used is PE Optima 7000DV, and the test condition is that 0.1g of the sample is completely dissolved in a mixed acid solution of 3mL HNO 3 + 9mL HCl, diluted to 250mL for testing;

[0233] The cycle life and charge-discharge curve of the lithium-ion battery are measured by the button cell method; the instrument used is a Neware battery test cabinet (CT3008), and the test conditions for the first charge-discharge capacity are 0.1C@3 - 4.5V, 25°C, and the constant voltage cut-off current is 0.01C;

[0234] The cycling performance test conditions are 1.0C@3-4.57V, 45°C. During the cycling process, the higher the capacity retention rate, the higher the material stability and the better the cycling performance of the battery system.

[0235] The gas generation (swelling rate) and high-temperature storage performance (capacity retention rate, recovery rate) of lithium-ion batteries are measured using the soft-pack battery method; the instruments used are Neware battery test cabinets (CT3008), vernier calipers, and forced-air constant-temperature ovens. The test methods for the swelling rate, capacity retention rate, and recovery rate are as follows: ① 0.1C@3-4.5V, 25°C, constant current and constant voltage charging + constant current discharging cycle 3 times (the constant voltage cut-off current is 0.01C), record the last discharge capacity as disc1, then charge to the full charge state under the same regime and measure the initial thickness of the battery, denoted as d1; ② Place the battery in step ① in a 60°C constant-temperature oven and keep it warm for 30 days; ③ Take out the battery in step ②, naturally cool it to room temperature, measure the thickness and record it as d2, and discharge it according to the regime in step ①, record the discharge capacity as disc2; ④ Charge and discharge the battery in step ③ according to the regime in step ① for 3 cycles, take the average value of the 3 discharge capacities, denoted as disc3; ⑤ Calculate the swelling rate = (d2 / d1 - 1)*100%, the capacity retention rate = disc2 / disc1*100%, and the capacity recovery rate = disc3 / disc1*100%;

[0236] The raw materials used in the examples and comparative examples are all commercially available products.

[0237] Example 1

[0238] Step 1: Preparation of lithium cobaltate material:

[0239] (1) Prepare a first mixed salt solution with cobalt chloride and aluminum sulfate according to the molar ratio of n(Co):n(Al) = a1:b; prepare a first precipitant solution and a first complexing agent solution with ammonium bicarbonate and disodium ethylenediaminetetraacetate respectively;

[0240] (2) Simultaneously and separately introduce the first mixed salt solution, the first precipitant solution, and the first complexing agent solution into the reaction kettle for the first reaction and the first aging to obtain a first solid-liquid mixture;

[0241] (3) Filter the first solid-liquid mixture to obtain a filter cake, wash, dry, and perform low-temperature heat treatment on the filter cake to obtain a lithium cobaltate cathode material precursor;

[0242] (4) Mix the lithium cobaltate material precursor, lithium carbonate, and additive C1 (BaSO 4 ) to obtain mixture I;

[0243] (5) Perform the first roasting, cooling, crushing, and screening on mixture I to obtain the lithium cobaltate cathode material intermediate product CP;

[0244] (6) Mix the lithium cobalt oxide material process product CP, additive C2 (Y 2 O 3 ), and additive C3 (Co(OH) 2 ) to obtain mixture II;

[0245] (7) Subject mixture II to first calcination, cooling, screening, and demagnetization to obtain the lithium cobalt oxide material (LCO-A1);

[0246] Step 2: Preparation of the multi-component material

[0247] (8) Prepare a second mixed salt solution with nickel sulfate, cobalt sulfate, and manganese sulfate in a molar ratio of n(Ni):n(Co):n(Mn) = x:y:z; separately prepare a second precipitant solution, a second complexing agent solution, and a dispersant solution with sodium hydroxide, ammonia water, and polyethylene glycol PEG, respectively;

[0248] (9) Simultaneously and separately introduce the second mixed salt solution, the second precipitant solution, the second complexing agent solution, and the dispersant solution into the reaction kettle for second reaction and second aging to obtain a second solid-liquid mixture;

[0249] (10) Filter press the second solid-liquid mixture to obtain a filter cake, and wash and dry the filter cake to obtain a multi-component material precursor;

[0250] (11) Mix the multi-component material precursor, lithium hydroxide, and additive N1 (ZrO 2 ) to obtain mixture III;

[0251] (12) Subject mixture III to second roasting, cooling, crushing, and screening to obtain a multi-component material process product NP;

[0252] (13) Mix the multi-component material process product NP, additive N2 (Y 2 O 3 ), and additive N3 (Co 0.95 Al 0.05 (OH) 2.05 ) to obtain mixture IV;

[0253] (14) Subject mixture IV to second calcination, cooling, screening, and demagnetization to obtain the multi-component material (NCM-A1);

[0254] Step 3: Preparation of the blended lithium-ion battery cathode material

[0255] (15) Uniformly mix, screen, and demagnetize the lithium cobalt oxide material (LCO-A1) and the multi-component material (NCM-A1) to obtain the blended lithium-ion battery cathode material S1. Among them, based on the total weight of the blended lithium-ion battery cathode material, the dosage of the multi-component material is α; among them, each of the first roasting and the second roasting independently includes a first heating stage, a second heating stage, and a heat preservation stage;

[0256] And control the oxygen concentration in the atmosphere of the first heating stage to be less than the oxygen concentration in the atmosphere of the second heating stage; control the heating rate of the first heating stage to be greater than the heating rate of the second heating stage.

[0257] The dosages of the various materials and the specific operating conditions in the preparation process are shown in Tables 1 and 2.

[0258] In the blended lithium-ion battery cathode material S1, the compositions and ratios of the LCO material and the NCM material are shown in Table 3.

[0259] Examples 2-24 and Comparative Examples 1-7 were prepared for the blended lithium-ion battery cathode material according to the method of Example 1, except that: the dosages of the various materials and the specific operating conditions were different, and the details are shown in Tables 1 and 2. The compositions and ratios of the LCO material and the NCM material are shown in Table 3.

[0260] Table 1

[0261]

[0262]

[0263] Table 1 (continued)

[0264]

[0265]

[0266] Table 1 (continued)

[0267]

[0268]

[0269] Table 1 (continued)

[0270]

[0271]

[0272] Table 1 (continued)

[0273]

[0274]

[0275] Table 2

[0276]

[0277]

[0278] Table 2 (continued)

[0279]

[0280]

[0281] Table 2 (continued)

[0282]

[0283]

[0284] Table 2 (continued)

[0285]

[0286]

[0287] Table 2 (continued)

[0288]

[0289]

[0290] Table 3

[0291] Project LCO composition NCM composition α S1 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S2 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.35 S3 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.4 S4 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.5 S5 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.1 S6 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.05 S7 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.6 S8 <![CDATA[Li 1.05 Co 0.977 Al 0.002 B 0.02 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S9 <![CDATA[Li 0.98 Co 0.899 Al 0.1 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S10 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S11 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S12 <![CDATA[Li 0.99 Co 0.978 Al 0.02 Ba 0.001 Zr 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S13 <![CDATA[Li 1.015 Co 0.969 Al 0.02 Ba 0.001 Mg 0.01 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S14 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.07 Ni 0.33 Co 0.33 Mn 0.329 Na 0.01 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S15 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[LiNi 0.8 Co 0.1 Mn 0.098 Sr 0.001 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S16 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S17 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S18 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.045 Ni 0.6 Co 0.1 Mn 0.296 Zr 0.002 W 0.002 O2·0.005LiCo 0.9 Al 0.1 O 2 > 0.3 S19 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 0.97 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 La 0.001 O 2 ·0.08LiCo 0.99 Al 0.01 O 2 > 0.3 S20 <![CDATA[Li 1.01 Co 0.98 Al 0.02 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.3 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S21 <![CDATA[Li 1.01 Co 0.98 Al 0.02 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.3 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S22 <![CDATA[Li 1.01 Co 0.98 Al 0.02 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.3 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S23 <![CDATA[Li 1.03 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 S24 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.05 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 > 0.3 D1 <![CDATA[Li 1.01 Co 0.98 Al 0.02 O 2 > / 0 D2 / <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.3 O 2 > 1 D3 <![CDATA[Li 1.01 Co 0.98 Al 0.02 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.3 O 2 > 0.3 D4 <![CDATA[Li 1.01 Co 0.98 Al 0.02 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.3 O 2 > 0.7 D5 <![CDATA[Li 1.01 Co 0.978 Al 0.02 Ba 0.001 Y 0.001 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.297 Zr 0.002 Y 0.001 O 2 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3 D6 <![CDATA[Li 1.01 Co 0.98 Al 0.02 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.3 O 2 > 0.3 D7 <![CDATA[Li 1.01 Co 0.98 Al 0.02 O 2 > <![CDATA[Li 1.02 Ni 0.6 Co 0.1 Mn 0.3 ·0.03LiCo 0.95 Al 0.05 O 2 > 0.3

[0292] Test example

[0293] The positive electrode materials prepared in the examples and comparative examples were subjected to XRD tests, the characteristic peaks (104) of the XRD patterns were deconvoluted, and the grain sizes of the LCO and NCM materials were calculated based on the characteristic peaks (110). The results are shown in Table 4.

[0294] The tap densities of the positive electrode materials prepared in the examples and comparative examples were tested. The results are shown in Table 4.

[0295] Table 4

[0296]

[0297] Table 4 (continued)

[0298] Result <![CDATA[A N(104) / B N(104) > <![CDATA[A C(104) / B C(104) > <![CDATA[I AN / I BN > <![CDATA[I AC / I BC > <![CDATA[PD / g / cm 3 > S1 2.74 2.53 2.21 2.06 4.31 S2 2.80 2.67 2.20 2.15 4.22 S3 2.94 2.31 2.24 2.09 4.17 S4 3.06 2.83 2.30 2.03 4.08 S5 2.35 3.35 2.10 2.20 4.29 S6 2.28 3.41 2.04 2.18 4.18 S7 3.10 2.27 2.36 1.99 3.97 S8 2.58 2.25 2.18 2.10 4.25 S9 3.14 3.16 2.27 2.23 4.15 S10 2.82 2.61 2.21 2.09 4.26 S11 2.63 2.36 2.22 2.18 4.21 S12 2.71 2.58 2.24 2.10 4.18 S13 2.67 2.42 2.17 2.12 4.24 S14 2.68 2.47 2.32 2.16 4.27 S15 2.73 2.76 2.17 2.08 4.05 S16 2.66 2.63 2.26 2.13 4.15 S17 2.79 2.85 2.25 2.11 4.18 S18 2.57 2.66 2.28 2.04 4.12 S19 2.84 2.59 2.15 2.06 4.22 S20 2.71 2.47 2.24 2.10 4.29 S21 2.68 2.27 2.36 2.01 3.88 S22 3.01 2.61 2.03 2.08 4.02 S23 2.66 2.51 2.19 2.13 4.18 S24 2.71 2.46 2.22 2.04 4.13 D1 ※ ※ ※ ※ 3.89 D2 ※ ※ ※ ※ 3.15 D3 ※ ※ ※ ※ 3.67 D4 ※ ※ ※ ※ 3.37 D5 ※ ※ ※ ※ 3.59 D6 ※ 2.58 ※ 2.15 3.76 D7 2.73 ※ 2.27 ※ 3.44

[0299] Note: ※ indicates that there is no peak splitting phenomenon or trend in the (104) peak of the XRD pattern of the cathode material, so there are some missing values in the XRD peak splitting results.

[0300] As can be seen from Table 4, compared with Comparative Examples 1-7, in the blended lithium-ion battery cathode materials provided in Examples 1-24 of the present invention, the characteristic peak C(104) corresponding to the (104) crystal plane of the lithium cobaltate material shows a peak splitting phenomenon, and after peak splitting, it shows a double-peak distribution. Moreover, the characteristic peak N(104) corresponding to the (104) crystal plane of the multi-component material shows a peak splitting trend, and after peak splitting, it shows a double-peak distribution.

[0301] Among them, in the blended lithium-ion battery cathode material provided in Comparative Example 6, although the characteristic peak C(104) corresponding to the (104) crystal plane of the lithium cobaltate material shows a peak splitting phenomenon and shows a double-peak distribution after peak splitting, the characteristic peak N(104) corresponding to the (104) crystal plane of the multi-component material does not show a peak splitting phenomenon or trend, and does not show a double-peak distribution after peak splitting. In the blended lithium-ion battery cathode material provided in Comparative Example 7, although the characteristic peak N(104) corresponding to the (104) crystal plane of the multi-component material shows a peak splitting trend and shows a double-peak distribution after peak splitting, the characteristic peak C(104) corresponding to the (104) crystal plane of the lithium cobaltate material does not show a peak splitting phenomenon or trend, and does not show a double-peak distribution after peak splitting.

[0302] Furthermore, by using the specific first sintering and second sintering conditions of the present invention, it can significantly make the prepared LCO material and NCM material have significantly larger SizeC and SizeN.

[0303] Furthermore, as the blending ratio α of the multi-component material in the blended lithium-ion battery cathode material changes, the A N(104) / A C(104) 、B N(104) / B C(104) 、I BN / I BC 、I AN / I AC of the prepared blended lithium-ion battery cathode material also changes accordingly and shows an obvious correlation.

[0304] Compared with Comparative Examples 1-7, the tap density PD of the blended lithium-ion battery cathode materials provided in Examples 1-24 of the present invention is significantly improved.

[0305] Furthermore, there is an obvious correlation between the tap density PD of the blended lithium-ion battery cathode material provided in the examples and the blending ratio α of the multi-component material NCM in the blended lithium-ion battery cathode material. In particular, when the blending ratio α is 0.3, the prepared blended lithium-ion battery cathode material has the highest tap density PD.

[0306] Figure 1 is the XRD pattern of the blended lithium-ion battery cathode material S1 prepared in Example 1, Figure 2 is a schematic diagram after peak separation processing of the XRD pattern of the blended lithium-ion battery cathode material S1 prepared in Example 1; from Figure 1 and Figure 2 it can be seen that the blended lithium-ion battery cathode material has two (104) characteristic peaks, namely N(104) and C(104), which are the characteristic peaks corresponding to the (104) crystal planes of the NCM material and the LCO material respectively; both the N(104) and C(104) peaks show a peak separation phenomenon or trend, that is, the N(104) and C(104) characteristic peaks both show an obviously asymmetric structure on the left and right. In the shown XRD pattern, by performing peak separation on the XRD pattern of the blended lithium-ion battery cathode material, the N(104) and C(104) characteristic peaks are respectively divided into two peaks, both of which can be divided into the first peak (A, left) and the second peak (B, right).

[0307] Figure 3 、 Figure 4 and Figure 5 are the XRD patterns of the blended lithium-ion battery cathode materials prepared in Example 2, Example 3 and Comparative Example 3 respectively. From Figure 1 、 Figure 3 and Figure 4 it can be seen that the blended lithium-ion battery cathode materials prepared by the method of the present invention all have two (104) characteristic peaks, and both of the two (104) characteristic peaks show a peak separation phenomenon or trend, that is, the N(104) and C(104) characteristic peaks both show an obviously asymmetric structure on the left and right, and the same method as in Example 1 can be used for peak separation processing; at the same time, as the blending ratio of the multi-component material increases, that is, as the α value increases, the peak intensity of the N(104) peak gradually increases, and the peak intensity of the C(104) peak gradually decreases, and the peak intensity of the N(104) peak gradually exceeds the peak intensity of the C(104) peak. From Figure 5 it can be seen that the blended lithium-ion battery cathode material prepared in Comparative Example 3 also has two (104) characteristic peaks, but no peak separation phenomenon or trend appears in these two (104) characteristic peaks, that is, the N(104) and C(104) characteristic peaks both show a basically symmetric structure on the left and right. When using the same method as in Example 1 for peak separation processing, it is impossible to separate into two sub-peaks.

[0308] Application Example

[0309] The cathode materials prepared in the examples and comparative examples were used to assemble lithium-ion batteries, and the specific assembly process is as follows:

[0310] The coin cell was prepared according to the following steps:

[0311] Mix 9.2 g of the cathode material, 0.4 g of acetylene black, and 0.4 g of polyvinylidene fluoride (PVDF), coat it on an aluminum foil and perform a drying treatment, press and form it under a pressure of 100 MPa to obtain a cathode electrode sheet with a diameter of 12 mm and a thickness of 120 μm. Then, place this cathode electrode sheet in a vacuum drying oven and dry it at 120 °C for 12 h.

[0312] For the anode, use a Li metal sheet with a diameter of 17 mm and a thickness of 1 mm; for the separator, use a polyethylene porous membrane with a thickness of 25 μm; for the electrolyte, use an equal - volume mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) with 1 mol / L of LiPF 6 as the electrolyte.

[0313] Assemble the cathode electrode sheet, separator, anode electrode sheet, and electrolyte into a 2025 - type coin cell in an Ar - gas glove box with a water content and an oxygen content both less than 5 ppm.

[0314] The soft - pack battery is prepared according to the following steps:

[0315] Mix 920 g of the cathode material, 40 g of acetylene black, and 40 g of polyvinylidene fluoride (PVDF), add NMP to make a slurry, coat it on an aluminum foil and perform drying, rolling, and cutting treatments to obtain a cathode electrode sheet with a length of 400 mm and a width of 50 mm. Then, place this cathode electrode sheet in a vacuum drying oven and dry it at 120 °C for 12 h.

[0316] For the anode, use natural graphite material coated on a copper foil, and fabricate an anode electrode sheet with a length of 402 mm and a width of 50 mm in a method similar to that of the cathode; for the separator, use a polyethylene porous membrane with a thickness of 25 μm and a width of 52 mm; for the electrolyte, use an equal - volume mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) with 1 mol / L of LiPF 6 as the electrolyte.

[0317] Assemble the cathode electrode sheet, separator, anode electrode sheet, aluminum - plastic shell, and electrolyte into a 52 * 30 mm small - sized soft - pack battery in an Ar - gas glove box with a water content and an oxygen content both less than 5 ppm.

[0318] Test the cycling performance and charge - discharge capacity of the assembled lithium - ion battery, and the results are shown in Table 5.

[0319] Table 5

[0320]

[0321]

[0322] As can be seen from the results in Table 5, compared with Comparative Examples 1-7, the lithium-ion batteries assembled with the blended lithium-ion battery cathode materials provided by Examples 1-24 of the present invention have higher cycle life, lower swelling rate, higher capacity retention rate and higher capacity recovery rate.

[0323] Furthermore, in Examples 21 and 22, since the heating rate or oxygen concentration during the first roasting and the second roasting did not fall within the preferred range of the present invention, compared with Examples 1-20, the cycle life, swelling rate, capacity retention rate, capacity recovery rate, etc. of the lithium-ion batteries assembled with the blended lithium-ion battery cathode materials prepared in Examples 21 and 22 deteriorated.

[0324] Furthermore, in Comparative Examples 6 and 7, the first sintering process and the second sintering process of the present invention were separately used to prepare the blended lithium-ion battery cathode materials. It can be seen from Table 5 that compared with Comparative Examples 3-5, when the cathode materials of Comparative Examples 6 and 7 using the first sintering process or the second sintering process of the present invention alone were used to assemble lithium-ion batteries, although the cycle life, swelling rate, capacity retention rate and capacity recovery rate were improved to a certain extent, they were still significantly inferior to Examples 1-24.

[0325] It can be seen from Table 5 that for the lithium-ion battery, under the conditions of constant current and constant voltage charging at 3-4.5V (vs. Li + / Li), 0.1C, 25°C and a cut-off current of 0.01C, during the first week charging process of the lithium-ion battery, the charging capacity at voltage ζ1 is Cap1, and the charging capacity at the end of charging is Cap2. There is a correlation between the ratio λ value of Cap1 to Cap2 and the blending ratio α. Specifically, λ increases with the increase of α. Furthermore, λ and α show an obvious linear relationship, that is, the value of λ / α is relatively stable, with a small fluctuation range, and the value range is: 1 / 2 ≤ λ / α ≤ 3 / 4.

[0326] Figure 6 are the charge-discharge curves of the lithium-ion batteries assembled with the cathode materials of Example 1 and Comparative Example 1. From Figure 6 it can be seen that the charging voltage of Example 1 below 20% SOC is lower than that of Comparative Example 1, and as the charging process progresses, the voltage rises rapidly; the discharging voltage of Example 1 below 20% SOC is also significantly lower than that of Comparative Example 1, and as the discharging process progresses, the voltage decreases faster than that of Comparative Example 1. That is, whether it is the initial charging stage or the later discharging stage, the voltage change range of the battery corresponding to Example 1 is larger, which is more convenient for the battery management system (BMS) to accurately measure and determine the state of charge of the battery cell, so as to more accurately perform targeted charging, discharging, standing, isolation and other related operations on battery cells in different states.

[0327] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A blended lithium-ion battery cathode material, characterized in that, the cathode material comprises lithium cobaltate material and a multi-component material; by XRD test, the characteristic peaks (104) of the lithium cobaltate material and the multi-component material in the blended lithium-ion battery cathode material satisfy the following characteristics: (1) The characteristic peak C(104) corresponding to the (104) crystal plane of the lithium cobaltate material shows a double-peak distribution after peak separation; the characteristic peak N(104) corresponding to the (104) crystal plane of the multi-component material shows a double-peak distribution after peak separation; based on the total weight of the blended lithium-ion battery cathode material, the weight ratio of the multi-component material is α; 0.05 ≤ α ≤ 0.9; by XRD test, the grain size Size C of the (110) crystal plane of the lithium cobaltate material satisfies: 800 Å ≤ Size C ≤ 2000 Å; the grain size Size N of the (110) crystal plane of the multi-component material satisfies: 500 Å ≤ Size N ≤ 1500 Å.

2. The blended lithium-ion battery cathode material according to claim 1, wherein, by XRD test, the characteristic peak (104) of the blended lithium-ion battery cathode material satisfies the following characteristics: (2)7α 2 ≤A N(104) / A C(104) ≤13α 2 ,A N(104) is the peak area of the first peak after peak deconvolution of N(104), and A C(104) is the peak area of the first peak after peak deconvolution of C(104); (3)6α 2 ≤I AN / I AC ≤12α 2 ,I AN is the peak intensity of the first peak after peak separation of N(104), and I AC is the peak intensity of the first peak after peak separation of C(104).

3. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, based on the total weight of the blended lithium-ion battery cathode material, the weight ratio of the multi-component material is α; by XRD test, the characteristic peak (104) of the blended lithium-ion battery cathode material satisfies the following characteristics: (2)8α 2 ≤A N(104) / A C(104) ≤12α 2 ,A N(104) is the peak area of the first peak after peak deconvolution of N(104), and A C(104) is the peak area of the first peak after peak deconvolution of C(104); (3)7α 2 ≤I AN / I AC ≤11α 2 ,I AN is the peak intensity of the first peak after peak separation of N(104), and I AC is the peak intensity of the first peak after peak separation of C(104).

4. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, based on the total weight of the blended lithium-ion battery cathode material, the weight ratio of the multi-component material is α; 0.05 ≤ α ≤ 0.

6.

5. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, based on the total weight of the blended lithium-ion battery cathode material, the weight ratio of the multi-component material is α; 0.1 ≤ α ≤ 0.

5.

6. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, based on the total weight of the blended lithium-ion battery cathode material, the weight ratio of the multi-component material is α; by XRD test, the characteristic peak (104) of the blended lithium-ion battery cathode material satisfies the following characteristics: (4)6α 2 ≤B N(104) / B C(104) ≤12α 2 ,B N(104) is the peak area of the second peak after peak separation of N(104), and B C104) is the peak area of the second peak after peak separation of C(104); (5)5α 2 ≤I BN / I BC ≤11α 2 ,I BN is the peak intensity of the second peak after peak separation of N(104), and I BC is the peak intensity of the second peak after peak separation of C(104).

7. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, based on the total weight of the blended lithium-ion battery cathode material, the weight ratio of the multi-component material is α; by XRD test, the characteristic peak (104) of the blended lithium-ion battery cathode material satisfies the following characteristics: (4)7α 2 ≤B N(104) / B C(104) ≤11α 2 ,B N(104) is the peak area of the second peak after peak deconvolution of N(104), and B C104) is the peak area of the second peak after peak deconvolution of C(104); (5)6α 2 ≤I BN / I BC ≤10α 2 ,I BN is the peak intensity of the second peak after peak separation of N(104), and I BC is the peak intensity of the second peak after peak separation of C(104).

8. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, The powder tap density of the blended lithium-ion battery cathode material ≥ 3.8 g / cm 3 .

9. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, The tap density of the blended lithium-ion battery cathode material ≥ 4 g / cm 3 .

10. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, by XRD test, the characteristic peak (104) of the lithium cobaltate material satisfies the following characteristics: (i-C) 1.8 ≤ I AC / I BC ≤ 2.4, I AC is the peak intensity of the first peak after peak deconvolution of C(104), I BC is the peak intensity of the second peak after peak deconvolution of C(104); (ii-C)2 ≤ A C(104) / B C(104) ≤ 4, A C(104) is the peak area of the first peak after peak deconvolution of C(104), B C(104) is the peak area of the second peak after peak deconvolution of C(104).

11. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, After XRD testing, the characteristic peak (104) of the lithium cobaltate material satisfies the following characteristics: (i-C) 1.9 ≤ I AC / I BC ≤ 2.3, I AC is the peak intensity of the first peak after peak separation of C(104), I BC is the peak intensity of the second peak after peak separation of C(104); (ii-C) 2.2 ≤ A C(104) / B C(104) ≤ 3.5, A C(104) is the peak area of the first peak after peak deconvolution of C(104), B C(104) is the peak area of the second peak after peak deconvolution of C(104).

12. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, After XRD testing, the grain size Size C of the (110) crystal plane of the lithium cobaltate material satisfies: 900 Å ≤ Size C ≤ 1800 Å.

13. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, After XRD testing, the characteristic peak (104) of the multi-component material satisfies the following characteristics: (i-N)1.9 ≤ I AN / I BN ≤ 2.5, I AN is the peak intensity of the first peak after peak separation of N(104), I BN is the peak intensity of the second peak after peak separation of N(104); (ii-N)2 ≤ A N(104) / B N(104) ≤ 4, A N(104) is the peak area of the first peak after peak deconvolution of N(104), B N(104) is the peak area of the second peak after peak deconvolution of N(104).

14. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, After XRD testing, the characteristic peak (104) of the multi-component material satisfies the following characteristics: (i-N)2 ≤ I AN / I BN ≤ 2.4, I AN is the peak intensity of the first peak after peak separation of N(104), I BN is the peak intensity of the second peak after peak separation of N(104); (ii-N) 2.5 ≤ A N(104) / B N(104) ≤ 3.5, A N(104) is the peak area of the first peak after peak separation of N(104), B N(104) is the peak area of the second peak after peak separation of N(104).

15. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, After XRD testing, the grain size Size N of the (110) crystal plane of the multi-component material satisfies: 600 Å ≤ Size N ≤ 1200 Å.

16. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, The lithium cobaltate material has the composition shown in Formula I: Li n1 Co a Al b M’ 1-a-b O 2 Formula I where, 0.9 ≤ n1 ≤ 1.1, 0.8 ≤ a1 <0.99, 0 < b ≤ 0.1, 0 ≤ a2 ≤ 0.1, 0 ≤ 1 - a - b ≤ 0.05, a = a1+ a2 ; M’ is selected from at least one of Na, K, B, W, Mo, Rb, V, Ca, Al, Si, Hf, Ta, Y, Sr, Ba, Er, Mg, Ti, Zr, La, Ce, P, F and Nb; The multi-component material has the composition shown in Formula II: Li n2 Ni x Co y Mn z M’’ 1-x-y-z O 2 ·βLiCo c Al 1-c O 2 Formula II; Among them, Li n2 Ni x Co y Mn z M’’ 1-x-y-z O 2 is a multi-component material matrix, LiCo c Al 1-c O 2 is a coating layer, 0 ≤ β ≤ 0.1; Among them, 0.9 ≤ n2 ≤ 1.3, 0 < x <1, 0 ≤ y ≤ 0.5, 0 ≤ z ≤ 0.5, 0 ≤ 1 - x - y - z ≤ 0.02, 0.8 ≤ c ≤ 1; M’’ is selected from at least one of Na, K, B, W, Mo, Rb, V, Ca, Al, Si, Hf, Ta, Y, Sr, Ba, Er, Mg, Ti, Zr, La, Ce, P and Nb.

17. The blended lithium-ion battery cathode material according to claim 1 or 2, wherein, The lithium cobaltate material has the composition shown in Formula I: Li n1 Co a Al b M’ 1-a-b O 2 Formula I wherein, 0.95 ≤ n1 ≤ 1.05, 0.85 ≤ a1 <0.98, 0.001 ≤ b ≤ 0.08, 0.02 ≤ a2 ≤ 0.08, 0.001 ≤ 1 - a - b ≤ 0.02, a = a1 + a2 ; M’ is selected from at least one of Na, K, B, Rb, Ca, Al, Mg, Sr, Ba, Zr, La, F and Y; The multi-component material has the composition shown in Formula II: Li n2 Ni x Co y Mn z M’’ 1-x-y-z O 2 ·βLiCo c Al 1-c O 2 Formula II; Among them, Li n2 Ni x Co y Mn z M’’ 1-x-y-z O 2 is the multi-element material matrix, LiCo c Al 1-c O 2 is the coating layer, 0.01 ≤ β ≤ 0.08; Among them, 1.0 ≤ n2 ≤ 1.2, 0.3 < x <1, 0 ≤ y ≤ 0.3, 0 < z ≤ 0.4, 0.001 ≤ 1 - x - y - z ≤ 0.01, 0.9 ≤ c ≤ 0.99; M’’ is selected from at least one of Na, K, B, Rb, Ca, Mg, Sr, Ba, Zr, La and Y.

18. A method for preparing the blended lithium-ion battery cathode material according to claim 16 or 17, characterized in that, The preparation method includes the following steps: Step 1: Preparation of the lithium cobaltate material (1) Mix the lithium cobaltate material precursor, the first lithium source and optionally additive C1 to obtain mixture I; (2) Perform the first calcination, cooling, crushing and screening on the mixture I to obtain the lithium cobaltate material intermediate product CP; (3) Mix the lithium cobaltate material intermediate product CP, optionally additive C2 and optionally additive C3 to obtain mixture II; (4) Perform the first calcination, cooling, screening and demagnetization on mixture II to obtain the lithium cobaltate material; Step 2: Preparation of the multi-component material (5) Mix the multi-component material precursor, the second lithium source and optionally additive N1 to obtain mixture III; (6) Subject the mixture III to a second calcination, cooling, crushing, and screening to obtain a poly-material intermediate product NP; (7) Mix the poly-material intermediate product NP, optionally additive N2, and optionally additive N3 to obtain a mixture IV; (8) Subject the mixture IV to a second calcination, cooling, screening, and demagnetization to obtain the poly-material; Step 3: Preparation of the blended lithium-ion battery cathode material (9) Uniformly mix, screen, and demagnetize the lithium cobaltate material and the poly-material to obtain the blended lithium-ion battery cathode material; Wherein, each of the first calcination and the second calcination independently includes a first heating stage, a second heating stage, and a heat preservation stage; And control the oxygen concentration in the atmosphere of the first heating stage to be less than the oxygen concentration in the atmosphere of the second heating stage; control the heating rate of the first heating stage to be greater than the heating rate of the second heating stage; Each of the additive C1 and the additive C2 is independently a compound containing M' element; The additive C3 and the additive N3 are compounds containing Co element; Each of the additive N1 and the additive N2 is independently a compound containing M'' element.

19. A method for preparing the blended lithium-ion battery cathode material according to claim 16 or 17, characterized in that, the preparation method includes the following steps: S1. Mix a lithium cobaltate material precursor, a first lithium source, and optionally additive C1 to obtain a mixture I; S2. Subject the mixture I to a first calcination, cooling, crushing, and screening to obtain a lithium cobaltate material intermediate product CP; S3. Mix a poly-material precursor, a second lithium source, and optionally additive N1 to obtain a mixture III; S4. Subject the mixture III to a second calcination, cooling, crushing, and screening to obtain a poly-material intermediate product NP; S5. Mix the lithium cobaltate material intermediate product CP, the poly-material intermediate product NP, optionally additive C2, optionally additive N2, optionally additive C3, and optionally additive N3 to obtain a mixture V; S6. Subject the mixture V to a third calcination, cooling, screening, and demagnetization to obtain the blended lithium-ion battery cathode material; Wherein, each of the first calcination and the second calcination independently includes a first heating stage, a second heating stage, and a heat preservation stage; And control the oxygen concentration in the atmosphere of the first heating stage to be less than the oxygen concentration in the atmosphere of the second heating stage; control the heating rate of the first heating stage to be greater than the heating rate of the second heating stage; Each of the additive C1 and the additive C2 is independently a compound containing M' element; The additive C3 and the additive N3 are compounds containing Co element; Each of the additive N1 and the additive N2 is independently a compound containing M'' element.

20. According to the preparation method of claim 18 or 19, wherein, M’ and M’’ are each independently selected from at least one of Na, K, B, W, Mo, Rb, V, Ca, Al, Si, Hf, Ta, Y, Sr, Ba, Er, Mg, Ti, Zr, La, Ce, P, F and Nb.

21. The preparation method according to claim 18 or 19, wherein, In step (1) or step S1, the amounts of the lithium cobaltate material precursor, the first lithium source, and the additive C1 are such that 0.9 ≤ n(Li) / [n(Co a1 ) + n(Al) + n(M’)] ≤ 1.1; 0 ≤ n(M’) / [n(Co a1 ) + n(Al) + n(M’)] ≤ 0.

05.

22. The preparation method according to claim 18, wherein, In step (3), based on [n(Co a1 ) + n(Al) + n(M’)], for the lithium cobaltate material process product CP, based on n(M’), for the additive C2, and based on n(Co a2 ), the dosage of the additive C3 is such that 0 ≤ n(M’) / [n(Co a1 ) + n(Al) + n(Co a2 ) + n(M’)] ≤ 0.05; 0 ≤ n(Co a2 ) / [n(Co a1 ) + n(Al) + n(Co a2 ) + n(M’)] ≤ 0.1 23. The preparation method according to claim 18 or 19, wherein, In step (5) or step S3, the amounts of the multi-component material precursor, the second lithium source, and the additive N1 are such that 0.9 ≤ n(Li) / [n(Ni) + n(Co y ) + n(Mn) + n(M'')] ≤ 1.3 and 0 ≤ n(M'') / [n(Ni) + n(Co y ) + n(Mn) + n(M'')] ≤ 0.

02.

24. The preparation method according to claim 18, wherein, In step (7), based on [n(Ni) + n(Co y ) + n(Mn) + n(M'')], for the multi-component material intermediate product NP, based on n(Co β ), for the additive N3, and based on n(M''), for the additive N2, the dosages are such that 0 ≤ n(Co β ) / [n(Ni) + n(Co y ) + n(Mn) + n(M'')] ≤ 0.10; 0 ≤ n(M'') / [n(Ni) + n(Co y ) + n(Mn) + n(M'')] ≤ 0.02。 25. The preparation method according to claim 19, wherein, In step S5, in terms of [n(Co a1 ) + n(Al) + n(M’)], for the lithium cobaltate material process product CP, in terms of [n(Ni) + n(Co y ) + n(Mn) + n(M’’)], for the multi-component material process product NP, in terms of n(Co a2 ), for the additive C3, in terms of n(Co β ), for the additive N3, in terms of n(M’), for the additive C2 and in terms of n(M’’), the dosages of the additive N2 are such that: [n(Co a1 ) + n(Al) + n(Co a2 ) + n(M’)] : [n(Ni) + n(Co y ) + n(Mn) + n(M’’) + n(Co β )] = (1 - α) : α; 0 ≤ n(M’) / [n(Co a1 ) + n(Al) + n(Co a2 ) + n(M’)] ≤ 0.05; 0 ≤ n(Co a2 ) / [n(Co a1 ) + n(Al) + n(Co a2 ) + n(M’)] ≤ 0.1; 0 ≤ n(Co β ) / [n(Ni) + n(Co y ) + n(Mn) + n(M'')] ≤ 0.1; 0 ≤ n(M'') / [n(Ni) + n(Co y ) + n(Mn) + n(M'')] ≤ 0.02。 26. The preparation method according to claim 18, wherein, In step (9), based on the total weight of the blended lithium-ion battery cathode material, the weight ratio of the multi-component material is α; 0.05 ≤ α ≤ 0.

9.

27. The preparation method according to claim 18, wherein, In step (9), based on the total weight of the blended lithium-ion battery cathode material, the weight ratio of the multi-component material is α; 0.05 ≤ α ≤ 0.

6.

28. The preparation method according to claim 18, wherein, In step (9), based on the total weight of the blended lithium-ion battery cathode material, the weight ratio of the multi-component material is α; 0.1≤α≤0.5。 29. The preparation method according to claim 18 or 19, wherein, The difference in the oxygen concentration in the atmosphere in the second heating stage and the oxygen concentration in the atmosphere in the first heating stage is 10 - 100 vol%; the difference in the heating rate in the first heating stage and the heating rate in the second heating stage is 5 - 15 °C / min.

30. The preparation method according to claim 18 or 19, wherein, The first calcination is carried out according to the following steps: (a) First heating stage: In an oxygen-deficient atmosphere with an oxygen concentration ≤ 10 vol%, heat up to T1 °C at a first heating rate ≥ 5 °C / min; (b) Second heating stage: In an atmosphere with an oxygen concentration ≥ 20 vol%, heat up to T2 °C at a second heating rate ≤ 1 °C / min; (c) Holding stage: Hold for t1 hours in the temperature range of T2 - 10 °C to T2 + 10 °C; wherein, T1 ranges from 600 °C ≤ T1 ≤ 850 °C; T2 is the first calcination temperature, 900 °C ≤ T2 ≤ 1100 °C; t1 is the first calcination time, 4 h ≤ t1 ≤ 15 h.

31. The preparation method according to claim 18 or 19, wherein, The second calcination is carried out according to the following steps: (A) First heating stage: In an oxygen-deficient atmosphere with an oxygen concentration ≤ 10 vol%, heat up to T3 °C at a first heating rate ≥ 5 °C / min; (B) Second heating stage: In an atmosphere with an oxygen concentration ≥ 20 vol%, heat up to T4 °C at a second heating rate ≤ 1 °C / min; (C) Holding stage: Hold for t2 hours in the temperature range of T4 - 10 °C to T4 + 10 °C; Among them, the range of T3 is 400°C ≤ T3 ≤ 800°C; T4 is the second calcination temperature, 700°C ≤ T4 ≤ 1000°C; t2 is the second calcination time, 4h ≤ t2 ≤ 15h.

32. The preparation method according to claim 18, wherein, the conditions of the first calcination include: the calcination temperature is 800 - 1000°C, and the calcination time is 4 - 10h.

33. The preparation method according to claim 18, wherein, the conditions of the second calcination include: the calcination temperature is 700 - 900°C, and the calcination time is 4 - 10h.

34. The preparation method according to claim 19, wherein, the conditions of the third calcination include: the calcination temperature is 700 - 950°C, and the calcination time is 4 - 10h.

35. The preparation method according to claim 18 or 19, wherein, the lithium cobaltate material precursor is prepared according to the following steps: (I) Prepare the first mixed salt solution by mixing cobalt salt and aluminum salt at a molar ratio of n(Co):n(Al)= a1 : b ; Preparing the first precipitating agent and the first complexing agent into a first precipitating agent solution and a first complexing agent solution respectively; (II) Simultaneously and respectively introducing the first mixed salt solution, the first precipitating agent solution and the first complexing agent solution into a reaction kettle to carry out a first reaction and a first aging to obtain a first solid-liquid mixture; (III) Filter-pressing the first solid-liquid mixture to obtain a filter cake, washing, drying and performing low-temperature heat treatment on the filter cake to obtain the lithium cobaltate material precursor.

36. The preparation method according to claim 18 or 19, wherein, the multi-component material precursor is prepared according to the following steps: (i) Prepare a second mixed salt solution with nickel salt, cobalt salt, and manganese salt in a molar ratio of n(Ni):n(Co):n(Mn)= x : y : z ; Prepare a second precipitating agent solution, a second complexing agent solution, and a dispersant solution by separately dissolving the second precipitating agent, the second complexing agent, and the dispersant, respectively. (ii) Simultaneously and respectively introducing the second mixed salt solution, the second precipitating agent solution, the second complexing agent solution and the dispersant solution into a reaction kettle to carry out a second reaction and a second aging to obtain a second solid-liquid mixture; (iii) Filter-pressing the second solid-liquid mixture to obtain a filter cake, washing and drying the filter cake to obtain the multi-component material precursor.

37. The preparation method according to claim 35, wherein, the conditions of the first reaction include: the reaction temperature is 40 - 70°C, and the pH value control range is 6.5 - 9.

5.

38. The preparation method according to claim 35, wherein, the time of the first aging is 2 - 12h.

39. The preparation method according to claim 36, wherein, the conditions of the second reaction include: the reaction temperature is 40 - 80°C, and the pH value control range is 7 - 13.

40. The preparation method according to claim 36, wherein, the time of the second aging is 2 - 8h.

41. The preparation method according to claim 35, wherein, the conditions of the low-temperature heat treatment include: treating at a temperature of 500 - 950°C for 1 - 5h in the presence of air and / or oxygen.

42. A blended lithium-ion battery cathode material prepared by the preparation method according to any one of claims 18 - 41.

43. A lithium-ion battery, characterized in that the lithium-ion battery contains the blended lithium-ion battery cathode material according to any one of claims 1 - 17 and 42.

44. The lithium-ion battery according to claim 43, wherein, In a coin-type lithium-ion battery using metallic Li as the negative electrode material and the blended lithium-ion battery cathode material as the positive electrode material, constant current and constant voltage charging is carried out under the conditions of 3 - 4.5 V, 0.1 C, 25 °C, and a cut-off current of 0.01 C. During the first-week charging process of the lithium-ion battery, the charging capacity at voltage ζ1 is Cap1, and the charging capacity at the end of charging is Cap2; wherein, 1 / 3α ≤ λ = Cap1 / Cap2 × 100% ≤ α, and ζ1 is the charging voltage of lithium cobaltate material charged to 1% SOC under the same test conditions; Based on the total weight of the blended lithium-ion battery cathode material, the weight ratio of the multi-component material is α.

45. The lithium-ion battery according to claim 43 or 44, wherein, In a coin-type lithium-ion battery using metallic Li as the negative electrode material and the blended lithium-ion battery cathode material as the positive electrode material, constant current and constant voltage charging is carried out under the conditions of 3 - 4.5 V, 0.1 C, 25 °C, and a cut-off current of 0.01 C. During the first-week charging process of the lithium-ion battery, the charging capacity at voltage ζ1 is Cap1, and the charging capacity at the end of charging is Cap2; wherein, 1 / 2α ≤ λ = Cap1 / Cap2 × 100% ≤ 3 / 4α, and ζ1 is the charging voltage of lithium cobaltate material charged to 1% SOC under the same test conditions; Based on the total weight of the blended lithium-ion battery cathode material, the weight ratio of the multi-component material is α.

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