Modified ternary materials, their preparation methods and applications, and lithium-ion batteries

Abstract

This invention relates to a modified ternary material, its preparation method and application, and lithium-ion batteries. The modified ternary material includes a core layer and a shell layer disposed on the surface of the core layer. The core layer comprises multiple primary particles arranged radially in a radial pattern. The composition of the core layer includes the metallic element M. 1 Doped lithium nickel cobalt manganese oxide; the shell is a single-crystal material, and the shell composition includes the metallic element M. 1 and metallic element M 2 Co-doped lithium nickel cobalt manganese oxide, or shell components including the metal element M 1 Metal element M 2 and metallic element M 3 Co-doped lithium nickel cobalt manganese oxide, metal element M 2 The ternary material is selected from at least two of K, Na, Ba, Bi, Ca, Sr, Mg, Mo, B, Ce, and Sb. This modified ternary material exhibits low gas production, high initial discharge specific capacity, and good cycle performance.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion batteries, and in particular to a modified ternary material, its preparation method and application, and lithium-ion batteries. Background Technology

[0002] Lithium-ion batteries are widely used in electronics, electric vehicles, and aerospace due to their high energy density, good cycle performance, lack of memory effect, and environmental friendliness. However, traditional lithium-ion battery cathode materials suffer from high impedance, resulting in low initial discharge specific capacity and affecting cycle performance.

[0003] Therefore, it is of great significance to provide a lithium-ion battery cathode material with low impedance, high initial discharge specific capacity, and good cycle performance. Summary of the Invention

[0004] Based on this, the present invention provides a modified ternary material with low impedance, high initial discharge specific capacity or good cycle performance, its preparation method and application, and a lithium-ion battery.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows.

[0006] A modified ternary material includes a core layer and a shell layer disposed on the surface of the core layer; the core layer comprises a plurality of primary particles arranged radially in a radial pattern, and the composition of the core layer includes the metallic element M. 1 Doped lithium nickel cobalt manganese oxide; the shell is a single-crystal material, and the composition of the shell includes the metallic element M. 1 and metallic element M 2 Co-doped lithium nickel cobalt manganese oxide, or the shell composition including the metal element M. 1 Metal element M 2 and metallic element M 3 Co-doped lithium nickel cobalt manganese oxide;

[0007] The metallic element M 1 Selected from at least one of Al, B, Ba, Bi, Ca, Cr, Ce, Co, Er, Ga, Ge, Ho, K, La, Mg, Mo, Na, Nb, Pd, Si, Sb, Sr, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr, and Zn;

[0008] The metallic element M 2 At least two of the following are selected from K, Na, Ba, Bi, Ca, Sr, Mg, Mo, B, Ce, and Sb;

[0009] The metallic element M 3It is selected from at least one of Al, Cr, Co, Er, Ga, Ge, Ho, La, Nb, Pd, Si, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr and Zn.

[0010] In some embodiments, the modified ternary material has the chemical formula Li. 1+a [Ni x Co y Mn z M 1 b M 2 c M 3 d O2, where 0.5≤x<1, 0≤y≤0.3, 0≤z≤0.3, -0.1 <a<0.2,0<b<0.3,0<c<0.3,0≤d<0.2,x+y+z+b+c+d=1。

[0011] In some embodiments, the modified ternary material has 0.003 ≤ b < 0.3 and 0.005 ≤ c < 0.3.

[0012] In some embodiments, the core layer of the modified ternary material has porosity of 0.001% to 10%.

[0013] In some embodiments, in the modified ternary material, the width of the primary particles is 80nm to 200nm, and the ratio of the length to the width of the primary particles is ≥2.

[0014] In some embodiments, the modified ternary material further includes a coating layer disposed on the surface of the shell, the coating layer comprising a metallic element M. 4 The oxide of the metal element M 4 It is selected from at least one of Al, B, Ba, Bi, Ca, Cr, Ce, Co, Er, Ga, Ge, Ho, K, La, Mg, Mo, Na, Nb, Pd, Si, Sb, Sr, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr, and Zn.

[0015] In some embodiments, the thickness of the coating layer in the modified ternary material is 0.001 μm to 0.5 μm.

[0016] In some embodiments, the modified ternary material has a specific surface area of ​​0.8 m². 2 / g~2.0m 2 / g.

[0017] In some embodiments, the modified ternary material has a PD of 2.5 g / cm³. 3 ~3.3g / cm 3 .

[0018] In some embodiments, the modified ternary material has a D50 of 2 μm to 8 μm.

[0019] In some embodiments, the modified ternary material has an average particle size of 1.2 μm to 5.2 μm.

[0020] In some embodiments, in the modified ternary material, the ratio of the difference between the outer diameter of the shell and the outer diameter of the core to the outer diameter of the shell is (0.01 to 0.99):1.

[0021] This invention provides a method for preparing a modified ternary material, comprising the following steps:

[0022] Nickel-cobalt-manganese ternary material precursor, metal element M 1 The precursor and lithium source are mixed and subjected to a first sintering process to obtain a ternary material intermediate; and

[0023] The ternary material intermediate and the metal element M are combined 2 The precursor is mixed and subjected to a second sintering process, or the ternary material intermediate is mixed with the metallic element M. 2 Precursor and metallic element M 3 The precursors are mixed and then subjected to a second sintering process.

[0024] The nickel-cobalt-manganese ternary material precursor includes multiple primary particles, which are arranged radially in a radial pattern.

[0025] Metal element M 1 Selected from at least one of Al, B, Ba, Bi, Ca, Cr, Ce, Co, Er, Ga, Ge, Ho, K, La, Mg, Mo, Na, Nb, Pd, Si, Sb, Sr, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr, and Zn;

[0026] The metallic element M 2 At least two of the following are selected from K, Na, Ba, Bi, Ca, Sr, Mg, Mo, B, Ce, and Sb;

[0027] The metallic element M 3 It is selected from at least one of Al, Cr, Co, Er, Ga, Ge, Ho, La, Nb, Pd, Si, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr and Zn.

[0028] In some embodiments, the preparation method of the modified ternary material further includes the step of adding a lithium source in the second sintering process.

[0029] In some embodiments, in the preparation method of the modified ternary material, the temperature of the first sintering treatment is 600℃~1000℃.

[0030] In some embodiments, in the preparation method of the modified ternary material, the temperature of the second sintering treatment is 600℃~1000℃.

[0031] In some embodiments, the method for preparing the modified ternary material further includes combining the ternary material obtained from the second sintering treatment with the metallic element M. 4 The precursor mixture undergoes a third sintering process; the metal element M 4 It is selected from at least one of Al, B, Ba, Bi, Ca, Cr, Ce, Co, Er, Ga, Ge, Ho, K, La, Mg, Mo, Na, Nb, Pd, Si, Sb, Sr, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr, and Zn.

[0032] In some embodiments, the temperature of the third sintering treatment in the preparation method of the modified ternary material is 150°C to 750°C.

[0033] This invention provides the application of the modified ternary material described above or the modified ternary material prepared by the above preparation method in the preparation of lithium-ion batteries.

[0034] The present invention provides a lithium-ion battery, comprising a positive electrode, a separator, and a negative electrode, wherein the positive electrode and the negative electrode are disposed on both sides of the separator, and the positive electrode comprises the modified ternary material described above or the modified ternary material prepared by the preparation method described above.

[0035] Compared with the prior art, the modified ternary material of the present invention has the following beneficial effects:

[0036] The aforementioned modified ternary material has a specific type of metal element M doped into the lithium nickel cobalt manganese oxide core layer. 1 This effectively improves the stability of the radially arranged primary particles in the core layer of the modified ternary material; the radially arranged particles inside the core layer can uniformly contract and expand during charge-discharge cycles, exhibiting strong resistance to microcracks; and the lithium nickel cobalt manganese oxide in the shell layer is doped with the metal element M. 1 and various metallic elements M 2 Or doped with metallic element M 1 Multiple metallic elements M 2 and metallic element M 3 M of various specific types of metallic elements2 The synergistic effect between them further interacts with specific types of metallic elements M. 1 and / or metallic element M 3 This process effectively promotes the formation of a single-crystal shell and further enhances the stability of the radially arranged core layer in the modified ternary material. The combined effect of the radially arranged core layer and the single-crystal shell layer effectively reduces the transport resistance and distance of lithium ions from the bulk phase to the surface, resulting in lower impedance of the modified ternary material. Consequently, the modified ternary material exhibits lower gas production, higher initial discharge specific capacity, and better cycle performance. Attached Figure Description

[0037] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 A schematic diagram of the structure of a modified ternary material provided in one embodiment;

[0039] Figure 2 A schematic diagram of the structure of the modified ternary material provided for another embodiment;

[0040] Figure 3 This is a schematic diagram of the structure of a nickel-cobalt-manganese ternary material precursor in one embodiment;

[0041] Figure 4 This is a schematic diagram of the structure of a ternary material intermediate according to one embodiment;

[0042] Figure 5 This is a cross-sectional view of the bulk particles obtained in Example 1;

[0043] Figure 6 Here is a scanning electron microscope image of the bulk particles prepared in Example 1;

[0044] Figure 7 This is a cross-sectional view of the bulk particles prepared in Comparative Example 1.

[0045] Figure 8 This is a schematic diagram of the cross-sectional structure of the ternary material prepared in Comparative Example 1;

[0046] Figure 9 The image shows a scanning electron microscope (SEM) image of the bulk particles prepared in Comparative Example 2.

[0047] Figure 10 The image shows a scanning electron microscope (SEM) image of the bulk particles prepared in Comparative Example 3.

[0048] Figure 11 The image shows a scanning electron microscope (SEM) image of the bulk particles prepared in Comparative Example 4.

[0049] Figure 12 The diagram shows the cross-sectional structure of the ternary materials prepared in Comparative Examples 2-4. Detailed Implementation

[0050] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. It should be understood that these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0052] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0053] The weights of the relevant components mentioned in the embodiments of this invention can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this invention is within the scope disclosed in the embodiments of this invention. Specifically, the weights mentioned in the embodiments of this invention can be well-known units of mass in the chemical industry, such as μg, mg, g, and kg.

[0054] Please refer to Figure 1 One embodiment of the present invention provides a modified ternary material 100, which includes a core layer 110 and a shell layer 120 disposed on the surface of the core layer 110; the core layer 110 includes a plurality of primary particles arranged radially in a radial pattern, and the composition of the core layer 110 includes the metallic element M. 1 Doped lithium nickel cobalt manganese oxide; shell 120 is a single crystal material, and the composition of shell 120 includes the metal element M. 1 and metallic element M 2 Co-doped lithium nickel cobalt manganese oxide, or the composition of shell 120 including the metal element M1 Metal element M 2 and metallic element M 3 Co-doped lithium nickel cobalt manganese oxide;

[0055] Metal element M 1 Selected from at least one of Al, B, Ba, Bi, Ca, Cr, Ce, Co, Er, Ga, Ge, Ho, K, La, Mg, Mo, Na, Nb, Pd, Si, Sb, Sr, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr, and Zn;

[0056] Metal element M 2 At least two of the following are selected from K, Na, Ba, Bi, Ca, Sr, Mg, Mo, B, Ce, and Sb;

[0057] Metal element M 3 It is selected from at least one of Al, Cr, Co, Er, Ga, Ge, Ho, La, Nb, Pd, Si, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr and Zn.

[0058] The aforementioned modified ternary material has a specific type of metal element M doped into the lithium nickel cobalt manganese oxide core layer. 1 This effectively improves the stability of the radially arranged primary particles in the core layer of the modified ternary material; the radially arranged particles inside the core layer can uniformly contract and expand during charge-discharge cycles, exhibiting strong resistance to microcracks; and the lithium nickel cobalt manganese oxide in the shell layer is doped with the metal element M. 1 and various metallic elements M 2 Or doped with metallic element M 1 Multiple metallic elements M 2 and metallic element M 3 M of various specific types of metallic elements 2 The synergistic effect between them further interacts with specific types of metallic elements M. 1 and / or metallic element M 3 This process effectively promotes the formation of a single-crystal shell and further enhances the stability of the radially arranged core layer in the modified ternary material. The combined effect of the radially arranged core layer and the single-crystal shell layer effectively reduces the transport resistance and distance of lithium ions from the bulk phase to the surface, resulting in lower impedance of the modified ternary material. Consequently, the modified ternary material exhibits lower gas production, higher initial discharge specific capacity, and better cycle performance.

[0059] It can be understood that the aforementioned modified ternary material has a core-shell structure. Further, it can be understood that the metallic element M... 2At least two different metallic elements M selected from K, Na, Ba, Bi, Ca, Sr, Mg, Mo, B, Ce, and Sb. 2 A synergistic effect occurs between them, effectively improving the stability of the modified ternary material's core layer exhibiting a radial arrangement and its shell layer exhibiting a single-crystal morphology; if only one metal element M... 2 This prevents a synergistic effect, thus failing to improve the stability of the modified ternary material with a radially arranged core and a single-crystal shell. It's also understandable that if the core is not radially arranged, it hinders the rapid conduction of lithium ions during charge-discharge cycles, impedes uniform contraction and expansion of the material, and reduces stress release, negatively impacting rate capability and cycle performance.

[0060] In some of these examples, the modified ternary material has the chemical formula Li. 1+a [Ni x Co y Mn z M 1 b M 2 c M 3 d O2, where 0.5≤x<1, 0≤y≤0.3, 0≤z≤0.3, -0.1 <a<0.2,0<b<0.3,0<c<0.3,0≤d<0.2,x+y+z+b+c+d=1。

[0061] It is understandable that the chemical formula Li 1+a [Ni x Co y Mn z M 1 b M 2 c M 3 d O2 includes components of the core and shell; c is a variety of M 2 The sum of the moles of the elements.

[0062] Furthermore, it can be understood that x includes, but is not limited to, 0.5, 0.55, 0.6, 0.7, 0.8, 0.9, and 0.99; y includes, but is not limited to, 0, 0.05, 0.1, 0.15, 0.2, 0.25, and 0.3; z includes, but is not limited to, 0, 0.05, 0.088, 0.1, 0.15, 0.19, 0.2, 0.25, and 0.3; and a includes, but is not limited to, -0.05, 0, 0.01, 0.03, 0.06, and 0.02. a) 0.003, 0.006, 0.06, 0.1, 0.15, 0.19; b) including but not limited to 0.003, 0.006, 0.05, 0.1, 0.15, 0.2, 0.25, 0.29; c) including but not limited to 0.005, 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.29; d) including but not limited to 0, 0.002, 0.01, 0.05, 0.1, 0.15, 0.19.

[0063] It can also be understood that when y is 0, the modified ternary material is a nickel-manganese binary material; when z is 0, the modified ternary material is a nickel-cobalt binary material; and when d is 0, the chemical formula of the modified ternary material is Li. 1+a [Ni x Co y Mn z M 1 b M 2 c O2.

[0064] It can be further understood that y and z are not both 0.

[0065] In some of these examples, the modified ternary material has 0 < y ≤ 0.3 and 0 < z ≤ 0.3.

[0066] In some of these examples, the modified ternary material has 0.003 ≤ b < 0.3 and 0.005 ≤ c < 0.3.

[0067] In some of these examples, the metallic element M... 1 It is selected from at least two of Al, B, Ba, Bi, Ca, Cr, Ce, Co, Er, Ga, Ge, Ho, K, La, Mg, Mo, Na, Nb, Pd, Si, Sb, Sr, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr, and Zn.

[0068] Different kinds of metallic elements M 1 They can exert a synergistic effect, which can further improve the stability of the radially arranged core layer of the modified ternary material.

[0069] In some of these examples, the metallic element M...3 For W.

[0070] In some of these examples, the core layer of the modified ternary material has pores with a porosity of 0.001% to 10%.

[0071] It is understood that the porosity of the core layer includes, but is not limited to, 0.001%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 2%, 5%, 6%, 8%, 9%, and 10%.

[0072] In some of these examples, the width of the primary particles in the modified ternary material is 80 nm to 200 nm, and the ratio of the length to the width of the primary particles is ≥2.

[0073] Further, the length-to-width ratio of the primary particle is 2 to 10. Optionally, the length-to-width ratio of the primary particle is 5 to 8.

[0074] It is understood that the width of a primary particle includes, but is not limited to, 80nm, 90nm, 100nm, 120nm, 150nm, 180nm, and 200nm; and the ratio of the length to the width of a primary particle includes, but is not limited to, 2, 3, 4, and 5.

[0075] Further, it can be understood that multiple primary particles arranged radially in a radial pattern refers to multiple primary particles radiating outwards from the same center. It can also be understood as being emitted outwards along the length of the primary particles.

[0076] In some examples, the modified ternary material further includes a coating layer disposed on the shell surface, the composition of which includes the metallic element M. 4 oxides of metallic element M 4 It is selected from at least one of Al, B, Ba, Bi, Ca, Cr, Ce, Co, Er, Ga, Ge, Ho, K, La, Mg, Mo, Na, Nb, Pd, Si, Sb, Sr, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr, and Zn.

[0077] Please refer to Figure 2 In some examples, a modified ternary material 101 is provided, including a core layer 110 and a shell layer 120 disposed on the surface of the core layer 110, and a coating layer 130 disposed on the surface of the shell layer 120.

[0078] A coating layer is applied to the surface of the shell, which can further suppress the side reactions between the modified ternary material and the electrolyte, thereby further improving the electrochemical performance of the modified ternary material.

[0079] In some of these examples, the thickness of the coating layer in the modified ternary material is 0.001 μm to 0.5 μm.

[0080] It is understood that the thickness of the coating layer includes, but is not limited to, 0.001μm, 0.005μm, 0.01μm, 0.05μm, 0.08μm, 0.1μm, 0.2μm, 0.3μm, 0.4μm, and 0.5μm.

[0081] In some of these examples, the metallic element M... 4 Its mass accounts for 0.01% to 1% of the total mass of the core and shell.

[0082] It is understandable that the metallic element M 4 The mass of the core and shell accounts for, but is not limited to, 0.01%, 0.05%, 0.08%, 0.1%, 0.2%, 0.5%, 0.75%, 0.9%, and 1% of the total mass of the core and shell.

[0083] In some of these examples, the specific surface area of ​​the modified ternary material is 0.8 m². 2 / g~2.0m 2 / g.

[0084] It is understood that the specific surface area of ​​modified ternary materials includes, but is not limited to, 0.8 m². 2 / g, 0.9m 2 / g、1m 2 / g, 1.2m 2 / g, 1.5m 2 / g, 1.8m 2 / g、2m 2 / g.

[0085] In some of these examples, the PD (compact density) of the modified ternary material is 2.5 g / cm³. 3 ~3.3g / cm 3 .

[0086] It is understandable that the PD of modified ternary materials includes, but is not limited to, 2.5 g / cm³. 3 2.6g / cm 3 2.7g / cm 3 2.8g / cm 3 2.9g / cm 3 3.0g / cm 3 3.1g / cm 3 3.3g / cm 3 .

[0087] In some of these examples, the D50 (volume average particle size) of the modified ternary material is 2 μm to 8 μm.

[0088] It is understood that the D50 of modified ternary materials includes, but is not limited to, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, and 8μm.

[0089] In some of these examples, the average particle size of the modified ternary material is 1.2 μm to 5.2 μm.

[0090] It is understood that the average particle size of the modified ternary material includes, but is not limited to, 1.2μm, 2μm, 3μm, 4μm, 5μm, and 5.2μm.

[0091] In some of these examples, the ratio of the difference between the outer diameter of the shell and the outer diameter of the core to the outer diameter of the shell in the modified ternary material is (0.01–0.99):1.

[0092] It can be understood that the outer diameter of the shell is the diameter of the modified ternary material containing the core and shell, and the outer diameter of the core is the diameter of the core. Furthermore, it can be understood that the ratio of the difference between the outer diameter of the shell and the outer diameter of the core to the outer diameter of the shell includes, but is not limited to, 0.01:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.8:1, and 1:1.

[0093] One embodiment of the present invention provides a method for preparing a modified ternary material, comprising steps S10 to S20:

[0094] Step S10: Prepare the nickel-cobalt-manganese ternary material precursor (see...) Figure 3 Metal element M 1 The precursor and lithium source are mixed and subjected to a first sintering process to obtain a ternary material intermediate (see reference). Figure 4 The nickel-cobalt-manganese ternary material precursor consists of multiple primary particles arranged radially; the metallic element M... 1 It is selected from at least one of Al, B, Ba, Bi, Ca, Cr, Ce, Co, Er, Ga, Ge, Ho, K, La, Mg, Mo, Na, Nb, Pd, Si, Sb, Sr, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr, and Zn.

[0095] It is understandable that in step S10, the nickel-cobalt-manganese ternary material precursor with multiple primary particles arranged radially in a radial pattern, and the metal element M... 1 In the precursor and lithium source mixing step, nickel-cobalt-manganese ternary material precursor and metal element M can be mixed. 1 The precursor and lithium source are mixed, and metal element M can also be included. 1 Mixing nickel-cobalt-manganese ternary material precursors with lithium sources can also incorporate metal element M. 1 Nickel-cobalt-manganese ternary material precursors, metallic element M 1 The precursor and lithium source are mixed.

[0096] During the first sintering process, the metallic element M 1 It can effectively maintain the radiality of primary particles in the nickel-cobalt-manganese ternary material precursor, so that the ternary material intermediate maintains a radially arranged radial distribution; and it can maintain the porosity of the ternary material intermediate.

[0097] In some of these examples, in step S10, the temperature of the first sintering treatment is 600°C to 1000°C.

[0098] It is understood that the temperature of the first sintering treatment includes, but is not limited to, 600℃, 700℃, 750℃, 800℃, 850℃, 900℃, and 1000℃.

[0099] In some of these examples, in step S10, the atmosphere for the first sintering process is oxygen or air.

[0100] In some of these examples, step S10 also includes the step of crushing the obtained ternary material intermediate.

[0101] In some of these examples, step S10 also includes a step of sieving the pulverized ternary material intermediate.

[0102] Step S20: Combine the ternary material intermediate with the metallic element M 2 The precursor is mixed and subjected to a second sintering process, or the ternary material intermediate is mixed with the metallic element M. 2 Precursor and metallic element M 3 The precursors are mixed and subjected to a second sintering process; metallic element M 2 At least two elements selected from K, Na, Ba, Bi, Ca, Sr, Mg, Mo, B, Ce, and Sb; metallic element M 3 It is selected from at least one of Al, Cr, Co, Er, Ga, Ge, Ho, La, Nb, Pd, Si, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr and Zn.

[0103] After the first sintering treatment, lithium nickel cobalt manganese oxide is doped with the metal element M. 1 Doped with metal element M 1 Ternary material intermediates and metallic element M 2 The precursors are mixed and then subjected to a second sintering process, or the precursors doped with the metal element M are subjected to a second sintering process. 1 Ternary material intermediates and metallic element M 2 Precursor and metallic element M 3 After the precursors are mixed, a second sintering process is performed, involving multiple specific types of metallic elements M. 2 The synergistic effect between them further interacts with the metallic element M.1 Between, or further with metallic element M 1 and metallic element M 3 The synergistic effect between them allows the surface layer of the ternary material to rapidly fuse into a single crystal to form a shell at a lower sintering temperature, while the interior of the ternary material intermediate remains radially arranged as a core layer. This effectively improves the stability of the radially arranged core layer and the single-crystal morphology of the modified ternary material.

[0104] It is understandable that the shell is doped with the metallic element M. 1 Based on the ternary material intermediate, the metal element M is further doped. 2 and / or metallic element M 3 That is, the shell contains the metallic element M. 1 It can also be understood that in step S20, the ternary material intermediate is mixed with the metallic element M. 2 Precursor and metallic element M 3 In the precursor mixing step, the ternary material intermediate can be mixed with the metallic element M. 2 Precursor and metallic element M 3 Precursor mixing can also be used to mix ternary material intermediates with metal element M. 2 and metallic element M 3 Precursor mixing.

[0105] In some of these examples, in step S20, the temperature of the second sintering process is 600°C to 1000°C.

[0106] It is understood that the temperature of the second sintering process includes, but is not limited to, 600℃, 700℃, 750℃, 800℃, 850℃, 900℃, and 1000℃.

[0107] In some of these examples, in step S20, the atmosphere for the second sintering process is oxygen or air.

[0108] In some of these examples, step S20 also includes the addition of a lithium source.

[0109] In some examples, the preparation method of the modified ternary material further includes step S30:

[0110] The ternary material obtained from the second sintering process is combined with the metallic element M. 4 The precursor mixture undergoes a third sintering process; metallic element M 4 It is selected from at least one of Al, B, Ba, Bi, Ca, Cr, Ce, Co, Er, Ga, Ge, Ho, K, La, Mg, Mo, Na, Nb, Pd, Si, Sb, Sr, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr, and Zn.

[0111] It is understandable that the third sintering process can form metallic element M on the shell surface. 4 The oxide coating layer.

[0112] In some of these examples, in step S30, the temperature of the third sintering process is 150°C to 750°C.

[0113] It is understood that the temperature of the third sintering process includes, but is not limited to, 150℃, 200℃, 250℃, 300℃, 450℃, 500℃, 600℃, 700℃, and 750℃.

[0114] In some of these examples, in step S30, the atmosphere for the third sintering process is oxygen or air.

[0115] It is understandable that the above-mentioned modified ternary material preparation method can produce the above-mentioned modified ternary material.

[0116] The modified ternary materials prepared by the above-mentioned method have low impedance, low gas production, high initial discharge specific capacity, good cycle performance, small specific surface area, good structural stability, good mechanical properties, high compaction density, and good safety performance.

[0117] One embodiment of the present invention provides the application of the above-mentioned modified ternary material in the preparation of lithium-ion batteries.

[0118] Furthermore, one embodiment of the present invention provides the application of the modified ternary material described above or the modified ternary material prepared by the above preparation method in the preparation of lithium-ion battery cathode materials. Another embodiment of the present invention provides a lithium-ion battery cathode material comprising the modified ternary material described above or the modified ternary material prepared by the above preparation method.

[0119] The modified ternary materials described above or the modified ternary materials prepared by the above preparation methods can be used to prepare lithium-ion battery cathode materials, which can endow lithium-ion battery cathode materials with lower impedance, higher first discharge specific capacity and cycle performance.

[0120] In some embodiments, the lithium-ion battery cathode material may be the modified ternary material described above or the modified ternary material prepared by the above preparation method, that is, the lithium-ion battery cathode material may be directly prepared using the modified ternary material described above or the modified ternary material prepared by the above preparation method. In other embodiments, the lithium-ion battery cathode material may include other materials in addition to the modified ternary material described above or the modified ternary material prepared by the above preparation method.

[0121] One embodiment of the present invention provides a lithium-ion battery, including a positive electrode, a separator, and a negative electrode, wherein the positive electrode and the negative electrode are disposed on both sides of the separator, and the positive electrode includes the modified ternary material described above or the modified ternary material prepared by the above preparation method.

[0122] One embodiment of the present invention provides the application of the above-described lithium-ion battery in electronic devices, power tools, electric vehicles, or energy storage systems. Another embodiment of the present invention provides electronic devices, power tools, electric vehicles, or energy storage systems incorporating the above-described lithium-ion battery. Specific Implementation

[0124] The following examples of modified ternary materials, their preparation methods, applications, and lithium-ion batteries according to the present invention are not limited to the following embodiments.

[0125] Example 1

[0126] (1) Ni particles arranged radially in a primary pattern 0.7 Co 0.1 Mn 0.2 (OH)2, LiOH·H2O and SbO2 are mixed in a molar ratio of 1:1.05:0.003, sintered at 800℃ for 3 hours in an oxygen atmosphere, pulverized and sieved to obtain process material I;

[0127] (2) Process material I was mixed with Ba(OH)₂·8H₂O, CeO₂, and WO₃ in a molar ratio of 1:0.002:0.003:0.002, and sintered at 890℃ for 6 hours in an oxygen atmosphere. The mixture was then pulverized and sieved to obtain bulk particles containing a core and a shell. The chemical formula of the bulk particles is Li 1.05 [Ni 0.693 Co 0.099 Mn 0.198 Sb 0.003 Ba 0.002 Ce 0.003 W 0.002 O2, with the core doped with Sb and the shell doped with Sb, Ba, Ce and W;

[0128] (3) Mix the bulk particles with TeO2 (the mass of Te element is 0.1% of the mass of the bulk particles) and MoO3 (the mass of Mo element is 0.1% of the mass of the bulk particles), sinter in air at 650°C, and sieve to form a modified ternary material with a coating layer of Te and Mo element oxides.

[0129] The modified ternary material D prepared in Example 1 50 The thickness is 3.62 μm, the coating thickness is 0.01 μm, and the specific surface area is 1.0 m².2 / g, PD is 3.0g / cm 3 The average size is 2.8 μm.

[0130] A cross-sectional view of the bulk particles obtained in Example 1 is shown below. Figure 5 As shown; from Figure 5 It can be seen that the bulk particles exhibit a core-shell structure, with the core layer arranged radially and containing porosity. Using NanoMeasurer software, its porosity was measured to be 0.5%. The width of the primary particles in the core layer is 100 nm, and the length-to-width ratio of the primary particles is 5. The shell layer has a single-crystal morphology, and the ratio of the difference between the outer diameter of the shell and the outer diameter of the core layer to the outer diameter of the shell layer is 0.48:1. The scanning electron microscope image of the bulk particles is shown below. Figure 6 As shown; from Figure 6 It can be seen that the particles have a rounded appearance and good sphericity.

[0131] Example 2

[0132] The process is basically the same as in Example 1, except that step (2) is as follows:

[0133] (2) Process material I was mixed with Mg(OH)2, Sr(OH)2, and WO3, and sintered at 890℃ for 6 hours in an oxygen atmosphere. The mixture was then pulverized and sieved to obtain bulk particles containing a core and a shell. The chemical formula of the bulk particles is Li 1.05 [Ni 0.693 Co 0.099 Mn 0.198 Sb 0.003 Mg 0.002 Sr 0.003 W 0.002 O2, with Sb doped in the core and Sb, Mg, Sr and W doped in the shell.

[0134] Example 3

[0135] (1) Ni particles arranged radially in a radial pattern 0.8 Co 0.1 Mn 0.1 (OH)2, LiOH·H2O and Ta2O5 are mixed in a molar ratio of 1:1.02:0.004, sintered at 750℃ for 5 hours in an oxygen atmosphere, pulverized and sieved to obtain process material I;

[0136] (2) Process material I was mixed with B2BaO4 and sintered at 870℃ for 16 hours in an oxygen atmosphere. The mixture was then pulverized and sieved to obtain bulk particles containing a core and a shell. The chemical formula of the bulk particles is Li 1.02 [Ni 0.7888 Co 0.0986 Mn0.0986 Ta 0.00 8B 0.004 Ba 0.002 O2, with Ta doped in the core and Ta, B and Ba doped in the shell; the bulk particles have a core-shell structure, with the core arranged radially and containing pores with a porosity of 2%, the width of the primary particles in the core is 200 nm, and the ratio of the length to the width of the primary particles is 3; the shell has a single crystal morphology, and the ratio of the difference between the outer diameter of the shell and the outer diameter of the core to the outer diameter of the shell is 0.2:1;

[0137] (3) Mix the bulk particles with Y2O3 (the mass of Y element is 0.25% of the mass of the bulk particles) and WO3 (the mass of W element is 0.2% of the mass of the bulk particles), and sinter at 400°C in an oxygen atmosphere, and then sieve to form an oxide coating layer containing Y and W elements.

[0138] The D of the modified ternary material prepared 50 The surface area is 8 μm, the coating thickness is 0.05 μm, and the specific surface area is 1.1 m². 2 / g, PD is 3.1g / cm 3 The average size is 5.2 μm.

[0139] Example 4

[0140] The process is basically the same as in Example 1, except that step (1) is as follows:

[0141] (1) Ni arranged radially 0.7 Co 0.1 Mn 0.2 (OH)2, LiOH·H2O, SbO2, and Ta2O5 are mixed in a molar ratio of 1:1.05:0.003:0.0025 and sintered at 800℃ for 3 hours in an oxygen atmosphere. The mixture is then pulverized and sieved to obtain process material I.

[0142] The component chemical formula of the bulk particles obtained in step (2) is Li 1.05 [Ni 0.69 Co 0.099 Mn 0.196 Sb 0.003 Ta 0.005 Ba 0.002 Ce 0.003 W 0.002 O2.

[0143] Example 5

[0144] The process is basically the same as in Example 1, except that the amount added is adjusted, and the chemical formula of the bulk particles obtained in step (2) is Li. 1.05 [Ni 0.63Co 0.09 Mn 0.18 Sb 0.03 Ba 0.02 Ce 0.03 W 0.02 O2.

[0145] Example 6

[0146] The process is basically the same as in Example 1, except that the amount added is adjusted, and the chemical formula of the bulk particles obtained in step (2) is Li. 1.05 [Ni 0.592 Co 0.085 Mn 0.168 Sb 0.1 Ba 0.02 Ce 0.03 W 0.005 O2.

[0147] Comparative Example 1

[0148] The process is basically the same as in Example 1, except that SbO2 is not added in step (1), and Ba(OH)2·8H2O and CeO2 are not added in step (2). The chemical formula of the bulk particles is Li. 1.05 [Ni 0.7 Co 0.1 Mn 0.2 O2;

[0149] A cross-sectional view of the bulk particles prepared in Comparative Example 1 is shown below. Figure 7 As shown, a schematic diagram of the cross-sectional structure of the ternary material is as follows. Figure 8 As shown, the ternary material prepared in Comparative Example 1 has a single crystal morphology, does not have a core-shell layer, and has no radially arranged core.

[0150] Comparative Example 2

[0151] It is basically the same as Example 1, except that Ba(OH)2·8H2O and CeO2 were not added in step (2).

[0152] Comparative Example 3

[0153] It is basically the same as Example 2, except that Sr(OH)2 was not added in step (2).

[0154] Comparative Example 4

[0155] It is basically the same as Example 2, except that Mg(OH)2 was not added in step (2).

[0156] Scanning electron microscope (SEM) images of the bulk particles prepared in Comparative Examples 2, 3, and 4 are shown below. Figures 9-11 As shown, the cross-sectional structural schematic diagrams of ternary materials are all as follows. Figure 12As shown; that is, step (2) does not add the metal element M. 2 Or simply add one metallic element M 2 The outer shell has a polycrystalline morphology.

[0157] Comparative Example 5

[0158] The process is basically the same as in Example 1, except that the primary particles in the nickel-cobalt-manganese ternary material precursor are arranged in a disordered manner. 0.7 Co 0.1 Mn 0.2 (OH)2, i.e., non-radial radial arrangement.

[0159] The metal element doping of each embodiment and comparative example is shown in Table 1.

[0160] Table 1

[0161]

[0162] The modified ternary materials obtained in the examples and comparative examples were used as positive electrodes to prepare coin cells. The specific preparation method is as follows: the positive electrode active material, acetylene black and polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 95:3:2, coated on aluminum foil and dried, cut into pieces, and dried in a vacuum drying oven at 120°C for 12 hours; the negative electrode was a Li metal sheet; the separator was a polyethylene porous membrane; the electrolyte was a mixture of equal parts of 1 mol / L LiPF6, ethylene carbonate (EC) and diethyl carbonate (DEC); the 2025 type coin cells were assembled in an argon glove box with water and oxygen contents of less than 5 ppm, and coin cell tests were conducted at 2.8–4.45V. The test results are shown in Table 2.

[0163] Table 2

[0164]

[0165] As shown in Table 2, compared with the comparative example, the modified ternary material prepared in the example has a lower initial DCR, a higher initial discharge specific capacity, and better cycle performance.

[0166] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0167] The embodiments described above are merely illustrative of several implementations of the present invention, designed to facilitate a detailed understanding of the technical solutions of the present invention, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided by the present invention through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this invention patent should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A modified ternary material, characterized in that, The modified ternary material comprises a core layer and a shell layer arranged on the surface of the core layer; the core layer comprises a plurality of primary particles, the plurality of primary particles are arranged radially, a ratio of a length to a width of the primary particle is greater than or equal to 2, and a component of the core layer comprises a metal element M 1 Doped lithium nickel cobalt manganese oxide; the shell layer is a single crystal material, and a component of the shell layer comprises a metal element M 1 , and a metal element M 2 Co-doped lithium nickel cobalt manganese oxide, or a component of the shell layer comprises a metal element M 1 , a metal element M 2 , and a metal element M 3 Co-doped lithium nickel cobalt manganese oxide the metal element M 1 at least one selected from the group consisting of Al, Bi, Ca, Cr, Co, Er, Ga, Ge, Ho, K, La, Mo, Na, Nb, Pd, Si, Sb, Se, Ru, Rh, Ta, Te, Ti, V, Y, Zr, and Zn; the metal element M 2 at least two selected from Ba, Sr, Mg, B and Ce; the metal element M 3 selected from W; The modified ternary material has a component chemical formula of Li 1+a [Ni x Co y Mn z M 1 b M 2 c M 3 d ]O2, wherein 0.5≤x<1, 0≤y≤0.3, 0≤z≤0.3, -0.1<a<0.2, 0<b<0.3, 0<c<0.3, 0≤d<0.2, and x+y+z+b+c+d=1.

2. The modified ternary material of claim 1, wherein, 0.003≤b<0.3, 0.005≤c<0.

3.

3. The modified ternary material of claim 1, wherein, The core layer has pores, and the porosity is 0.001%-10%.

4. The modified ternary material of claim 1, wherein, The width of the primary particle is 80 nm-200 nm, and the ratio of the length to the width of the primary particle is 2-10.

5. The modified ternary material of any one of claims 1-4, wherein, The modified ternary material further comprises a cladding layer disposed on the surface of the shell layer, the composition of the cladding layer comprising an oxide of a metal element M 4 4 selected from at least one of Al, B, Ba, Bi, Ca, Cr, Ce, Co, Er, Ga, Ge, Ho, K, La, Mg, Mo, Na, Nb, Pd, Si, Sb, Sr, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr, and Zn.​ 6. The modified ternary material of claim 5, wherein, The thickness of the coating layer is 0.001 μm-0.5 μm.

7. The modified ternary material of any one of claims 1-4, 6, wherein, The modified ternary material comprises at least one of the following (1)-(5): (1) the specific surface area of the modified ternary material is 0.8 m 2 / g~2.0 m 2 / g; (2) the modified ternary material has a PD of 2.5 g / cm 3 3.3 g / cm 3 ; (3) The D50 of the modified ternary material is 2 μm-8 μm; (4) The average particle size of the modified ternary material is 1.2 μm-5.2 μm; (5) The ratio of the difference between the outer diameter of the shell layer and the outer diameter of the core layer to the outer diameter of the shell layer is (0.01-0.99):

1.

8. A method of preparing a modified ternary material, characterized by, The method comprises the following steps: The nickel cobalt manganese ternary material precursor, the metal element M 1 and a lithium source are mixed, a first sintering treatment is performed, and a ternary material intermediate is obtained; and mixing the ternary material intermediate with a precursor of metal element M 2 , and performing a second sintering treatment, or mixing the ternary material intermediate with a precursor of metal element M 2 and a precursor of metal element M 3 , and performing a second sintering treatment; The nickel-cobalt-manganese ternary material precursor comprises a plurality of primary particles, and the plurality of primary particles are arranged radially in a radial direction, and the ratio of the length to the width of the primary particle is ≥2. a metal element M 1 at least one selected from Al, Bi, Ca, Cr, Co, Er, Ga, Ge, Ho, K, La, Mo, Na, Nb, Pd, Si, Sb, Se, Ru, Rh, Ta, Te, Ti, V, Y, Zr and Zn; the metal element M 2 at least two selected from Ba, Sr, Mg, B and Ce; the metal element M 3 selected from W; The modified ternary material has a component chemical formula of Li 1+a [Ni x Co y Mn z M 1 b M 2 c M 3 d ]O2, wherein 0.5≤x<1, 0≤y≤0.3, 0≤z≤0.3, -0.1<a<0.2, 0<b<0.3, 0<c<0.3, 0≤d<0.2, and x+y+z+b+c+d=1.

9. The method for preparing the modified ternary material as described in claim 8, characterized in that, In the second sintering treatment step, a step of adding a lithium source is further included.

10. The method of producing a modified ternary material according to any one of claims 8 to 9, wherein Also included is a step of performing a third sintering treatment on a mixture of the ternary material obtained from the second sintering treatment and a metal element M 4 selected from at least one of Al, B, Ba, Bi, Ca, Cr, Ce, Co, Er, Ga, Ge, Ho, K, La, Mg, Mo, Na, Nb, Pd, Si, Sb, Sr, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr, and Zn. 4 selected from at least one of Al, B, Ba, Bi, Ca, Cr, Ce, Co, Er, Ga, Ge, Ho, K, La, Mg, Mo, Na, Nb, Pd, Si, Sb, Sr, Se, Ru, Rh, Ta, Te, Ti, W, V, Y, Zr, and Zn.

11. The method of claim 10, wherein the modified ternary material is prepared by a process comprising: The preparation method comprises at least one of the following (1)-(3): (1) The temperature of the first sintering treatment is 600°C-1000°C; (2) The temperature of the second sintering treatment is 600°C-1000°C; (3) The temperature of the third sintering treatment is 150°C-750°C.

12. A lithium-ion battery, characterized by, The positive electrode and the negative electrode are arranged on two sides of the separator, the positive electrode comprises the modified ternary material according to any one of claims 1-7 or the modified ternary material prepared by the preparation method according to any one of claims 8-11.

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