Multi-component positive electrode material, method for producing the same, and lithium ion battery

Abstract

This application relates to the technical field of lithium-ion batteries, and discloses a multi-component cathode material, a method for manufacturing the same, and a lithium-ion battery. The surface of the multi-component cathode material includes dot-shaped coating and / or island-shaped coating, and the particle cumulative distribution of the multi-component cathode material is 1% particle size D 1 ≧0.7 μm, and the arithmetic mean roughness Ra of the coating measured by a three-dimensional scanning electron microscope of the multi-component cathode material satisfies 20 nm ≦ Ra ≦ 200 nm. The coverage rate Q of the dot-shaped coating and / or island-shaped coating of the multi-component cathode material satisfies 3% ≦ Q ≦ 30%. The surface of the multi-component cathode material includes dot-shaped coating and / or island-shaped coating, and the coating has a specific arithmetic mean roughness and coverage rate. In addition, the multi-component cathode material has a large particle size distribution D 1 to reduce the fine powder content in the multi-component cathode material and enable the lithium-ion battery including the cathode material to have excellent capacity and cycle performance.

Description

Technical Field

[0001] This application relates to the technical field of lithium - ion batteries, specifically to a multi - component cathode material, its manufacturing method, and a lithium - ion battery.

Background Art

[0002] In recent years, due to its high energy density, lithium - ion batteries have been widely used in portable electronic devices, electric vehicles, energy storage systems, etc. Although lithium - ion batteries are widely used, currently, electric vehicles still do not meet the needs of the majority of consumers compared to fuel - powered vehicles. The main reasons are problems such as the short driving range of electric vehicles, poor performance at low temperatures, and safety. The cathode material is the main limitation on the performance of lithium - ion batteries. The energy density of the graphite anode can reach 360 mAh / g, but the energy density of the cathode material, in the case of the ternary 622 material, is only 180 mAh / g. Moreover, the cathode material is the most expensive and heaviest main component in lithium - ion batteries. Therefore, improving the energy density and cycle stability of the cathode material can effectively reduce the weight and price of electric vehicles.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The purpose of this application is to provide a multi - component cathode material, its manufacturing method, and a lithium - ion battery to overcome the problem that the capacity and cycle performance of the cathode material for lithium - ion batteries existing in the prior art cannot meet the actual needs. The surface of the multi - component cathode material includes dot - shaped coating and / or island - shaped coating, and the coating has a specific arithmetic mean roughness and coverage rate. Also, the multi - component cathode material has a large particle size distribution D 1 so as to reduce the fine powder content in the multi - component cathode material and enable the lithium - ion battery containing the cathode material to have excellent capacity and cycle performance.

Means for Solving the Problem

[0004] To achieve the above object, in the first aspect of the present application, a multi-component cathode material is provided, and the surface of the multi-component cathode material includes dot-shaped coating and / or island-shaped coating. The particle cumulative distribution of the multi-component cathode material has a particle size D of 1% 1 ≧0.7 μm. The arithmetic mean roughness Ra of the coating measured by a three-dimensional scanning electron microscope of the multi-component cathode material satisfies 20 nm ≦ Ra ≦ 200 nm. The coverage rate Q of the dot-shaped coating and / or island-shaped coating of the multi-component cathode material satisfies 3% ≦ Q ≦ 30%.

[0005] In the second aspect of the present application, a method for manufacturing a multi-component cathode material is provided, and the method includes (1) Mixing a multi-component cathode material precursor, a first lithium source, and an optional dopant, and sintering at a first high temperature to obtain a multi-component cathode material process product 1. (2) After coarsely pulverizing the multi-component cathode material process product 1, washing it sequentially with an acid solution, washing it with water, and drying it to obtain a multi-component cathode material process product 2. (3) Mixing the multi-component cathode material process product 2, an optional second lithium source, and a coating agent, and performing a second high-temperature sintering to obtain the multi-component cathode material by sieving. The conditions for the acid solution washing are that the concentration of the acid solution is 0.01 to 0.05 g / mL, the washing time is 1 to 120 s, the sintering temperature T2 of the second high-temperature sintering is 200 to 1000 °C, and the addition amount of the coating agent is added according to the stoichiometric ratio 0 < [n(J)] / [n(Ni) + n(Co) + n(Mn)] ≦ 0.03.

[0006] In the third aspect of the present application, a multi-component cathode material manufactured by the above method is provided.

[0007] In the fourth aspect of the present application, a lithium-ion battery is provided, and the lithium-ion battery includes the multi-component cathode material.

[0008] According to the above technical solution, the multi-component cathode material, its manufacturing method, and the lithium-ion battery provided by this application have the following beneficial effects. The surface of the multi-component cathode material provided by this application includes dot-shaped coating and / or island-shaped coating, and the coating has a specific arithmetic mean roughness and coverage rate. Also, the multi-component cathode material has a large particle size distribution D 1 Thereby, reducing the fine powder content in the multi-component cathode material and enabling the lithium-ion battery containing the cathode material to have excellent capacity and cycle performance.

[0009] In the manufacturing method of the multi-component cathode material provided by this application, the method of washing with an acid solution is adopted to realize the dissociation of the multi-component cathode material process product 1 obtained by sintering at the first high temperature, achieving an excellent dissociation effect without generating fine powder, avoiding the generation of a large amount of fine powder caused by the conventional strong dissociation method, and further avoiding the reduction of the paste dispersibility, non-uniform coating, and the reduction of the cycle performance and storage performance of the lithium-ion battery due to the consumption of the electrolyte caused by the existence of excessive fine powder.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Best Mode for Carrying Out the Invention

[0011] The endpoints and any numerical values disclosed in the scope of this application are not limited to the precise ranges or numerical values, and it should be understood that these ranges or numerical values include numerical values close to these ranges or numerical values. For numerical ranges, between the endpoint values of individual ranges, between the endpoint values of individual ranges and single point values, and between single point values, one or more new numerical ranges can be obtained by combining them with each other, and these numerical ranges shall be regarded as specifically disclosed in this application.

[0012] In a first aspect of this application, a multi-component cathode material is provided, and the surface of the multi-component cathode material includes dot-shaped coatings and / or island-shaped coatings. The particle cumulative distribution of the multi-component cathode material is 1% particle size D 1 ≥ 0.7 μm, The arithmetic mean roughness Ra of the coating measured by a three-dimensional scanning electron microscope of the multi-component cathode material satisfies 20 nm ≤ Ra ≤ 200 nm. The coverage rate Q of the dot-shaped coating and / or island-shaped coating of the multi-component cathode material satisfies 3% ≤ Q ≤ 30%.

[0013] In the prior art, the multi-component cathode material is generally a hard block, and there is severe sticking between particles. After strong dissociation, fine powder is easily generated and may remain on the surface of the multi-component cathode material or be mixed into the multi-component cathode material. Therefore, in the manufacturing process of the battery, the dispersibility of the paste decreases, the coating is uneven, and the consumption of the fine powder electrolyte increases, thereby affecting the cycle performance and storage performance of the lithium-ion battery.

[0014] In this application, the fact that the multi-component cathode material has a large particle size distribution D 1 indicates that there are few particles with a small particle size in the multi-component cathode material, the fine powder content in the multi-component cathode material is low, and the lithium-ion battery including the cathode material has excellent capacity and cycle performance.

[0015] In addition, the surface coating of the positive electrode material can significantly improve the structural stability of the material. In the prior art, in order to improve the cycle and storage performance of lithium-ion batteries, many studies focus on the influence of coating element types on the material. However, the inventor of this application discovers through research that the coating amount and coating state of the surface coating of the multi-component positive electrode material also have a very important influence on the multi-component positive electrode material. Specifically, when the dot-shaped coating and / or island-shaped coating contained on the surface of the multi-component positive electrode material have the arithmetic mean roughness and coverage rate limited in this application, the lithium-ion battery manufactured by the multi-component positive electrode material has better electrical performance.

[0016] Furthermore, in this application, since the multi-component positive electrode material has a low fine powder content, it is possible to avoid the reduction of the effective coating due to the adsorption of excessive fine powder on the coating, thereby reducing the capacity of the lithium-ion battery including the multi-component positive electrode material. At the same time, in this application, since the multi-component positive electrode material has a low fine powder content, even when the usage amount of the coating agent is reduced, the lithium-ion battery manufactured by the multi-component positive electrode material can have excellent cycle performance and capacity.

[0017] In this application, the arithmetic mean roughness Ra of the coating of the multi-component positive electrode material is measured by the method of JIS B 0601(2001) using a three-dimensional scanning electron microscope (3D-SEM). The coverage rate of the coating is the total area of the dot-shaped coating and / or island-shaped coating within a 1μm 2 area on the surface of a single particle under an electron microscope divided by the area of the 1μm 2 area. As shown in the annotation area of the square frame in Figure 2, the average value is taken from the areas of 300 different particles.

[0018] In one preferred embodiment of this application, the particle cumulative distribution of the multi-component positive electrode material satisfies that the particle size of 1% is 1μm ≦ D 1 ≦ 2μm, and the arithmetic mean roughness Ra of the coating measured by the three-dimensional scanning electron microscope of the multi-component positive electrode material satisfies 30nm ≦ Ra ≦ 100nm. The coating rate Q of the dot-shaped coating and / or island-shaped coating of the multi-component cathode material satisfies 5% ≤ Q ≤ 15%.

[0019] According to this application, the particle cumulative distribution of the multi-component cathode material has a particle size D of 50% 50 of 2 - 8 μm, preferably 2.5 - 7 μm.

[0020] In this application, the particle size D of 1% of the particle cumulative distribution and the particle size D of 50% of the particle cumulative distribution of the multi-component cathode material 1 are measured by a laser particle size analyzer. 50 is measured by a laser particle size analyzer.

[0021] According to this application, the average size P of the multi-component cathode material measured by SEM 50 is 0.8 - 6 μm, preferably 1 - 4 μm.

[0022] According to this application, the specific surface area S of the multi-component cathode material is 0.2 m 2 / g ≤ S ≤ 1.2 m 2 / g, and / or, 1 / P 50 - 0.1 ≤ S ≤ 1 / P 50 + 0.2 is satisfied.

[0023] In this application, P 50 is in μm unit, S is in m 2 / g unit, and the above relationship is only a numerical relationship.

[0024] In this application, the multi-component cathode material has a large particle size distribution D 1 , a small specific surface area S, and the specific surface area S decreases with the increase of the average size P of the primary particles 50 , and there is an obvious correlation between the specific surface area S and the average size P of the primary particles 50 . The relationship between the macro index and the micro particle size is established. In particular, the specific surface area of the multi-component cathode material simultaneously satisfies 0.2 m 2 / g ≤ S ≤ 1.2 m 2 / g and 1 / P 50 - 0.1 ≤ S ≤ 1 / P 50Satisfying +0.2 indicates adopting appropriate dissociation conditions and appropriate coating annealing conditions in the process of manufacturing the positive electrode material. In the multi-component positive electrode material provided in this application, it shows that no fine powder is generated due to excessive dissociation, and there is no excessive sticking due to insufficient dissociation. Particle size distribution D 1 is too small (i.e., the fine powder content is high), the specific surface area S of the multi-component positive electrode material becomes too large, and when there is excessive sticking due to insufficient dissociation, the specific surface area S of the multi-component positive electrode material becomes small, and there is no good calculation relationship that can be established between the specific surface area S and the average primary particle size P 50

[0025] In this application, in addition, the surface coating situation also affects the specific surface area of the material. If the surface coating remains excessively, the specific surface area becomes large; if the surface coating hardly remains, the specific surface area becomes small. The above relationship holds only when the surface coating remains within an appropriate range, and the electrochemical performance of the multi-component positive electrode material is good.

[0026] Furthermore, the specific surface area S of the multi-component positive electrode material satisfies 0.3m 2 / g ≦ S ≦ 1m 2 / g, and / or 1 / P 50 -0.05 ≦ S ≦ 1 / P 50 +0.05.

[0027] In one preferred embodiment of this application, the specific surface area S of the multi-component positive electrode material satisfies 0.2m 2 / g ≦ S ≦ 1.2m 2 / g, and 1 / P 50 -0.1 ≦ S ≦ 1 / P 50 +0.2, preferably, 0.3m 2 / g ≦ S ≦ 1m 2 / g, and 1 / P 50 -0.05 ≦ S ≦ 1 / P 50 +0.05.

[0028] According to this application, the multi-component positive electrode material is spherical and / or ellipsoidal particles.

[0029] ​According to the present application, the base of the multi-component cathode material has a structure represented by Formula I, and the coating contains a J element-containing lithium oxygen compound and / or a J element-containing oxide. Li a Ni x Mn y Co z M b O 2 Formula I. Among them, 0.9 ≦ a ≦ 1.1, 0.5 ≦ x < 1, 0 < y < 0.5, 0 < z < 0.5, 0 ≦ b ≦ 0.02, Due to the contents of the base and the coating, 0 < [n(J)] / [n(Ni) + n(Co) + n(Mn)] ≦ 0.03 in the cathode material, M and J are each independently selected from at least one of Ba, Ra, Zr, Fe, Ca, Zn, B, W, Nb, Cd, Pb, Si, Mo, Cu, V, Ta, Cr, La, Al, Ce, Er, Ho, Y, Mg, Sr, and Ti.

[0030] In the present application, among the J element-containing lithium oxygen compound and / or the J element-containing oxide, there may also be included at least one element from Ni, Co, Mn, and M from the base.

[0031] Furthermore, 1 ≦ a ≦ 1.06, 0.6 ≦ x < 1, 0 ≦ y ≦ 0.4, 0 ≦ z ≦ 0.4, 0.001 ≦ b ≦ 0.01, Due to the contents of the base and the coating, 0.001 ≦ [n(J)] / [n(Ni) + n(Co) + n(Mn)] ≦ 0.01 in the cathode material, M and J are each independently selected from at least one of Ba, Zr, B, W, Nb, La, Al, Y, Mg, Sr, and Ti.

[0032] In the second aspect of the present application, a method for manufacturing a multi-component cathode material is provided, and the method includes: (1) Mixing a multi-component cathode material precursor, a first lithium source, and an optional dopant, and sintering at a first high temperature to obtain a multi-component cathode material process product 1, (2) After coarsely pulverizing the multi-component cathode material process product 1, it is sequentially washed with an acid solution, washed with water, and dried to obtain a multi-component cathode material process product 2. (3) The multi-component cathode material process product 2, a selectable second lithium source, and a coating agent are mixed and sintered at a second high temperature, and then sieved to obtain the multi-component cathode material. The conditions for the acid solution washing are that the concentration of the acid solution is 0.01 to 0.05 g / mL, and the washing time is 1 to 120 s. The sintering temperature T2 of the second high-temperature sintering is 200 to 1000 °C. The addition amount of the coating agent is added according to the stoichiometric ratio 0 < [n(J)] / [n(Ni) + n(Co) + n(Mn)] ≤ 0.03.

[0033] In the prior art, during the manufacturing process of the multi-component cathode material, since the primary sintering temperature is high, hard blocks are likely to be formed after sintering, and the adhesion between particles is severe, and it is necessary to dissociate by a strong dissociation method. The strong dissociation method is likely to generate fine powder.

[0034] In the present application, in the manufacturing method of the multi-component cathode material, the method of washing with an acid solution is adopted to realize the dissociation of the multi-component cathode material process product 1 obtained by sintering at the first high temperature, achieve an excellent dissociation effect, and do not generate fine powder, avoiding the generation of a large amount of fine powder caused by the conventional strong dissociation method. Furthermore, it avoids the reduction of the cycle performance and storage performance of the lithium-ion battery due to the decrease in the dispersibility of the paste, non-uniform coating, and consumption of the electrolyte caused by the presence of excessive fine powder.

[0035] Furthermore, since the acid solution cleaning corrodes the surface of the polyanode material process product 1, the surface roughness of the obtained polyanode material process product 2 increases. At the same time, since there are no adhering particles on the surface of the polyanode material process product 2, after mixing with the coating agent and performing the second high-temperature sintering, the bonding between the coating and the surface of the manufactured polyanode material is tighter. Moreover, during the cycling process of the lithium-ion battery, the coating is less likely to fall off from the surface of the anode material, achieving a better coating effect. In particular, by controlling the conditions of the acid solution cleaning to meet the above range, the particles of the obtained polyanode material can be separated from each other and no fine powder is generated. Specifically, if the concentration of the acid solution is too low or the cleaning time is too short, the separation effect cannot be achieved. If the concentration of the acid solution is too high or the cleaning time is too long, the composition of the polyanode material surface will be damaged, and ultimately the performance of the lithium-ion battery containing the polyanode material will decline.

[0036] Furthermore, in the present application, by washing the polyanode material process product 1 with an acid solution, the polyanode material has a low fine powder content. Even when the usage amount of the coating agent is reduced, the lithium-ion battery of the polyanode material provided in the present application can ensure excellent cycle performance and capacity.

[0037] In the present application, the polyanode material process product 2 is a sphere and / or ellipsoidal particle with good independence.

[0038] Also, by adopting the acid solution cleaning, lithium carbonate and lithium hydroxide remaining on the surface of the polyanode material process product 1 are washed away, the surface residue of the obtained polyanode material decreases, and the surface layer is more likely to be lithium-deficient. Therefore, a second lithium source is added during the second high-temperature sintering process to ensure that the lithium-ion battery containing the obtained polyanode material has a high capacity. Furthermore, the second lithium source has the effect of assisting solubility. By adding the second lithium source during the second high-temperature sintering process, the temperature of the second high-temperature sintering can be reduced, and energy consumption can be reduced.

[0039] According to the present application, the multi-component cathode material precursor is a nickel, cobalt, manganese ternary cathode material precursor.

[0040] In the present application, the multi-component cathode material precursor can be purchased commercially or can also be manufactured by oneself.

[0041] According to the present application, the first lithium source and the second lithium source are each independently selected from lithium carbonate, lithium hydroxide, lithium oxide, and lithium acetate.

[0042] According to the present application, the dopant and the coating agent are each independently selected from carbonates, hydroxides, oxides, and acetates that can provide at least one element from among Ba, Ra, Zr, Fe, Ca, Zn, B, W, Nb, Cd, Pb, Si, Mo, Cu, V, Ta, Cr, La, Al, Ce, Er, Ho, Y, Mg, Sr, and Ti.

[0043] According to the present application, the acid solution is selected from at least one of sulfuric acid, carbonic acid, acetic acid, and oxalic acid.

[0044] According to the present application, the total addition amount of the first lithium source and the second lithium source is added according to the stoichiometric ratio of 0.9 ≦ [n(Li 1 ) + n(Li 2 )] / [n(Ni) + n(Co) + n(Mn)] ≦ 1.1.

[0045] Furthermore, the total addition amount of the first lithium source and the second lithium source is added according to the stoichiometric ratio of 1 ≦ [n(Li 1 ) + n(Li 2 )] / [n(Ni) + n(Co) + n(Mn)] ≦ 1.06.

[0046] In the present application, the addition amount of each of the first lithium source and the second lithium source has no special limitation, and it is only necessary that the total addition amount of the first lithium source and the second lithium source satisfies the above range.

[0047] In one specific embodiment of the present application, the addition amount of the first lithium source is added according to the stoichiometric ratio of 0.9 ≦ [n(Li 1 )] / [n(Ni) + n(Co) + n(Mn)] ≦ 1.05, and the addition amount of the second lithium source is added according to the stoichiometric ratio of 0 ≦ [n(Li 2 )] / [n(Ni) + n(Co) + n(Mn)] ≦ 0.05.

[0048] In one preferred embodiment of the present application, the addition amount of the first lithium source is added according to the stoichiometric ratio of 0.99 ≦ [n(Li 1 )] / [n(Ni) + n(Co) + n(Mn)] ≦ 1.05, and the addition amount of the second lithium source is added according to the stoichiometric ratio of 0.01 ≦ [n(Li 2 )] / [n(Ni) + n(Co) + n(Mn)] ≦ 0.01.

[0049] According to the present application, the addition amount of the dopant is added according to the stoichiometric ratio of 0 ≦ [n(M)] / [n(Ni) + n(Co) + n(Mn)] ≦ 0.02, preferably 0 ≦ [n(M)] / [n(Ni) + n(Co) + n(Mn)] ≦ 0.01.

[0050] According to the present application, the addition amount of the coating agent is added according to the stoichiometric ratio of 0 < [n(J)] / [n(Ni) + n(Co) + n(Mn)] ≦ 0.03.

[0051] In this application, when the addition amount of the coating agent is controlled to meet the above range, the obtained multi-component cathode material has an appropriate content of coating, and thus the obtained multi-component cathode material is ensured to have a stable structure and no excessive coating remains on the surface. Specifically, when the addition amount of the coating agent is too high, there is too much coating remaining on the surface of the material, which affects the transmission of lithium ions, reduces the capacity and rate performance of the lithium-ion battery including the multi-component cathode material. When the addition amount of the coating agent is too low, the role of the coating cannot be fulfilled, and during the cycling process, the electrolyte is likely to damage the surface structure of the multi-component cathode material, resulting in a decrease in the performance of the lithium-ion battery including the multi-component cathode material.

[0052] According to this application, the addition amount of the coating agent is added according to the stoichiometric ratio of 0.001 ≦ [n(J)] / [n(Ni) + n(Co) + n(Mn)] ≦ 0.01.

[0053] According to this application, the conditions for the first high-temperature sintering are that the sintering temperature T 1 is 700 - 1200 °C, the sintering time is 10 - 30 h, and the sintering atmosphere includes oxygen and / or air.

[0054] Furthermore, the conditions for the first high-temperature sintering are that the sintering temperature T 1 is 700 - 1050 °C, the sintering time is 15 - 25 h, and the sintering atmosphere includes oxygen and / or air.

[0055] According to this application, the conditions for the acid solution washing include that the concentration of the acid solution is 0.02 - 0.04 g / mL and the washing time is 5 - 60 s.

[0056] In this application, the coarse pulverization may be carried out by a conventional method well-known to those skilled in the art, aiming to decompose large blocks into small blocks, with weak dissociation strength and little generation of fine powder. For example, it is double-roll dissociation with wide gaps.

[0057] In this application, the purpose of washing the product with water after acid solution washing is to remove the remaining acid solution.

[0058] According to this application, the sintering temperature of the second high-temperature sintering is 300 - 900 °C.

[0059] According to this application, the sintering time of the second high-temperature sintering is 5 - 20 h, preferably 6 - 15 h.

[0060] According to this application, the second high-temperature sintering is carried out in air and / or oxygen.

[0061] According to this application, the sintering temperature T of the second high-temperature sintering 2 is 200 - 1000 °C, and the sintering temperature T 2 and the melting point T of the coating agent m satisfy the following relationship. 100 × lnT m -200 ≤ T 2 ≤ 100 × lnT m + 100.

[0062] In this application, the applicant adjusts the sintering temperature of the second high-temperature sintering according to the difference in the type of coating agent, so that the coating effect of the coating agent on the positive electrode material is better realized. Specifically, by controlling that the relationship between the melting point of the coating agent and the sintering temperature of the second high-temperature sintering is satisfied, it is found by research that a better coating effect can be obtained.

[0063] Furthermore, the sintering temperature T of the second high-temperature sintering 2 is 300 - 900 °C, and the sintering temperature T 2 and the melting point T of the coating agent m satisfy the following relationship. 100 × lnT m -100 ≤ T 2 ≤ 100 × lnT m + 50.

[0064] In a third aspect of the present application, a multi-component cathode material manufactured by the above manufacturing method is provided.

[0065] In a fourth aspect of the present application, a lithium-ion battery is provided, and the lithium-ion battery includes the multi-component cathode material.

[0066] Hereinafter, the present application will be described in detail by way of examples. In the following examples, unless otherwise specified, all raw materials are commercially available products.

[0067] Unless otherwise specified, room temperature in the present application refers to 25 ± 2°C.

[0068] In the following examples and comparative examples, the relevant parameters are measured by the following methods. (1) Particle size measurement: Laser particle size analyzer. (2) Morphology and surface roughness measurement: ERA-9200 scanning electron microscope manufactured by ELIONIX, Japan. (3) Specific surface area measurement: Tristar 3020 specific surface area analyzer manufactured by Micromeritics. (4) Electrochemical performance measurement: In the following examples and comparative examples, the electrochemical performance of the multi-component cathode material is measured using a 2025 coin cell.

[0069] The manufacturing process of the 2025 coin cell is specifically as follows. Electrode sheet manufacturing: The multi-component cathode material, acetylene black, and polyvinylidene fluoride (PVDF) are mixed in a mass ratio of 95:3:2 with an appropriate amount of N-methylpyrrolidone (NMP) to form a uniform paste. The paste is coated on an aluminum foil and dried at 120°C for 12 h, and then punched and formed under a pressure of 100 MPa to manufacture a positive electrode sheet with a diameter of 12 mm and a thickness of 120 μm. Among them, the loading amount of the multi-component cathode material is 15 mg / cm 2 is.

[0070] Battery assembly: Inside a gas glove box filled with argon gas with a moisture content and an oxygen content both less than 5 ppm, the positive electrode plate, diaphragm, negative electrode plate, and electrolyte are assembled into a 2025-type coin cell and left standing for 6 h. Among them, a metal lithium sheet with a diameter of 17 mm and a thickness of 1 mm is used for the negative electrode plate, a porous polyethylene film (Celgard 2325) with a thickness of 25 μm is used for the diaphragm, and the electrolyte is an equal-volume mixture of ethylene carbonate (EC) and diethylene carbonate (DEC) containing 1 mol / L LiPF 6 is an equal-volume mixture of ethylene carbonate (EC) and diethylene carbonate (DEC) containing 1 mol / L LiPF

[0071] Electrochemical performance measurement: In the following examples and comparative examples, the electrochemical performance of the 2025-type coin cell was measured using a deep-sensing Neware battery test system, and the charge-discharge current density at 0.1C was 200 mA / g.

[0072] The charge-discharge voltage range was controlled to 3.0 - 4.3 V, and the coin cell was charged and discharged at 0.1C at room temperature to evaluate the initial charge-discharge specific capacity and the initial charge-discharge efficiency of the multi-component positive electrode material.

[0073] Cycle performance measurement: The charge-discharge voltage range was controlled to 3.0 - 4.3 V, and the coin cell was charged and discharged at 0.1C for 2 cycles at a constant temperature of 45°C and charged and discharged at 1C for 80 cycles to evaluate the high-temperature capacity retention rate of the multi-component positive electrode material.

[0074] Rate performance measurement: The charge-discharge voltage range was controlled to 3.0 - 4.3 V, and the coin cell was charged and discharged at 0.1C for 2 cycles at room temperature, and then charged and discharged at 0.2C, 0.33C, 0.5C, and 1C for 1 cycle each. Based on the ratio of the 0.1C initial discharge specific capacity and the 1C discharge specific capacity, the rate performance of the multi-component positive electrode material was evaluated. Among them, the 0.1C initial discharge specific capacity is the discharge specific capacity of the first cycle of the coin cell, and the 1C discharge specific capacity is the discharge specific capacity of the sixth cycle of the coin cell.

[0075] Example 1 This example describes the positive electrode material manufactured using the method of this application. (1) Nickel, cobalt, manganese hydroxide precursor Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 , lithium hydroxide, aluminum oxide are uniformly mixed according to the ratio of n(Li):n(Al):[n(Ni)+n(Co)+n(Mn)] = 1.04:0.001:1, sintered at 890 °C for 20 h in an oxygen atmosphere, and naturally cooled to room temperature to obtain the multi-component cathode material process product 1. (2) The multi-component cathode material process product 1 is coarsely pulverized, washed with 0.03 g / mL sulfuric acid for 30 s, and washed with deionized water to remove the residual sulfuric acid. After drying, the multi-component cathode material process product 2, Li 1.04 Ni 0.8 Co 0.1 Mn 0.1 Al 0.001 O 2 is obtained. (3) The multi-component cathode material process product 2, lithium hydroxide, magnesium oxide, tungsten oxide are uniformly mixed according to the ratio of n(Li):n(Mg):n(W):[n(Ni)+n(Co)+n(Mn)] = 0.01:0.005:0.002:1, sintered at 700 °C for 12 h in an oxygen atmosphere, and naturally cooled to room temperature, and then sieved to obtain the multi-component cathode material.

[0076] Examples 2 - 7 By the method of Example 1, however, the formulation and technical parameters are different, and the specific content is shown in Tables 1-1 and 1-2. Otherwise, the multi-component cathode material is obtained in the same manner as in Example 1.

Table 1-1

Table 1-2

[0077] Comparative Example 1 (1) Nickel, cobalt, manganese hydroxide precursor Ni 0.8 Co 0.1 Mn 0.1 (OH) 2, Lithium hydroxide and aluminum oxide are uniformly mixed according to the ratio of n(Li):n(Al):[n(Ni)+n(Co)+n(Mn)] = 1.04:0.001:1, sintered at 890 °C for 20 h in an oxygen atmosphere, and naturally cooled to room temperature to obtain the multi-component cathode material process product 1. (2) The multi-component cathode material process product 1 is coarsely pulverized and dissociated using a double roll with a narrow gap until the target particle size reaches 6.2 μm to obtain the multi-component cathode material process product 2, which is Li 1.04 Ni 0.8 Co 0.1 Mn 0.1 Al 0.001 O 2 . (3) The multi-component cathode material process product 2, lithium hydroxide, magnesium oxide, and tungsten oxide are uniformly mixed according to the ratio of n(Li):n(Mg):n(W):[n(Ni)+n(Co)+n(Mn)] = 0.01:0.005:0.002:1, sintered at 700 °C for 12 h in an oxygen atmosphere, naturally cooled to room temperature, and sieved to obtain the multi-component cathode material.

[0078] Comparative Example 2 According to the method of Example 1, the difference is that in step (3), the multi-component cathode material process product 2 and lithium hydroxide are uniformly mixed according to the ratio of n(Li):[n(Ni)+n(Co)+n(Mn)] = 0.01:1, and the rest is the same as in Example 1 to obtain the multi-component cathode material, which is Li 1.05 Ni 0.8 Co 0.1 Mn 0.1 Al 0.001 O 2 . The measured data of the characteristic parameters are shown in Tables 2-1 and 2-2.

[0079] Comparative Example 3 According to the method of Example 1, the difference is that in step (3), the ternary material process product 2, lithium hydroxide, magnesium oxide, and tungsten oxide are uniformly mixed according to the ratio of n(Li):n(Mg):n(W):[n(Ni)+n(Co)+n(Mn)] = 0.01:0.03:0.03:1, and sintered at 400 °C for 12 h in an oxygen atmosphere. Otherwise, it is the same as Example 1 to obtain a multi-component cathode material. The measurement data of the characteristic parameters are shown in Tables 2-1 and 2-2.

[0080] Comparative Example 4 According to the method of Example 1, the difference is that in step (3), it is sintered at 1100 °C in an oxygen atmosphere. Otherwise, it is the same as Example 1 to obtain a multi-component cathode material. The measurement data of the characteristic parameters are shown in Tables 2-1 and 2-2.

[0081] Comparative Example 5 According to the method of Example 1, the difference is that in step (2), it is washed with 0.1 g / mL sulfuric acid for 180 s. Otherwise, it is the same as Example 1 to obtain a multi-component cathode material. The measurement data of the characteristic parameters are shown in Tables 2-1 and 2-2.

[0082] Measurement Example (1) Morphology measurement In this application, the scanning electron microscope images of the cathode materials manufactured in the above examples and comparative examples were measured, and the average primary particle size P of the multi-component cathode material 50 , the arithmetic mean roughness Ra, and the coverage rate Q were statistically analyzed and are shown in Figures 1-4 and Tables 2-1 and 2-2. From Figure 1, it can be seen that there is no adhesion on the surface of the multi-component cathode material process product 2 obtained in Example 1, and the particle independence is good. The surface of the multi-component cathode material in Figure 2 has dot-shaped and island-shaped coatings. The surface of the multi-component cathode material process product 2 obtained in Comparative Example 1 has a lot of fine powder, many fragments, and the corners are worn. There is also a lot of fine powder on the surface of the multi-component cathode material in addition to the coating. (2) Physical property measurement In this application, the D of the multi-component cathode materials manufactured in the above examples and comparative examples 1 , D 50 , P 50Measure S, Ra, and Q, and the specific details are shown in Tables 2-1 and 2-2.

Table 2-1

Table 2-2

[0083] From Tables 2-1 and 2-2, compared with Example 1, in Example 2, the sulfuric acid concentration is low and the washing time is short, so the obtained S is small, the dissociation is insufficient, and particle adhesion is observed. In Example 3, the sulfuric acid concentration is high and the washing time is long, so the obtained S is large, and D 50 and P 50 become small, indicating that the surface of the positive electrode material is partially corroded by sulfuric acid.

[0084] Compared with Example 1, in Example 4, the coating amount is large, so there is more coating agent remaining on the surface, and S, Ra, and Q become large. In Example 5, because the second high-temperature sintering temperature is high, the coating agent is mostly mixed into the outer layer of the positive electrode material, with less remaining on the surface, and S, Ra, and Q become small.

[0085] Examples 6 and 7 show that different configurations and coating agents are also applicable.

[0086] Compared with Example 1, in Comparative Example 1, dissociation is carried out using a double roll to the target particle size, and there is a lot of fine powder generated by dissociation, D 1 is small, S is large, the surface is rough, and Ra is large. This is consistent with the results in Figures 3 and 4.

[0087] In Comparative Example 2, no coating was performed, and after sintering at the second high temperature, the particles slightly adhered, resulting in a small S. In Comparative Example 3, the coating amount was too large and the second high-temperature sintering temperature was low, so more coating agents remained on the surface, resulting in a very large S, and the surface roughness Ra and surface coverage Q increased. In Comparative Example 4, since the second high-temperature sintering temperature was high, all the coating agents were mixed into the outer layer of the positive electrode material, and the particles adhered, resulting in a very small S.

[0088] In Comparative Example 5, the concentration of the acid solution was high and the washing time was long, so the surface was severely corroded, and D 50 and P 50 became small and S became large.

Table 3

[0089] From Table 3, compared with Example 1, the S of Example 2 was small, the particles adhered, the material capacity was slightly low, and the rate and cycle performance decreased slightly. The S of Example 3 was large, the surface was partially corroded, and the cycle performance of the material was poor.

[0090] Compared with Example 1, in Example 4, since the coating amount was large, more coating agents remained on the surface, the transmission of lithium ions was hindered, the material capacity decreased, the rate decreased, and the cycle decreased slightly. In Example 5, the second high-temperature sintering temperature was high, the coating agents remaining on the surface were few, and the cycle became worse. In Example 8, the second lithium source was not included, the surface was lithium-deficient, and the capacity was low.

[0091] Compared with Example 1, in Comparative Example 1, there were many fine powders, more electrolyte was consumed, the electrolyte was insufficient, as a result, the material capacity decreased, and the fine powders made the battery electrode plate unstable and the cycle became worse.

[0092] In Comparative Example 2, no coating is performed, and structural changes are likely to occur on the surface during the battery charge and discharge process, resulting in a decrease in cycle performance. In Comparative Example 3, there is a large amount of residue on the surface, which hinders the transmission of lithium ions and reduces the rate performance of the material. In Comparative Example 4, the second high-temperature sintering temperature is high, the residue of the coating agent is small, and the particles are adhered, resulting in poor cycle stability of the material.

[0093] In Comparative Example 5, the concentration of the acid solution is too high and the washing time is long, so the material is severely corroded and the cycle stability is reduced.

[0094] The preferred embodiments of the present application have been described in detail above, but the present application is not limited thereto. Within the technical concept scope of the present application, the technical solutions of the present application can be subjected to various simple modifications, including combining individual technical features in any other appropriate manner. These simple modifications and combinations are also regarded as the content disclosed by the present application and are included in the protection scope of the present application.

Claims

1. A multi-component cathode material, wherein the surface of the multi-component cathode material includes dot-shaped coating and / or island-shaped coating, The particle cumulative distribution of the above-mentioned multi-component positive electrode material has a particle size D of 1% １ ≧0.7 μm, and the arithmetic mean roughness Ra of the coating measured by a three-dimensional scanning electron microscope of the multi-component cathode material satisfies 20 nm ≤ Ra ≤ 200 nm, and the coverage rate Q of the dot-shaped coating and / or island-shaped coating of the multi-component cathode material satisfies 3% ≤ Q ≤ 30%. A multi-component cathode material characterized by this.

2. The particle cumulative distribution of the above-mentioned multi-component positive electrode material satisfies 1% particle size of 1 μm ≤ D １ ≤ 2 μm, The arithmetic mean roughness Ra of the coating measured by a three-dimensional scanning electron microscope of the multi-component cathode material satisfies 30 nm ≤ Ra ≤ 100 nm, and the coverage rate Q of the dot-shaped coating and / or island-shaped coating of the multi-component cathode material satisfies 5% ≤ Q ≤ 15%. The multi-component cathode material according to claim 1, characterized by this.

3. The particle cumulative distribution of the above-mentioned multi-component positive electrode material has a particle size D of 50% ５０ being 2 to 8 μm, preferably 2.5 to 7 μm, Preferably, the average dimension P measured by SEM of the multi-component cathode material is 0.8 to 6 μm, preferably 1 to 4 μm, ５０ and Preferably, the specific surface area S of the multi-component positive electrode material satisfies 0.2 m ２ / g ≤ S ≤ 1.2 m ２ / g, and / or 1 / P ５０ −0.1 ≤ S ≤ 1 / P ５０ +0.2, Preferably, the multi-component cathode material is spherical and / or ellipsoidal particles. The multi-component cathode material according to claim 1 or 2, characterized by this.

4. The base of the multi-component cathode material has a structure represented by Formula I, and the coating includes a J element-containing lithium oxygen compound and / or a J element-containing oxide, Li ａ Ni ｘ Mn ｙ Co ｚ M ｂ O ２ Formula I wherein 0.9 ≤ a ≤ 1.1, 0.5 ≤ x < 1, 0 < y < 0.5, 0 < z < 0.5, 0 ≤ b ≤ 0.02, due to the contents of the base and the coating, 0 < [n(J)] / [n(Ni) + n(Co) + n(Mn)] ≤ 0.03 in the cathode material, and M and J are each independently selected from at least one of Ba, Ra, Zr, Fe, Ca, Zn, B, W, Nb, Cd, Pb, Si, Mo, Cu, V, Ta, Cr, La, Al, Ce, Er, Ho, Y, Mg, Sr, and Ti. The multi-component cathode material according to any one of claims 1 to 3, characterized by this.

5. A method for manufacturing a multi-component cathode material, the method comprising: mixing a multi-component cathode material precursor, a first lithium source, and an optional dopant, and performing a first high-temperature sintering to obtain a multi-component cathode material process product 1; after coarsely pulverizing the multi-component cathode material process product 1, sequentially washing with an acid solution, washing with water, and drying to obtain a multi-component cathode material process product 2; mixing the multi-component cathode material process product 2, an optional second lithium source, and a coating agent, and performing a second high-temperature sintering and sieving to obtain the multi-component cathode material; the conditions for washing with the acid solution are that the concentration of the acid solution is 0.01 - 0.05 g / mL and the washing time is 1 - 120 s. The sintering temperature T of the second high-temperature sintering ２ is 200 to 1000 °C, and The method is characterized by including that the addition amount of the coating agent is added according to the stoichiometric ratio of 0 < [n(J)] / [n(Ni) + n(Co) + n(Mn)] ≤ 0.

03.

6. The multi-component cathode material precursor is a nickel, cobalt, manganese ternary cathode material precursor, Preferably, the first lithium source and the second lithium source are each independently selected from lithium carbonate, lithium hydroxide, lithium oxide, and lithium acetate. Preferably, the dopant and the coating agent are each independently selected from a carbonate, hydroxide, oxide, and acetate capable of providing at least one element from Ba, Ra, Zr, Fe, Ca, Zn, B, W, Nb, Cd, Pb, Si, Mo, Cu, V, Ta, Cr, La, Al, Ce, Er, Ho, Y, Mg, Sr, and Ti. Preferably, the acid solution is selected from at least one of sulfuric acid, carbonic acid, acetic acid, and oxalic acid. The method according to claim 5 is characterized by this.

7. The total addition amount of the first lithium source and the second lithium source is added according to the stoichiometric ratio of 0.9 ≤ [n(Li1) + n(Li2)] / [n(Ni) + n(Co) + n(Mn)] ≤ 1.1, preferably 1 ≤ [n(Li1) + n(Li2)] / [n(Ni) + n(Co) + n(Mn)] ≤ 1.

06. Preferably, the addition amount of the dopant is added according to the stoichiometric ratio of 0.0001 ≤ [n(M)] / [n(Ni) + n(Co) + n(Mn)] ≤ 0.02, preferably 0.001 ≤ [n(M)] / [n(Ni) + n(Co) + n(Mn)] ≤ 0.

01. Preferably, the addition amount of the coating agent is added according to the stoichiometric ratio of 0.001 < [n(J)] / [n(Ni) + n(Co) + n(Mn)] ≤ 0.

01. The method according to claim 6 is characterized by this.

8. The conditions for the first high-temperature sintering are that the sintering temperature T １ is 700 to 1200 °C, the sintering time is 10 to 30 h, and the sintering atmosphere includes oxygen and / or air, Preferably, the conditions for washing with the acid solution include that the concentration of the acid solution is 0.02 - 0.04 g / mL and the washing time is 5 - 60 s. Preferably, the sintering temperature T of the second high-temperature sintering ２ is 300 to 900 °C, Preferably, the sintering time of the second high-temperature sintering is 5 - 20 h, preferably 6 - 15 h. Preferably, the second high-temperature sintering is performed with air and / or oxygen. The method according to any one of claims 5 - 7 is characterized by this.

9. The sintering temperature T of the second high-temperature sintering ２ is 200 to 1000 °C, and the sintering temperature T ２ and the melting point T of the coating agent ｍ satisfy the following relationship 100 × ln T ｍ -200 ≤ T ２ ≤ 100 × ln T ｍ +100 Preferably, the sintering temperature T of the second high-temperature sintering ２ is 300 to 900 °C, and the sintering temperature T ２ and the melting point Tm of the coating agent satisfy the following relationship: 100 × ln T ｍ -100 ≤ T ２ ≤ 100 × ln T ｍ +50, wherein the method according to any one of claims 5 to 8 is characterized by this.

10. A multi-component cathode material obtained by the method according to any one of claims 5 - 9.

11. A lithium-ion battery, wherein the lithium-ion battery includes the multi-component cathode material according to any one of claims 1 to 4 and 10, characterized in that it is a lithium-ion battery.

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