Single-crystal cathode material and method for manufacturing the same, sodium-ion battery

Abstract

The single-crystal granules of the single-crystal cathode material have a specific granule size distribution, the single-crystal cathode material has a high pressure density, and in addition, a high Young's modulus, which allows it to withstand higher rolling pressure during battery manufacturing, thereby increasing the volumetric energy density of the lithium-ion battery equipped with the cathode material. The present invention relates to the technical field of sodium-ion batteries, and more particularly to a single-crystal cathode material, a method for manufacturing the same, and a sodium-ion battery. Size distribution of single-crystal granules of the single-crystal cathode material B 90 =(P 90 -P 10 ) / P 50 However, 0.9 ≤ B 90 The condition ≤ 1.4 is satisfied. The Young's modulus E of the positive electrode material, measured using an atomic force microscope, satisfies the condition 100 GPa ≤ E ≤ 200 GPa.

Description

[Technical Field]

[0001] The present invention relates to the technical field of sodium-ion batteries, and more particularly to single-crystal cathode materials, methods for producing the same, and sodium-ion batteries. [Background technology]

[0002] With the rapid development of the power battery industry, the market demand for lithium-ion batteries is increasing. Large-volume automotive batteries occupy space in electric vehicles, significantly limiting vehicle comfort and design. The cathode material, as the most important element in a battery, has the potential to reduce battery volume by increasing its volumetric energy density. Currently, existing technology typically increases battery energy density by raising the operating potential window, but as the voltage increases, battery performance deteriorates significantly, leading to problems such as electrode fragmentation, rapid loss of circulation performance, and gas generation. Furthermore, the ease with which existing electrolytes oxidize and decompose under high voltage limits the further development of this technological method.

[0003] Increasing the pressure density of the positive electrode material allows for the compression of more positive electrode material per unit space, while also saving space. Increasing the pressure density means applying more pressure to the granules of the positive electrode material during the manufacturing of the electrode piece. If the material granules do not have sufficient strength, they are more likely to rupture and even break under such pressure. [Overview of the project] [Problems that the invention aims to solve]

[0004] This invention aims to overcome the problem that the pressure density and granular strength of cathode materials in current technology do not meet the requirements by proposing a single-crystal cathode material, a method for manufacturing the same, and a sodium-ion battery. Specifically, the single-crystal granules of the single-crystal cathode material have a specific granular size distribution, the single-crystal cathode material has a high pressure density, and in addition, a high Young's modulus, thereby enabling it to withstand higher rolling pressure during battery manufacturing, and thereby increasing the volumetric energy density of the lithium-ion battery equipped with the cathode material. [Means for solving the problem]

[0005] To achieve the above objective, the first embodiment of the present invention proposes a single-crystal cathode material.

[0006] Size distribution of single crystal granules in single crystal cathode material B 90 =(P 90 -P 10 ) / P 50 However, 0.9 ≤ B 90 It satisfies ≤ 1.4.

[0007] The above formula includes P 10 This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 10% of the positive electrode material in the SEM image, P 50 This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample in the SEM image of the cathode material where the percentage reached 50%, and P 90 This represents the particle size corresponding to the cumulative single-crystal granule size distribution of the sample in the SEM image of the cathode material, where the percentage reached 90%.

[0008] The Young's modulus E of the cathode material, measured using an atomic force microscope, satisfies the condition 100 GPa ≤ E ≤ 200 GPa.

[0009] In a second aspect of the present invention, a method for manufacturing a single-crystal cathode material is proposed. The manufacturing method includes the following steps.

[0010] Mixture I is obtained by mixing S1, a nickel-cobalt-manganese precursor, and a lithium source with a G element-containing additive of a selectable nature.

[0011] S2, performing a first sintering of the mixture I in an oxygen-containing atmosphere, followed by crushing, to obtain semi-finished product II of a single-crystal cathode material.

[0012] S3, mixing the semi-finished product II of the single-crystal cathode material with a selectable element M-containing coating agent to obtain mixture III.

[0013] S4, performing a second sintering of the mixture III in an oxygen-containing atmosphere to obtain the single-crystal cathode material.

[0014] Under the action of said crushing, the size distribution B of single-crystal particles of the single-crystal cathode material 90 =(P 90 -P 10 ) / P 50 satisfies 0.9≦B 90 ≦1.4.

[0015] In the above formula, P 10 represents the particle size corresponding to the cumulative single-crystal particle size distribution of the sample when the cumulative percentage reaches 10% in the SEM image of the cathode material, P 50 represents the particle size corresponding to the cumulative single-crystal particle size distribution of the sample when the cumulative percentage reaches 50% in the SEM image of the cathode material, and P 90 represents the particle size corresponding to the cumulative single-crystal particle size distribution of the sample when the cumulative percentage reaches 90% in the SEM image of the cathode material.

[0016] Said first sintering comprises that the sintering temperature is T / °C, the time from 400°C to T in the temperature rising step is t1 / h, and the time from T to 400°C in the cooling step is t2 / h, wherein t2 satisfies [ln(T-400)] / t2≦1.

[0017] In a third aspect of the present invention, a lithium ion battery is provided, wherein the lithium ion battery comprises the above single-crystal cathode material. Effects of the Invention

[0018] As described above, the single-crystal cathode material, its manufacturing method, and sodium-ion battery proposed in this invention have the following beneficial effects.

[0019] In this invention, SEM is used to determine that the single-crystal cathode material has single-crystal granules with a specific particle size distribution B 90 =(P 90 -P 10 ) / P 50 Furthermore, it was discovered that the single-crystal cathode material has a suitable Young's modulus, resulting in a high pressure density and, in addition, the ability to withstand higher rolling pressure during battery manufacturing. This increases the volumetric energy density of lithium-ion batteries equipped with the cathode material, as well as providing a good circulation retention rate and low resistance.

[0020] In the method for manufacturing a cathode material according to the present invention, the initial sintered product is crushed, and the single-crystal granules of the single-crystal cathode material are suppressed to a specific particle size distribution, thereby enabling the single-crystal cathode material to have a high compressive density.

[0021] Furthermore, research has shown that the inventors discovered that by slowing down the cooling rate, the solid-phase reaction becomes more complete, the granules become more uniformly rounded, the Young's modulus increases, and residual stress within the granules decreases, thereby increasing the granule strength. The material granules can withstand higher rolling pressure during battery manufacturing, thereby increasing the volumetric energy density of lithium-ion batteries with positive electrode material.

[0022] Furthermore, the method for manufacturing the cathode material according to the present invention is simple and easy to industrialize. [Brief explanation of the drawing]

[0023] [Figure 1] Figure 1 is an SEM image of the single-crystal cathode material of Example 1. [Figure 2] This is an SEM image of the single-crystal cathode material of Example 6. [Figure 3] Figure 3 is an SEM image of the single-crystal cathode material of Example 1 after applying a pressure of 400 MPa. [Figure 4]Figure 4 shows an SEM image of the single-crystal cathode material of Comparative Example 1 after applying a pressure of 400 MPa. [Figure 5] Figure 5 shows an SEM image of the single-crystal cathode material of Comparative Example 2 after applying a pressure of 400 MPa. [Modes for carrying out the invention]

[0024] The endpoints and any values ​​within the ranges described herein are not limited to those ranges or values, and should be understood to include ranges or values ​​close to those ranges or values. In the case of numerical ranges, it may be possible to obtain one or more new numerical ranges by combining the endpoint values ​​of each range, or by combining the endpoint values ​​of each range with individual point values, or by combining individual point values, and these numerical ranges are deemed to be disclosed herein.

[0025] In the first embodiment of this invention, a single-crystal cathode material is proposed. The size distribution of single-crystal granules in the single-crystal cathode material is B. 90 =(P 90 -P 10 ) / P 50 0.9 ≤ B 90 It satisfies ≤ 1.4.

[0026] The above formula includes P 10 This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 10% of the positive electrode material in the SEM image, P 50 This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample in the SEM image of the cathode material where the percentage reached 50%, and P 90 This represents the particle size corresponding to the cumulative single-crystal granule size distribution of the sample in the SEM image of the cathode material, where the percentage reached 90%.

[0027] The Young's modulus E of the cathode material, measured using an atomic force microscope, satisfies the condition 100 GPa ≤ E ≤ 200 GPa.

[0028] The present invention aims to increase the volumetric energy density of a lithium-ion battery equipped with a cathode material by ensuring that the single-crystal cathode material has a specific granule size distribution, possesses high pressure density, and has a high Young's modulus, thereby enabling it to withstand higher rolling pressure during battery manufacturing.

[0029] Specifically, the narrower the size distribution of single crystal granules, the worse the grading function of the single crystal granules and the lower the pressure density. Conversely, the wider the size distribution, the better the grading function and the higher the pressure density. However, if the distribution is too wide, there will be many fine powders and large granules in the material, making it easy for the powder to fall off during battery circulation, which in turn leads to a rapid loss of circulation performance. By keeping the size distribution of single crystal granules within the above range, there is good grading function between large and small granules in the cathode material, resulting in a high pressure density for the cathode material.

[0030] In this invention, based on quantity, P 10 10% of the single crystal granule size of the cathode material is P 10 It indicates that it is less than P 50 50% of the single crystal granule size of the cathode material is P 50 It indicates that it is less than P 90 90% of the single crystal granule size of the cathode material is P 90 This indicates that it is less than [a certain value].

[0031] In this invention, 500 single-crystal granules are randomly selected from an SEM image of the above-mentioned cathode material, and the projected area of ​​the 500 single-crystal granules is measured and converted into a standard circle of equal area. Then, the average diameter, i.e., the granule size P of the single-crystal cathode material, is obtained. It is possible to randomly select 500 granules and obtain the size by cumulatively selecting multiple granules in the SEM field of view.

[0032] In this invention, Young's modulus E refers to the magnitude of the force required for deformation per unit of granules. The higher the measured value, the less the shape of the granules changes, meaning that the granule strength increases. In this invention, the positive electrode material has a high Young's modulus E, which makes the electrode pieces of the positive electrode material less likely to break during the rolling and compressing process, and allows the positive electrode material to have a higher compressive density.

[0033] In this invention, the Young's modulus E of the cathode material is measured using an atomic force microscope.

[0034] In this invention, the size distribution B of single crystal granules 90 =(P 90 -P 10 ) / P 50 0.9 ≤ B 90 The condition ≤ 1.4 is satisfied. For example, B 90 is a range of 0.9, 1, 1.1, 1.2, 1.3, 1.4, and any two values, preferably 1 ≤ B 90 The value is ≤ 1.3.

[0035] In this invention, the Young's modulus E of the positive electrode material, measured using an atomic force microscope, satisfies 100 GPa ≤ E ≤ 200 GPa. For example, the Young's modulus E is in the range of 100 GPa, 110 GPa, 120 GPa, 130 GPa, 140 GPa, 150 GPa, 160 GPa, 170 GPa, 180 GPa, 190 GPa, 200 GPa, and any two values, preferably 120 GPa ≤ E ≤ 200 GPa.

[0036] According to the present invention, P 50 1μm ≤ P 50 The size must be ≤2μm.

[0037] In this invention, research has shown that if the granule size is too small, there are many small granules, which lowers the pressure density and can cause problems in processing applications such as increased viscosity, gelling of the paste, and powder fallout during electrode piece circulation. Conversely, if the granule size is too large, the increased lithium ion transmission paths lead to a decrease in electrical performance, and defects are more likely to occur in the large granules, thereby lowering the granule strength. 50 By keeping the above range, the positive electrode material possesses high pressure density, electrical conductivity, and granular strength.

[0038] In this invention, B 90 If P remains unchanged, 50 The larger the value, the greater the difference in size between granules in the cathode material. 2 μm <P 50 In this case, the large granules are too large, increasing internal residual stress and lowering the overall Young's modulus, which may make the granules more prone to fracture under the same compressive action. 50 For particles smaller than 1 μm, the ability to differentiate between large and small granules is insufficient, resulting in a decrease in pressure density.

[0039] In this invention, the positive electrode material P 50 1μm ≤ P 50 The condition ≤ 2 μm is satisfied. For example, P 50 P is a range of 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2 μm, and any two values ​​between them, preferably 1.3 μm ≤ P 50 The size is ≤1.7 μm.

[0040] According to the present invention, the coverage X of the cathode material measured by SEM satisfies 5% ≤ X.

[0041] In this invention, by coating the surface of the positive electrode material, the contact between single crystal granules is improved, increasing the material's compressive density. In addition, the coating layer on the surface of the positive electrode material also improves the granular strength of the material. Furthermore, keeping the coating rate of the positive electrode material within the above range helps to improve the surface and interface, compensating for surface defects in the material, reducing resistance, and increasing the Young's modulus E and granular strength of the positive electrode material. However, if the coating rate is too high, the number of electron transmission interfaces increases, thereby increasing the resistance of the material.

[0042] In this invention, coverage X is defined as the total surface area of ​​the surface coating of the single crystal granules / the total surface area of ​​the single crystal granules, and the total surface area of ​​the surface coating of the single crystal granules and the total surface area of ​​the single crystal granules are measured by SEM images. Specifically, the total surface area of ​​the single crystal granules is the total projected area of ​​the coating on the surface of 100 single crystal granules measured randomly by SEM images, and the total surface area of ​​the surface coating of the single crystal granules is the total projected area of ​​100 corresponding single crystal granules measured randomly by SEM images, and the ratio of the two is the coverage.

[0043] In this invention, the coverage X of the cathode material measured by SEM satisfies 5% ≤ X. For example, X is in the range of 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, and any two values, preferably 5% ≤ X ≤ 30%.

[0044] According to the present invention, the residual stress of the cathode material measured by XRD is 0-0.2%.

[0045] In this invention, the low residual stress of the positive electrode material indicates that it has many internal defects and is less prone to rupture.

[0046] In this invention, the residual stress of the cathode material is calculated through fine-tuning after XRD testing.

[0047] In this invention, the residual stress of the cathode material measured by XRD is 0-0.2%. For example, the residual stress is 0%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, and a range between any two values, preferably 0.01-0.15%.

[0048] According to the present invention, the median particle size D of the cathode material measured by a particle size analyzer 50 For 2μm ≤ D 50 The condition ≤ 6 μm is satisfied. For example, D 50 This range is 2μm, 2.2μm, 2.4μm, 2.6μm, 2.8μm, 3μm, 3.2μm, 3.4μm, 4μm, 4.2μm, 4.4μm, 4.6μm, 4.8μm, 5μm, 5.2μm, 5.4μm, 5.6μm, 5.8μm, 6μm, and any two values ​​between them, preferably 3μm ≤ D 50 The size is ≤5μm.

[0049] According to the present invention, the particle size change rate ΔD of the cathode material was measured with a particle size analyzer after being subjected to a pressurized treatment of 400 MPa. 10 =D 10 -D' 10 △D 10 Satisfies ≤0.2μm. D 10 D' represents the particle size before pressurization. 10 This represents the particle size after pressurization.

[0050] In this invention, the low rate of particle size change of the positive electrode material after a specific pressurizing treatment indicates that the positive electrode material has high granular strength and is difficult to crush during battery manufacturing.

[0051] According to the present invention, the pressure density of the positive electrode material is 3.3-3.7 g / cm³. 3 That is the case.

[0052] In this invention, the positive electrode material has high pressure density and high granular strength, and as a result, the battery made therefrom has a high volumetric energy density.

[0053] According to the present invention, the single-crystal cathode material has the composition shown in formula I.

[0054] Li 1+a (Ni x Mn y Co z G b )M c O2(I)

[0055] In the formula, 0 ≤ a ≤ 0.2, 0 <b≦0.05、0<c≦0.05、0.4≦x<1、0<y<0.5、0≦z<0.5、

[0056] M is selected from at least one of B, Nb, Co, Mo, W, Si, Mg, and Al.

[0057] G is selected from at least one of Ta, Nb, Hf, Zr, Ti, Al, W, Y, Sb, Sr, and Si.

[0058] In this invention, excluding Li, the main elements distributed within the granules of the single-crystal cathode material are Ni, Co, Mn, and G, and the main element distributed on the surface of the granules of the single-crystal cathode material is M.

[0059] In this invention, the metallic element M in the positive electrode material is the main metallic element in the coating, and the coating contains lithium oxide and / or oxide of element M, and further contains at least one of Ni, Co, Mn, and G derived from the substrate.

[0060] In one embodiment of the present invention, M is different from G.

[0061] In one embodiment of the present invention, M is selected from at least one of Al, W, Nb, B, and Mg.

[0062] In one embodiment of the present invention, M is selected from at least one of Al, W, B, and Mg.

[0063] In one embodiment of the present invention, G is selected from at least one of Ta, Nb, Hf, Zr, Ti, Al, W and Y.

[0064] In a preferred embodiment of the present invention, G satisfies E G-O ≧500kJ / mol, where E G-O is the G-O binding energy.

[0065] In the present invention, when selecting a G element having a high G-O binding energy after binding to oxygen for a positive electrode material, G will enter the crystal and participate in the crystal lattice structure, which further increases the Young's modulus of the positive electrode material. More preferably, G is selected from at least one of Ta, Nb, Hf, Zr and Ti.

[0066] In one specific embodiment of the present invention, in Formula I, a is 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.12, 0.14, 0.16, 0.18, 0.2, and a range between any two of the foregoing values, preferably 0≦a≦0.1. b is 0.01, 0.02, 0.03, 0.04, 0.05, and a range between any two of the foregoing values, preferably 0<b≦0.03. c is 0.01, 0.02, 0.03, 0.04, 0.05, and a range between any two of the foregoing values, preferably 0<c≦0.03.

[0067] In a second aspect of the present invention, a method for producing a single-crystal positive electrode material is provided. The production method comprises the following steps:

[0068] S1, mixing a nickel-cobalt-manganese precursor and a lithium source with an optional G element-containing additive to obtain a mixture I.

[0069] S2, subjecting mixture I to first sintering in an oxygen-containing atmosphere, and crushing to obtain a semi-finished product II of the single-crystal positive electrode material.

[0070] A semi-finished product II of S3 single-crystal cathode material is mixed with a coating agent containing a selectable element M to obtain mixture III.

[0071] S4. Mixture III is sintered a second time in an oxygen-containing atmosphere to obtain a single-crystal cathode material.

[0072] Under the aforementioned grinding action, the size distribution B of the single crystal granules of the single crystal cathode material 90 =(P 90 -P 10 ) / P 50 However, 0.9 ≤ B 90 It satisfies ≤ 1.4.

[0073] The above formula includes P 10 This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 10% of the positive electrode material in the SEM image, P 50 This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample in the SEM image of the cathode material where the percentage reached 50%, and P 90 This represents the particle size corresponding to the cumulative single-crystal granule size distribution of the sample in the SEM image of the cathode material, where the percentage reached 90%.

[0074] The initial sintering process includes a sintering temperature of T / °C, a heating step from 400°C to T of t1 / h, and a cooling step from T to 400°C of t2 / h, where t2 satisfies [ln(T-400)] / t2≦1.

[0075] In this invention, the single-crystal cathode material is made to have a high compressive density by crushing the product after the initial sintering, suppressing the single-crystal granules of the single-crystal cathode material to a specific particle size distribution, and controlling the cooling time during the initial sintering, thereby increasing the volumetric energy density of the lithium-ion battery equipped with the cathode material.

[0076] Specifically, by controlling the time of the cooling step during the first sintering within the above range, the cooling rate in the cooling step can be reduced. According to research, the inventors found that by reducing and slowly decreasing the cooling rate, the solid-phase reaction becomes more complete, the granules are more uniformly rounded, the Young's modulus increases, the residual stress inside the granules is reduced, and the granule strength is improved. This ensures that the material granules can withstand higher rolling pressure during battery manufacturing, and the positive electrode granules will not be damaged when manufacturing lithium-ion batteries with high volumetric energy density.

[0077] In the present invention, unless otherwise specified for crushing equipment and / or conditions, the size distribution B of single-crystal granules of the single-crystal positive electrode material 90 only needs to satisfy the limitations of the present invention.

[0078] In the present invention, t2 satisfies [ln(T-400)] / t2≤1. For example, t2 can be 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, and a range between any two of the above values; preferably, t2 satisfies [ln(T-400)] / t2≤0.9. In this relational expression, the unit of T is °C, the unit of t2 is h, the relational expression reflects the relationship between the sintering temperature T and the cooling time t2, and limits the cooling rate.

[0079] According to the present invention, 0 < t1 / t2 ≤ 1 is satisfied.

[0080] In the present invention, controlling the time t1 of the temperature rising step and the time t2 of the cooling step within the above ranges enables the material to have the characteristics of rapid temperature rise and slow cooling during the first sintering process, thereby increasing the Young's modulus of the prepared material granules and further reducing the residual stress inside the granules.

[0081] In the present invention, 0 < t1 / t2 ≤ 1; for example, t1 / t2 can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and a range between any two of the above values; preferably, 0.1 ≤ t1 / t2 ≤ 0.8 is satisfied.

[0082] According to the present invention, the condition 800℃ ≤ T ≤ 1000℃ is satisfied.

[0083] In this invention, by suppressing the sintering temperature T of the initial sintering, the granule size P 50 This makes it possible to suppress the above conditions, and when the above range is met, the resulting granule size becomes appropriate. If the temperature is too high, the granule size increases and the volume decreases. Furthermore, if the temperature is too low, the granule size decreases and circulation deteriorates.

[0084] In the present invention, the sintering temperature T of the initial sintering satisfies 800°C ≤ T ≤ 1000°C, and is, for example, 800°C, 810°C, 820°C, 830°C, 840°C, 850°C, 860°C, 870°C, 880°C, 890°C, 900°C, 910°C, 920°C, 930°C, 940°C, 950°C, 960°C, 970°C, 980°C, 990°C, 1000°C, and a range between any two values, preferably satisfying 850°C ≤ T ≤ 970°C.

[0085] In accordance with the present invention, in step S1, the G-element-containing additive is selected from at least one of an oxide of G, a hydroxide of G, and a carbonate of G.

[0086] According to the present invention, element G is selected from at least one of Ta, Nb, Hf, Zr, Ti, Al, W, Y, Sb, Sr, and Si.

[0087] In one specific embodiment of the present invention, G is selected from at least one of Ta, Nb, Hf, Zr, Ti, Al, W, and Y.

[0088] According to the present invention, G is E G-O Satisfying ≥ 500 kJ / mol, E G-O This is the GO bond energy.

[0089] In the present invention, when a compound of element G having high G-O binding energy after binding to oxygen is selected as an additive, G enters the interior of the crystal and participates in the crystal lattice structure, which further increases the Young's modulus of the positive electrode material. More preferably, G is selected from at least one of Ta, Nb, Hf, Zr and Ti.

[0090] According to the present invention, the dosages of the nickel-cobalt-manganese precursor, the lithium source and the G-containing additive satisfy 1≤n(Li) / [n(Ni)+n(Co)+n(Mn)]≤1.2 and 0<n(G) / [n(Ni)+n(Co)+n(Mn)]≤0.05.

[0091] Further, the dosages of the nickel-cobalt-manganese precursor, the lithium source and the G-containing additive satisfy 1≤n(Li) / [n(Ni)+n(Co)+n(Mn)]≤1.1 and 0<n(G) / [n(Ni)+n(Co)+n(Mn)]≤0.03.

[0092] In the present invention, the nickel-cobalt-manganese precursor is selected from nickel-cobalt-manganese oxide and / or nickel-cobalt-manganese hydroxide.

[0093] In the present invention, unless otherwise specified for the lithium source, lithium sources commonly used in the art such as lithium carbonate and lithium hydroxide can be used.

[0094] According to the present invention, the element M is selected from at least one of B, Nb, Co, Mo, W, Si, Mg and Al.

[0095] In one specific embodiment of the present invention, element M is different from element G.

[0096] In one specific embodiment of the present invention, element M is selected from at least one of Al, W, B and Mg.

[0097] In the present invention, as long as the coating agent can provide the element M, it is acceptable unless otherwise specifically specified. For example, oxides, hydroxides, carbonates, etc. containing the element M.

[0098] According to the present invention, the dosage of the semi-finished product II of the single-crystal positive electrode material and the element M-containing coating agent satisfies 0 < n(M) / [n(Ni)+n(Co)+n(Mn)] ≦ 0.05.

[0099] Further, the dosage of the semi-finished product II of the single-crystal positive electrode material and the element M-containing coating agent satisfies 0 < n(M) / [n(Ni)+n(Co)+n(Mn)] ≦ 0.03.

[0100] Further, the conditions for the second sintering include that the sintering temperature is 400-750°C and the sintering time is 6-10 h.

[0101] In the present invention, the oxygen-containing atmosphere is oxygen and / or air.

[0102] In the present invention, unless otherwise specifically specified for the crushing equipment, it is possible to use equipment commonly used in the art that is capable of crushing. For example, one or more of flour mills, jaw crushers, roll pairs, colloid mills, mechanical grinding mills and jet mills.

[0103] In the present invention, the method also comprises crushing and sieving the product after the second sintering.

[0104] In a third aspect of the present invention, a lithium ion battery is proposed, wherein the lithium ion battery comprises the above single-crystal positive electrode material.

[0105] Next, the present invention will be described in detail with reference to examples. In the following examples and comparative examples, the raw materials are commercially available products.

Examples

[0106] Example 1 1) Preparation of semi-finished product of single-crystal positive electrode material Using a high-performance mixer, nickel-cobalt-manganese hydroxide precursor (Ni 0.6 Co 0.2 Mn 0.2 )(OH)2 is uniformly mixed with lithium carbonate and the additive ZrO2 according to the ratio of [n(Ni)+n(Co)+n(Mn)]:n(Li):n(Zr)=1:1.04:0.002. Then, under an oxygen-containing atmosphere, the temperature is raised to 970°C over a time period t1=6h from 400°C to 970°C, held at the temperature for 10 hours, and then cooled over a time period of 8h from 970°C to 400°C. The mixture is sintered according to this process. After discharging the sintered raw material, the sintered raw material is crushed with a jet mill to obtain a semi-finished product of single-crystal cathode material.

[0107] 2) Preparation of single-crystal cathode material product Using a high-performance mixer, the above-mentioned semi-finished single-crystal cathode material is uniformly mixed with the coating agent WO3 according to the ratio of [n(Ni)+n(Co)+n(Mn)]:n(M)=1:0.01. Then, under an air atmosphere, the temperature is raised to 500°C and held for 8 hours. The mixture is sintered according to this process. After discharging the sintered raw material, the sintered raw material is crushed with a colloid mill to obtain the single-crystal cathode material product. D 50 is 3.8 μm.

[0108] Example 2 Except that the sintering temperature in step 1 is changed to 940°C, other process parameters are exactly the same as those in Example 1, as shown in Table 2.

[0109] Example 3 Except that in step 1), the composition of the precursor is changed to (Ni 0.8 Co 0.1 Mn 0.1 )(OH)2, the lithium source is changed to lithium hydroxide, the addition amount is set as [n(Ni)+n(Co)+n(Mn)]:n(Li):n(Zr)=1:1.03:0.002, the sintering temperature is changed to 890°C, and

[0110] Except for replacing WO3 with Co(OH)2 in step 2) and raising the sintering temperature to 700°C, all other process parameters are exactly the same as in Example 1, as shown in Table 2.

[0111] Example 4 Except for changing the ratio of the semi-finished crystalline cathode material to the coating agent WO3 in Step 2) to [n(Ni)+n(Co)+n(Mn)]:n(M)=1:0.04, all other process parameters are exactly the same as in Example 1, as shown in Table 2.

[0112] Example 5 Except for changing the sintering temperature to 1050°C in Step 1), all other process parameters are exactly the same as in Example 1, as shown in Table 2.

[0113] Example 6 Except for step 2), in which the above cathode material semi-finished product is uniformly mixed with the coating agent WO3 using a high-performance mixer in a ratio of [n(Ni)+n(Co)+n(Mn)]:n(M)=1:0.0005, all other process parameters are exactly the same as in Example 1, as shown in Table 2.

[0114] Example 7 Except for replacing the additive with TiO2 in Step 1) and uniformly mixing the materials using a high-performance mixer in the ratio [n(Ni)+n(Co)+n(Mn)]:n(Li):n(Ti)=1:1.04:0.002, all other method parameters are exactly the same as in Example 1, as shown in Table 2.

[0115] Example 8 Except for the fact that in Step 1) the additives are replaced with Y2O3 and Al2O3, and the mixture is uniformly mixed using a high-performance mixer according to the ratio [n(Ni)+n(Co)+n(Mn)]:n(Li):n(Y):n(Al)=1:1.04:0.001:0.001, the sintering temperature is set to 960°C, t1 is set to 5h, and t2 is set to 7h,

[0116] Table 2 shows the other method parameters, except that in Step 2) the coating agent is replaced with B2O3, and the mixture is uniformly mixed using a high-performance mixer according to the ratio [n(Ni)+n(Co)+n(Mn)]:n(M)=1:0.005, and the sintering temperature is set to 250°C.

[0117] Example 9 Except for replacing the additive with Al2O3 in Step 1), and uniformly mixing the materials using a high-performance mixer according to the ratio [n(Ni)+n(Co)+n(Mn)]:n(Li):n(Al)=1:1.04:0.002, setting the sintering temperature to 940°C, setting t1 to 5h, and setting t2 to 9h,

[0118] Table 2 shows the other method parameters, except that in Step 2) the coating agent is replaced with B2O3 and WO3, and the mixture is uniformly mixed using a high-performance mixer according to the ratio [n(Ni)+n(Co)+n(Mn)]:n(B):n(W)=1:0.001:0.001, and the sintering temperature is set to 400°C.

[0119] Comparative Example 1 Step 1) Increase the crushing strength during crushing to create granule distribution B 90 Except for obtaining a product with a coefficient of 0.83, all other process parameters are exactly the same as in Example 1, as shown in Table 2.

[0120] Comparative Example 2 Step 1) Except for the fact that the time period t2 for the temperature to drop to 400℃ is 4 hours, all other construction method parameters are exactly the same as in Example 1, as shown in Table 2.

[0121] [Table 1]

[0122] [Table 2-1]

[0123] [Table 2-2]

[0124] [Table 2-3]

[0125] Tests and Equipment (1) Particle size D 10 , D 50 , D' 10 are measured using a Hydro 2000mu model particle size analyzer manufactured by Malvern.

[0126] (2) Tap density (hereinafter referred to as PD) is measured using a BT-30 model tap density tester manufactured by Baxter.

[0127] For the pressure test, a pressure test is performed using a Carver tap density meter. The test method is as follows. First, accurately weigh 3 g of a sample, place it into a compaction mold, attach a hammering plate and a cylindrical piston, then gradually pressurize to 7.5 t, hold the pressure for 10 minutes, maintain a constant pressure for 30 seconds, and the sample after the pressure test is D' 10 obtained.

[0128] (3) For the electron microscope test, measurement is performed using an S-4800 model scanning electron microscope (SEM) manufactured by Hitachi.

[0129] Measurement software is used to count the projected area of each single-crystal granule in the electron microscope and calculate the granule size thereof. The specific method is as follows: 500 single-crystal granules are randomly selected from an SEM image, the projected areas of the 500 single-crystal granules are measured and converted into standard circles of equal area, then the average diameter, that is, the granule size P of the single-crystal positive electrode material, is obtained. Statistical calculation is performed on the granule sizes of the above 500 single-crystal granules. The particle size P corresponding to the cumulative single-crystal granule size distribution of the sample reaching 10% by percentage 10 is obtained, and the particle size P corresponding to the cumulative single-crystal granule size distribution of the sample reaching 50% by percentage 50The particle size P corresponding to the cumulative single crystal granule size distribution of the sample, which reached 90% of the percentage obtained, was obtained. 90 We obtained the size distribution of single crystal granules and determined B 90 =(P 90 -P 10 ) / P 50 It is defined as follows: 500 granules may be randomly selected and acquired cumulatively in multiple locations within the SEM field of view.

[0130] Using measurement software, the total projected area and the total projected area of ​​surface coatings for 100 single crystal granules are statistically analyzed, and the coverage rate X is defined as the total surface area of ​​the surface coatings of the single crystal granules divided by the total surface area of ​​the single crystal granules.

[0131] The crack state in the cross-section is observed using SEM images of the cross-section of the cathode material.

[0132] (4) The Young's modulus is observed using a Bruker atomic force microscope and measured using a gilent Nano Indenter G200 from Keysight. Ten granules are randomly selected from each lot of the sample, tested, and the average value is calculated to obtain the Young's modulus E of the material.

[0133] (5) Residual stress is measured using the Smartlab 9KW rotating target diffractometer manufactured by RIKEN, and the residual stress is calculated through fine adjustment using XRD.

[0134] (6) Battery manufacturing and electrical characteristics testing

[0135] In the above examples and comparative examples, the electrochemical performance of the positive electrode material is tested using a CR2025 button cell battery. The manufacturing process is as follows:

[0136] For the manufacture of the electrode pieces, the positive electrode material, conductive carbon black, and polyvinylidene fluoride (PVDF) are completely mixed with an appropriate amount of N-methylpyrrolidone (NMP) in a mass ratio of 95:3:2 to form a uniform paste (solid content of 60% at 25°C). This slurry is applied to aluminum foil, dried at 120°C for 12 hours, and then press-molded under a pressure of 100 MPa to produce positive electrode pieces with a diameter of 15.8 mm and a thickness of 3.2 mm. The load capacity of the positive electrode material is 15.5 mg / cm2. The positive electrode pieces, diaphragm, negative electrode pieces, and electrolyte are assembled into a CR2025 button-type sodium-ion battery and left to stand for 6 hours in an argon-filled glove box with a moisture and oxygen content of less than 5 ppm. A metallic sodium sheet with a diameter of 15.8 mm and a thickness of 1 mm is used as the negative electrode piece, a polypropylene microporous membrane (Celgard 2325) with a thickness of 25 μm is used as the diaphragm, and a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in equal proportions to 1 mol / L NaPF6 is used as the electrolyte.

[0137] For capacity testing, the electrochemical performance of CR2025 button cell batteries was tested using the Shenzhen Xinweier battery testing system, with a charge / discharge current density of 100 mA / g at 0.1C. The charge / discharge voltage range was limited to 3.0-4.45V, and the charge / discharge test was performed at 0.1C on the button cell batteries at room temperature to evaluate the charge / discharge ratio capacity of the positive electrode material. Example 3 applies to high-nickel materials, and the test voltage range is 3.0-4.35V.

[0138] For the high-temperature cycle performance test, the charge / discharge voltage range was limited to 3.0-4.45V in the experimental and comparative examples. Under constant temperature conditions of 60°C, two charge / discharge cycles were performed on a button-type battery at 0.1C, followed by 80 charge / discharge cycles at 1C, and the high-temperature cycle capacity retention rate of the positive electrode material was evaluated.

[0139] For resistance testing, before testing the battery under high-temperature circulation, the resistance at 50% SOC after full charge is measured to obtain the initial resistance. After testing the battery under high-temperature circulation, the resistance at 50% SOC after full charge is measured to obtain the final resistance. The resistance increase rate (%) is defined as (final resistance - initial resistance) / initial resistance × 100%.

[0140] [Table 3-1]

[0141] [Table 3-2]

[0142] According to Table 3, the single-crystal cathode material according to the present invention has a specific granule size distribution B 90 It has a high Young's modulus, which gives the assembled button-type battery high capacity, excellent high-temperature circulation retention, and low resistance performance. In other words, by adjusting the conditions of the initial sintering according to the method of the present invention, residual stress inside the single crystal granules can be removed, and consequently the granular strength of the positive electrode material can be increased.

[0143] Conversely, in the single-crystal cathode material of Comparative Example 2, if the cooling rate of the initial sintering during the manufacturing process is too high, not only is it impossible to remove existing internal stresses, but the rapid cooling during the cooling process causes new stress deformation, ultimately leading to high residual stress and a low Young's modulus within the granules, i.e., a decrease in hardness. During battery manufacturing and circulation processes, the edges of the granule surface are crushed during the rolling and pressing process, making it easier for cracks to occur inside the granules, which impairs circulation and significantly increases the resistance of the circulated material.

[0144] In Comparative Example 1, based on experimental examples, the particle size distribution B was increased by improving the crushing strength of the initially sintered material. 90 Adjust the setting, and if the granule size is the same, then use B 90When the size decreases, it indicates that the grading function of the material granules is inferior, resulting in low compressive density. During manufacturing, high crushing strength damages the surface / internal structure of the granules, leading to high residual stress and low granule strength. Furthermore, greater crushing strength inevitably produces fine powder, which reduces the high-temperature circulation retention rate and increases resistance.

[0145] Furthermore, the particle size D of the cathode material before and after the pressure test. 10 Change in value △D 10 =D 10 -D' 10 By observing this, it can be seen that the granules of the positive electrode material after the pressure test are crushed, and the D before pressure 10 Compared to D' after pressure 10 They discovered that the value decreases, and that the lower the hardness of the material, the more easily it breaks, and △D 10 The value becomes larger. The comparative example has a smaller Young's modulus compared to the experimental example, making it easier to crush its granules, and △D 10 The change in value will also be large.

[0146] Figure 1 is an SEM image of the single-crystal cathode material of Example 1. The protrusions on the surface are coating granules, which play a role in improving the pressure density of the cathode material and can also distribute the force applied to the material granules, thereby increasing the granule strength. Figure 2 is an SEM image of the single-crystal cathode material of Example 6. Because the amount of coating agent added is small, there are almost no coating granules on the surface, resulting in a lower pressure density and inferior granule strength for Example 6.

[0147] Figures 3, 4, and 5 are SEM images after pressure testing was performed on the cathode materials of Example 1, Comparative Example 1, and Comparative Example 2, respectively. As shown in the figures, after pressure testing was performed on the cathode material granules of Example 1, there were almost no cracks in the single granules, while Comparative Examples 1 and 2 had varying degrees of cracking. This is consistent with the Young's modulus test and proves that the granular strength of the material is low.

[0148] The single crystal granules in Example 2 are slightly smaller in size and have a shorter ion transmission distance, resulting in a slight increase in battery capacity.

[0149] In Example 3, the Ni content was high, resulting in a higher battery capacity compared to the Example with a lower Ni content under the same test conditions.

[0150] In Example 5, the temperature is too high, causing the granule size to exceed the upper limit. The combination of extremely high temperature and large granule size may reduce the granule strength of the material, making it prone to crushing, resulting in a low measurement of Young's modulus. Furthermore, the large granule size reduces the lithium-ion transmission capacity, and electrical performance data such as capacitance and resistance are also inferior.

[0151] Compared to Example 1, Example 4 contains more additives, resulting in a relatively higher coverage rate. While a large amount of coating agent provides greater granular strength (Young's modulus), it also increases the number of interfaces through which electrons are transferred, thus raising the initial resistance value and the rate of increase.

[0152] Preferred embodiments of the present invention have been described in detail above, but are not limited thereto. Within the scope of the technical concept of the present invention, it is possible to perform simple modifications to the technical means of the present invention and combine various technical features in other suitable ways, and such simple modifications and combinations should also be considered as being disclosed in the present invention and all fall within the scope of protection of the present invention. (Note) This disclosure includes the following aspects: Item 1: A single-crystal cathode material, wherein the size distribution B of the single-crystal granules of the single-crystal cathode material 90 =(P 90 -P 10 ) / P 50 However, 0.9 ≤ B 90 Satisfying ≤ 1.4, Here, P 10 This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 10% of the SEM image of the cathode material, P 50 This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 50% in the SEM image of the cathode material, P 90 This represents the particle size corresponding to the cumulative single-crystal granule size distribution of the sample that reached 90% in the SEM image of the cathode material. The Young's modulus E of the positive electrode material, as measured using an atomic force microscope, satisfies 100 GPa ≤ E ≤ 200 GPa. A single-crystal cathode material characterized by the following features. Item 2: 1≦B 90 ≤ 1.3, Preferably, 120 GPa ≤ E ≤ 200 GPa, Preferably, 1 μm ≤ P 50 ≤2μm, Preferably, 1.3 μm ≤ P 50 The size is ≤1.7μm. A single-crystal cathode material as described in item 1, characterized by the features described herein. Item 3: The coverage X of the positive electrode material, as measured by SEM, satisfies 5% ≤ X, and preferably 5% ≤ X ≤ 30%. Preferably, the residual stress of the positive electrode material measured by XRD is 0 to 0.2%. Preferably, the median particle size D of the positive electrode material is measured by a particle size analyzer. 50 However, 2μm≦D 50 Satisfying ≤6μm, Preferably, the particle size change rate ΔD of the positive electrode material is measured with a particle size analyzer after pressurization at 400 MPa. 10 =D 10 -D’ 10 However, △D 10 The condition ≤0.2μm is satisfied, where D 10 D' represents the particle size before pressurization. 10 This represents the particle size after pressurization. Preferably, the pressure density of the positive electrode material is 3.3-3.7 g / cm³. 3 That is, A single-crystal cathode material according to item 1 or 2, characterized by the above. Item 4: Having the composition shown in formula I, Li 1+a (Ni x Mn y Co z G b )M c O 2 Equation I Here, 0 ≤ a ≤ 0.2, 0 <b≦0.05、0<c≦0.05、0.4≦x<1、0<y<0.5、0≦z<0.5、 M is selected from at least one of B, Nb, Co, Mo, W, Si, Mg, and Al. G is selected from at least one of Ta, Nb, Hf, Zr, Ti, Al, W, Y, Sb, Sr, and Si. A single-crystal cathode material according to any one of items 1 to 3, characterized by the above. Item 5: The steps include: S1, mixing a nickel-cobalt-manganese precursor and a lithium source with a selectable G element-containing additive to obtain mixture I; S2, a step in which mixture I is initially sintered and crushed in an oxygen-containing atmosphere to obtain a semi-finished product II of single-crystal cathode material, S3 is a step of mixing a semi-finished single-crystal cathode material II with a coating agent containing a selectable element M to obtain a mixture III. S4 includes the step of sintering mixture III a second time in an oxygen-containing atmosphere to obtain a single-crystal cathode material. Size distribution B of single crystal granules of single crystal cathode material under the action of crushing described above. 90 =(P 90 -P 10 ) / P 50 However, 0.9 ≤ B 90 Satisfying ≤ 1.4, Here, P 10 This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 10% of the SEM image of the cathode material, P 50 This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 50% in the SEM image of the cathode material, P 90 This represents the particle size corresponding to the cumulative single-crystal granule size distribution of the sample that reached 90% in the SEM image of the cathode material. The aforementioned initial sintering has a sintering temperature of T / °C, and the time from 400°C to T in the heating step is t 1 / h is the time from T to 400°C in the cooling step t 2 This includes the fact that / h, where t 2 ga [ln(T-400)] / t 2 Satisfying ≤ 1, A method for manufacturing a single-crystal cathode material according to any one of items 1 to 4, characterized by the above. Item 6: 0<t 1 / t 2 The manufacturing method according to item 5, characterized in that ≤ 1 and / or 800℃ ≤ T ≤ 1000℃. Item 7: In step S1, the G-element-containing additive is selected from at least one of an oxide of G, a hydroxide of G, and a carbonate of G. Preferably, the G element is selected from at least one of Ta, Nb, Hf, Zr, Ti, Al, W, Y, Sb, Sr, and Si. Preferably, G is E G-O Satisfying ≥ 500 kJ / mol, E G-O This is the GO bond energy, Preferably, the amounts of the nickel-cobalt-manganese precursor, the lithium source, and the G-containing additive are such that 1 ≤ n(Li) / [n(Ni) + n(Co) + n(Mn)] ≤ 1.2 and 0 ≤ n(G) / [n(Ni) + n(Co) + n(Mn)] ≤ 0.05. The manufacturing method described in item 5 or 6, characterized by the above. Item 8: The aforementioned M element is selected from at least one of B, Nb, Co, Mo, W, Si, Mg, and Al. Preferably, the amounts of the semi-finished product II of the single-crystal cathode material and the coating agent containing element M are 0 ≤ n(M) / [n(Ni) + n(Co) + n(Mn)] ≤ 0.05. A manufacturing method according to any one of items 5 to 7, characterized by the above. Item 9: The conditions for the second sintering include a sintering temperature of 300 to 800°C and a sintering time of 4 to 12 hours. A manufacturing method according to any one of items 5 to 8, characterized by the above. Item 10: A lithium-ion battery characterized by containing a single-crystal cathode material described in any one of items 1 to 4.

Claims

1. A single-crystal cathode material, wherein the size distribution B of the single-crystal granules of the single-crystal cathode material. ９０ = (P ９０ -P １０ ) / P ５０ However, 0.9 ≤ B ９０ Satisfying ≤ 1.4, Here, P １０ This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 10% in the SEM image of the cathode material, P ５０ This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 50% in the SEM image of the cathode material, P ９０ This represents the particle size corresponding to the cumulative single-crystal granule size distribution of the sample that reached 90% in the SEM image of the cathode material. The Young's modulus E of the positive electrode material, as measured using an atomic force microscope, satisfies 100 GPa ≤ E ≤ 165 GPa. A single-crystal cathode material characterized by the following features.

2. 1 ≦ B ９０ ≦ 1.3, 1 μm ≤ P ５０ The size is ≤2 μm. The single-crystal cathode material according to feature 1.

3. The coverage X of the positive electrode material measured by SEM satisfies 5% ≤ X, The residual stress of the positive electrode material measured by XRD is 0 to 0.2%. The median particle size D of the positive electrode material measured by a particle size analyzer ５０ However, 2 μm ≤ D ５０ Satisfying ≤ 6 μm, The particle size change rate ΔD of the positive electrode material, measured with a particle size analyzer after pressurization at 400 MPa. １０ = D １０ -D' １０ However, △D １０ The condition ≤ 0.2 μm is satisfied, where D １０ D' represents the particle size before pressurization. １０ This represents the particle size after pressurization. The pressure density of the aforementioned positive electrode material is 3.3 to 3.7 g / cm³. ３ That is, The single-crystal cathode material according to feature 1.

4. Having the composition shown in formula I, Li １＋ａ (Ni ｘ Mn ｙ Co ｚ G ｂ )M ｃ O ２ Formula I Here, 0 ≤ a ≤ 0.2, 0 < b ≤ 0.05, 0 < c ≤ 0.05, 0.4 ≤ x < 1, 0 < y < 0.5, 0 ≤ z < 0.5, M is selected from at least one of B, Nb, Co, Mo, W, Si, Mg, and Al. G is selected from at least one of Ta, Nb, Hf, Zr, Ti, Al, W, Y, Sb, Sr, and Si. The single-crystal cathode material according to feature 1.

5. S1, a step of mixing nickel-cobalt-manganese precursor and lithium source with an additive containing element G to obtain mixture I, S2, a step of first sintering mixture I in an oxygen-containing atmosphere and crushing it to obtain a semi-finished product II of single-crystal cathode material, S3, a step of mixing the semi-finished single-crystal cathode material II with an element M-containing coating agent to obtain mixture III, S4 includes the step of sintering mixture III a second time in an oxygen-containing atmosphere to obtain a single-crystal cathode material. Size distribution B of single crystal granules of single crystal cathode material under the action of crushing. ９０ = (P ９０ -P １０ ) / P ５０ However, 0.9 ≤ B ９０ Satisfying ≤ 1.4, Here, P １０ This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 10% in the SEM image of the cathode material, P ５０ This represents the particle size corresponding to the cumulative single crystal granule size distribution of the sample that reached 50% in the SEM image of the cathode material, P ９０ This represents the particle size corresponding to the cumulative single-crystal granule size distribution of the sample that reached 90% in the SEM image of the cathode material. The aforementioned initial sintering has a sintering temperature of T / °C, and the time from 400°C to T in the heating step is t １ / h, and the time from T to 400°C in the cooling step is t ２ This includes the fact that / h, where t ２ ga [ln(T-400)] / t ２ Satisfying ≤ 1, A method for producing a single-crystal cathode material according to feature 1.

6. 0 < t １ / t ２ The manufacturing method according to claim 5, characterized in that ≤ 1 and / or 800°C ≤ T ≤ 1000°C.

7. In step S1, the G-element-containing additive is selected from at least one of an oxide of G, a hydroxide of G, and a carbonate of G. Element G is selected from at least one of Ta, Nb, Hf, Zr, Ti, Al, W, Y, Sb, Sr, and Si. G is E Ｇ－Ｏ Satisfying ≥ 500 kJ / mol, E Ｇ－Ｏ This is the G-O bond energy, The doses of the nickel-cobalt-manganese precursor, the lithium source, and the G element-containing additive are such that 1 ≤ n(Li) / [n(Ni) + n(Co) + n(Mn)] ≤ 1.2 and 0 < n(G) / [n(Ni) + n(Co) + n(Mn)] ≤ 0.

05. The manufacturing method according to claim 5, characterized in that it

8. The aforementioned M element is selected from at least one of B, Nb, Co, Mo, W, Si, Mg, and Al. The amounts of the semi-finished product II of the single-crystal cathode material and the coating agent containing element M are 0 < n(M) / [n(Ni) + n(Co) + n(Mn)] ≤ 0.

05. The manufacturing method according to claim 5, characterized in that it

9. The conditions for the second sintering include a sintering temperature of 300 to 800°C and a sintering time of 4 to 12 hours. The manufacturing method according to any one of claims 5 to 8, characterized by...

10. A lithium-ion battery characterized by containing the single-crystal cathode material described in any one of claims 1 to 4.

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