Ternary cathode material, preparation method and application thereof

Abstract

The present application relates to a ternary positive electrode material, its preparation method and application, and belongs to the technical field of lithium-ion battery materials. The present application provides a ternary positive electrode material, comprising a ternary positive electrode material matrix and a coating layer, wherein the surface of the ternary positive electrode material matrix is ​​coated with the coating layer; the ternary positive electrode material matrix comprises a chemical formula of LiNi x Co y M 1‑x‑y The material of the O2 is selected from the group consisting of Mn, Al, Mg, Ti, Zr, Y, Nb, W, Ce, Sb, Sr, and Ta, with 0.50 < x ≤ 0.98, 0 ≤ y < 0.25, and x + y ≤ 1; and the coating layer comprises polyhedral oligomeric silsesquioxane (POSS). This ternary cathode material can effectively inhibit the adhesion of moisture in the air to the material surface, improving its adaptability to storage environments, extending storage time, and thereby enhancing the cycling performance of lithium-ion batteries.

Description

Technical Field

[0001] The present application relates to the technical field of lithium-ion battery materials, and in particular to a ternary positive electrode material, a preparation method thereof, and applications thereof. Background Art

[0002] The mature application of lithium-ion batteries in electric vehicles and power tools has driven the current development of power batteries to pursue long-range and high safety. Currently, high-nickel, low-cobalt and medium-nickel, high-voltage applications have become two major research directions for lithium-ion battery cathode materials. Compared with polycrystalline materials, single-crystal materials have advantages in compressive resistance and structural stability. However, they have problems such as large specific surface area and strong water absorption, which lead to the dissolution of active lithium and the increase of residual alkali, thereby increasing the risk of failure (agglomeration and waste) during cathode slurry preparation. Increased moisture content in the material also affects the coating effect of the electrode and the cycle performance of the battery, greatly limiting the development and application of medium- and high-nickel single-crystal materials. Summary of the Invention

[0003] Based on this, it is necessary to provide a ternary positive electrode material, its preparation method and application, so as to effectively inhibit the adhesion of moisture in the air to the surface of the ternary positive electrode material, improve its adaptability to the storage environment, prolong the storage time, and thereby improve the cycle performance of lithium-ion batteries.

[0004] The technical solutions adopted in this application are as follows:

[0005] In a first aspect, the present application provides a ternary positive electrode material, comprising a ternary positive electrode material substrate and a coating layer, wherein the surface of the ternary positive electrode material substrate is coated with the coating layer;

[0006] The ternary positive electrode material matrix includes a chemical formula of LiNi x Co y M 1-x-y O2 material, wherein M includes one or more of Mn, Al, Mg, Ti, Zr, Y, Nb, W, Ce, Sb, Sr and Ta, 0.50<x≤0.98, 0≤y<0.25, x+y≤1; the material of the coating layer includes polyhedral oligomeric silsesquioxane.

[0007] In some embodiments, the polyhedral oligomeric silsesquioxane includes one or more of polyhedral oligomeric silsesquioxane-alkyl, polyhedral oligomeric silsesquioxane-phenyl, polyhedral oligomeric silsesquioxane-alkenyl, polyhedral oligomeric silsesquioxane-amino, polyhedral oligomeric silsesquioxane-hydroxy, and polyhedral oligomeric silsesquioxane-acrylate.

[0008] In some embodiments, the mass ratio of the coating layer to the ternary cathode material matrix is ​​(0.0001-0.05):1;

[0009] Optionally, the specific surface area of ​​the ternary cathode material matrix is ​​0.4 m 2 / g~2.5m 2 / g.

[0010] In a second aspect, the present application provides a method for preparing the above-mentioned ternary cathode material, comprising the following steps:

[0011] preparing a ternary cathode material matrix;

[0012] The ternary positive electrode material matrix is ​​mixed with the material of the coating layer and subjected to a first calcination treatment.

[0013] In some embodiments, the process conditions of the first calcination treatment include: a first calcination temperature of 260° C. to 700° C., and a first calcination time of 4 hours to 12 hours.

[0014] In some embodiments, the method for preparing the ternary cathode material matrix comprises the following steps:

[0015] S1. Mixing a ternary cathode material matrix precursor, a metal compound, and a first lithium source to obtain an intermediate A;

[0016] S2. The intermediate A is pre-treated by calcination to obtain intermediate B;

[0017] S3. The intermediate B is mixed with a second lithium source and then subjected to a second calcination treatment to obtain the ternary positive electrode material matrix.

[0018] In some embodiments, the ternary cathode material matrix precursor in step S1 includes a chemical formula of Ni x Co y M 1-x-y (OH)2 material, wherein 0.50<x≤0.98, 0≤y<0.25, x+y≤1.

[0019] In some embodiments, the metal compound in step S1 includes one or more compounds of Al, Mg, Ti, Zr, Y, Nb, W, Ce, Sb, Sr, and Ta.

[0020] In some embodiments, the Li in the first lithium source in step S1 is calculated by molar ratio. + : The metal element in the metal compound: the ternary positive electrode material matrix precursor = (0.50~1.06): (0~0.02): 1.

[0021] In some embodiments, the first lithium source in step S1 and the second lithium source in step S3 each independently include one or more of lithium hydroxide and lithium carbonate.

[0022] In some embodiments, the process conditions of the calcination pretreatment in step S2 include: a calcination pretreatment temperature of 400° C. to 650° C., and a calcination pretreatment time of 3 h to 10 h.

[0023] In some embodiments, the Li in the second lithium source in step S3 is calculated by molar ratio. + : The intermediate B = (0-0.55): 1.

[0024] In some embodiments, the second calcination temperature in step S3 is 600° C. to 1100° C., and the second calcination time is 6 h to 20 h.

[0025] In a third aspect, the present application provides a positive electrode plate, comprising the above-mentioned ternary positive electrode material or the ternary positive electrode material prepared by the above-mentioned preparation method.

[0026] In a fourth aspect, the present application provides a lithium-ion battery comprising the above-mentioned positive electrode plate.

[0027] In a fifth aspect, the present application provides an electrical device comprising the above-mentioned lithium-ion battery.

[0028] Compared with traditional technologies, the above-mentioned ternary cathode materials, their preparation methods and applications have at least the following advantages:

[0029] (1) The material of the above-mentioned coating layer includes polyhedral oligomeric silsesquioxane (POSS), which is coated on the surface of the ternary positive electrode material matrix to produce a superhydrophobic effect. The inorganic layer in the coating layer is tightly combined with the ternary positive electrode material matrix on the inside, and the organic layer in the coating layer is in contact with the air on the outside, which can effectively reduce the hygroscopicity of the ternary positive electrode material, improve the adaptability of the ternary positive electrode material to the storage environment, and extend the storage time of the ternary positive electrode material.

[0030] (2) The superhydrophobic coating can restrain the expansion and extension of microcracks, absorb energy, and reduce the stress concentration of the matrix of the ternary cathode material. Its organic active sites can increase the crosslinking degree and compatibility of the system, improve the mechanical properties and strength of the ternary cathode material, maintain the structural stability of the ternary cathode material, and thus improve the cycle retention rate of the lithium-ion battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is the SEM image of the ternary positive electrode material prepared in Example 1 of the present application.

[0032] Figure 2 This is the SEM image of the ternary positive electrode material prepared in Example 4 of the present application.

[0033] Figure 3 This is the XRD pattern of the ternary positive electrode material prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0034] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar modifications without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0035] In the description of this application, unless otherwise defined, technical terms and professional words not explicitly stated have the same meaning as commonly understood by those skilled in the art and are common knowledge to those skilled in the art. Methods not explicitly stated are conventional methods known to those skilled in the art. The term "multiple" in this application means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0036] In this application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0037] One embodiment of the present application provides a ternary positive electrode material, comprising a ternary positive electrode material substrate and a coating layer, wherein the surface of the ternary positive electrode material substrate is coated with the coating layer;

[0038] The ternary cathode material matrix includes a chemical formula of LiNi x Co y M 1-x-y O2 material, wherein M includes one or more of Mn, Al, Mg, Ti, Zr, Y, Nb, W, Ce, Sb, Sr and Ta, 0.50<x≤0.98, 0≤y<0.25, x+y≤1; the material of the coating layer includes polyhedral oligomeric silsesquioxane.

[0039] The coating layer on the surface of the above-mentioned ternary positive electrode material matrix is ​​super hydrophobic and has an organic-inorganic composite structure. The inorganic layer of the hydrophobic coating layer is tightly combined with the ternary positive electrode material matrix on the inside, and the organic layer of the hydrophobic coating layer is in contact with the air on the outside, which can effectively reduce the hygroscopicity of the ternary positive electrode material. Therefore, the hydrophobic coating layer can improve the adaptability of the ternary positive electrode material to the storage environment and extend the storage time of the ternary positive electrode material; the super hydrophobic coating layer can restrain the expansion and extension of microcracks, absorb energy, and reduce the stress concentration of the ternary positive electrode material matrix. Its organic active sites can increase the cross-linking degree and compatibility of the system, improve the mechanical properties and strength of the material, thereby maintaining the structural stability of the material and improving the cycle retention rate of the lithium-ion battery; the specific cage structure and intramolecular porous channels of the coating layer are conducive to the conduction of lithium ions and improve the kinetic properties of the main material. It can be understood that x can be, for example, 0.51, 0.52, 0.53, 0.54, 0.55, 0.57, 0.59, 0.60, 0.62, 0.65, 0.70, 0.80, 0.90, 0.95 or 0.98, and y can be, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.10, 0.15, 0.20, 0.22 or 0.24.

[0040] In some embodiments, the polyhedral oligomeric silsesquioxane includes one or more of polyhedral oligomeric silsesquioxane-alkyl, polyhedral oligomeric silsesquioxane-phenyl, polyhedral oligomeric silsesquioxane-alkenyl, polyhedral oligomeric silsesquioxane-amino, polyhedral oligomeric silsesquioxane-hydroxy, and polyhedral oligomeric silsesquioxane-acrylate.

[0041] In some embodiments, the mass ratio of the coating layer to the ternary cathode material matrix is ​​(0.0001-0.05): 1. It is understood that the mass ratio of the coating layer to the ternary cathode material matrix can be any value between (0.0001-0.05): 1, for example: 0.0001: 1, 0.0002: 1, 0.0003: 1, 0.0005: 1, 0.0008: 1, 0.001: 1, 0.005: 1, 0.008: 1, 0.01: 1, 0.02: 1, 0.03: 1, 0.04: 1 or 0.05: 1. It should be noted that the mass ratio of the coating layer to the ternary positive electrode material matrix cannot be too high or too low. When the mass ratio is too high, the coating layer is thicker, which will affect the transmission speed of lithium ions. When the mass ratio is too low, the coating layer is thinner and may not be able to effectively reduce the hygroscopicity of the ternary positive electrode material.

[0042] In some embodiments, the coating layer is a continuous layer coating, that is, the coating layer can fully coat the ternary cathode material matrix.

[0043] In some embodiments, the specific surface area of ​​the ternary cathode material matrix is ​​0.4 m 2 / g~2.5m 2 / g. It is understood that the specific surface area of ​​the ternary cathode material matrix can be, for example, 0.4m 2 / g, 0.5m 2 / g, 0.6m 2 / g, 0.7m 2 / g, 0.8m 2 / g, 0.9m 2 / g、1m 2 / g, 1.2m 2 / g, 1.5m 2 / g, 1.7m 2 / g, 2m 2 / g, 2.2m 2 / g, 2.5m 2 / g. The specific surface area of ​​the ternary cathode material matrix is ​​controlled to be 0.4m 2 / g~2.5m 2 / g is to achieve the best hydrophobic effect for the ternary positive electrode material without affecting its kinetic performance.

[0044] Another embodiment of the present application provides a method for preparing the above-mentioned ternary cathode material, comprising the following steps:

[0045] preparing a ternary cathode material matrix;

[0046] The ternary positive electrode material matrix and the coating layer material are mixed and subjected to a first calcination treatment.

[0047] In some embodiments, the process conditions of the first calcination treatment include: a first calcination temperature of 260° C. to 700° C., and a first calcination time of 4 to 12 hours. It is understood that the first calcination temperature can be, for example, 260° C., 280° C., 3000° C., 320° C., 350° C., 370° C., 400° C., 410° C., 430° C., 470° C., 490° C., 500° C., 550° C., 600° C., 650° C., or 700° C., and the first calcination temperature can also be other values ​​between 260° C. and 700° C.; the first calcination time can be any value between 4 and 12 hours, for example, 4 hours, 4.2 hours, 4.5 hours, 4.7 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours.

[0048] In some embodiments, the method for preparing the ternary cathode material matrix comprises the following steps:

[0049] S1. Mixing a ternary cathode material matrix precursor, a metal compound, and a first lithium source to obtain an intermediate A;

[0050] S2. The intermediate A is pretreated by calcination to obtain intermediate B;

[0051] S3. The intermediate B is mixed with a second lithium source and then subjected to a second calcination treatment to obtain a ternary positive electrode material matrix.

[0052] In some embodiments, the precursor of the ternary cathode material matrix in step S1 includes a chemical formula of Ni x Co y M 1-x-y (OH)2 material, wherein 0.50<x≤0.98, 0≤y<0.25, x+y≤1. It should be noted that the present application has no special restrictions on the source of the ternary positive electrode material matrix precursor, which can be purchased from the market or prepared according to conventional methods well known to those skilled in the art. It can be understood that x can be, for example, 0.51, 0.52, 0.53, 0.54, 0.55, 0.57, 0.59, 0.60, 0.62, 0.65, 0.70, 0.80, 0.90, 0.95 or 0.98, and y can be, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.10, 0.15, 0.20, 0.22 or 0.24.

[0053] In some embodiments, the metal compound in step S1 includes one or more compounds of Al, Mg, Ti, Zr, Y, Nb, W, Ce, Sb, Sr, and Ta. It should be noted that the metal compound can be an oxide, hydroxide, or carbonate of the above metals, for example: Al2O3, MgO, TiO2, ZrO2, Y2O3, Nb2O5, WO3, CeO2, Sb2O3, Sb2O5, SrO, Ta2O5, Al(OH)3, Mg(OH)2, Zr(OH)4, Ti(OH)4, Sr(OH)2, Al2(CO3)3, MgCO3, SrCO3, or Zr3(CO3)O5, etc.

[0054] In some embodiments, the Li in the first lithium source in step S1 is calculated by molar ratio. + : Metal element in metal compound: ternary cathode material matrix precursor = (0.50-1.06): (0-0.02): 1. It can be understood that the molar amount of the metal compound in step S1 can be 0. When the mass of the metal compound in step S1 is not 0, the Li in the first lithium source in step S1 +: The molar ratio of the metal element in the metal compound: the ternary positive electrode material matrix precursor can be, for example, 0.50:0.001:1, 0.51:0.002:1, 0.57:0.005:1, 0.60:0.007:1, 0.72:0.009:1, 0.80:0.01:1, 0.90:0.015:1, 0.95:0.017:1, 1.00:0.019:1 or 1.06:0.02:1, etc.; the purpose of adding metal compounds in the present application is to enable the metal elements to play a supporting role between the transition metal layers and to increase the kinetic properties of the ternary positive electrode material, thereby ensuring the stability of the layered structure of the ternary positive electrode material and improving the transportability of lithium ions.

[0055] In some embodiments, the first lithium source in step S1 and the second lithium source in step S3 each independently include one or more of lithium hydroxide and lithium carbonate.

[0056] In some embodiments, the process conditions of the calcination pretreatment in step S2 include: a calcination pretreatment temperature of 400° C. to 650° C., and a calcination pretreatment time of 3 h to 10 h. It is understood that the calcination pretreatment temperature may be, for example, 400° C., 420° C., 435° C., 450° C., 465° C., 480° C., 500° C., 550° C., 600° C., or 650° C., and the calcination pretreatment temperature may also be other values ​​between 400° C. and 650° C.; the calcination pretreatment time may be 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 6 h, 7 h, 8.5 h, or 10 h, and may also be other values ​​between 3 h and 10 h.

[0057] In some embodiments, the Li in the second lithium source in step S3 is calculated by molar ratio. + : Intermediate B = (0-0.55): 1. It should be noted that when the composition of the intermediate B is the same as that of the ternary cathode material matrix, no lithium supplementation is required. At this time, the mass of the second lithium source in step S3 is 0. When the composition of the intermediate B is different from that of the ternary cathode material matrix, a second lithium source needs to be added for lithium supplementation. At this time, the Li + The molar ratio to intermediate B may be, for example, 0.01:1, 0.015:1, 0.018:1, 0.02:1, 0.025:1, 0.027:1, 0.03:1, 0.035:1, 0.04:1, 0.045:1, 0.05:1 or 0.055:1.

[0058] In some embodiments, the second calcination temperature in step S3 is 600° C. to 1100° C., and the second calcination time is 6 h to 20 h. It is understood that the second calcination temperature in step S3 can be, for example, 600° C., 620° C., 650° C., 670° C., 700° C., 800° C., 900° C., 1000° C., or 1100° C., and the second calcination time can be, for example, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, or 20 h.

[0059] Another embodiment of the present application provides a positive electrode sheet, comprising the above-mentioned ternary positive electrode material or the ternary positive electrode material prepared by the above-mentioned preparation method. It should be noted that the above-mentioned positive electrode sheet can be prepared by adding the above-mentioned ternary positive electrode material or the ternary positive electrode material prepared by the above-mentioned preparation method, a conductive agent, and a binder raw material, stirring the mixture with a solvent to form a positive electrode slurry, coating the mixture on aluminum foil, and drying the mixture. The conductive agent, binder, and solvent can be those commonly used in the art.

[0060] Another embodiment of the present application provides a lithium-ion battery comprising the above-mentioned positive electrode sheet. It should be noted that the above-mentioned lithium-ion battery can be assembled with a housing after laminating or winding the positive electrode sheet, the separator, and the negative electrode sheet, and the housing is further injected with an electrolyte. The negative electrode active material attached to the negative electrode sheet can be, for example, one or more of graphite, hard carbon, silicon material, lithium titanate, and metallic lithium. The above-mentioned separator and electrolyte can be those commonly used in the art.

[0061] Another embodiment of the present application provides an electrical device comprising the above-mentioned lithium-ion battery. It should be noted that the above-mentioned lithium-ion battery can be used as a power source or energy storage unit in the electrical device, including but not limited to electric vehicles, smart home appliances, computers, mobile phones, digital cameras, etc.

[0062] The present application is further described in detail below with reference to specific examples and comparative examples. The experimental raw materials used in the following examples and comparative examples of the present application can be purchased from the market or prepared according to conventional methods well known to those skilled in the art.

[0063] In the following examples and comparative examples, POSS-NH2 is selected from Xi'an Qiyue Biotechnology POSS-aminopropyl isooctyl cage-shaped silsesquioxane, and POSS-acrylate is selected from Xi'an Qiyue Biotechnology POSS-ethyl methacrylate cage-shaped silsesquioxane.

[0064] Example 1

[0065] In this embodiment, the precursor of the ternary cathode material matrix is ​​Ni 0.55 Co 0.05 Mn 0.40(OH)2, the first lithium source and the second lithium source are both Li2CO3.

[0066] The preparation method of the ternary positive electrode material matrix comprises the following steps:

[0067] S1. According to Li2CO3:Ni 0.55 Co 0.05 Mn 0.40 The ingredients were prepared at a molar ratio of (OH)2=0.95:1 and mixed thoroughly to obtain intermediate A;

[0068] S2. Pre-calcining intermediate A at 650 ° C for 6 h to obtain intermediate B;

[0069] S3. Prepare the ingredients in a molar ratio of intermediate B: Li2CO3 = 1:0.08, mix thoroughly, and calcine at 890 ° C for 14 h to obtain a specific surface area of ​​(1.25 ± 0.2) m 2 / g of ternary cathode material matrix, whose chemical formula is LiNi 0.55 Co 0.05 Mn 0.40 O2.

[0070] Prepare the ternary cathode material as follows:

[0071] LiNi 0.55 Co 0.05 Mn 0.40 O2 and POSS-NH2 were prepared in a mass ratio of 1:0.003, mixed thoroughly, and calcined at 300℃ for 8h to form a LiNi 0.55 Co 0.05 Mn 0.40 The surface of O2 is coated with POSS-NH2 to obtain the ternary cathode material LiNi 0.55 Co 0.05 Mn 0.40 O2@POSS-NH2.

[0072] Example 2

[0073] In this embodiment, the precursor of the ternary cathode material matrix is ​​Ni 0.62 Co 0.25 Mn 0.13 (OH)2, the first lithium source is Li2CO3, and the second lithium source is LiOH.

[0074] The preparation method of the ternary positive electrode material matrix comprises the following steps:

[0075] S1. According to Li2CO3:Ni 0.62 Co 0.25 Mn 0.13The ingredients were prepared at a molar ratio of (OH)2=0.75:1 and mixed thoroughly to obtain intermediate A;

[0076] S2. Pre-calcining intermediate A at 600 ° C for 6 h to obtain intermediate B;

[0077] S3. Prepare the ingredients according to the molar ratio of intermediate B: LiOH = 1:0.27, mix thoroughly and calcine at 860 ° C for 11 hours to obtain a specific surface area of ​​(0.85 ± 0.2) m 2 / g of ternary cathode material matrix, whose chemical formula is LiNi 0.62 Co 0.25 Mn 0.13 O2.

[0078] Prepare the ternary cathode material as follows:

[0079] LiNi 0.62 Co 0.25 Mn 0.13 O2 and POSS-acrylate were prepared in a mass ratio of 1:0.002, mixed thoroughly, and calcined at 300 °C for 8 h to form a LiNi 0.62 Co 0.25 Mn 0.13 The surface of O2 is coated with POSS-acrylate to obtain the ternary cathode material LiNi 0.55 Co 0.05 Mn 0.40 O2@POSS-acrylate.

[0080] Example 3

[0081] In this embodiment, the precursor of the ternary cathode material matrix is ​​Ni 0.78 Co 0.12 Al 0.10 (OH)2, the first lithium source and the second lithium source are both Li2CO3.

[0082] The preparation method of the ternary positive electrode material matrix comprises the following steps:

[0083] S1. According to Li2CO3:Ni 0.78 Co 0.12 Al 0.10 The ingredients were prepared at a molar ratio of (OH)2=0.90:1 and mixed thoroughly to obtain intermediate A;

[0084] S2. Pre-calcining intermediate A at 600 ° C for 4 h to obtain intermediate B;

[0085] S3. Prepare the ingredients in a molar ratio of intermediate B: Li2CO3 = 1:0.15, mix thoroughly, and calcine at 800 ° C for 15 h to obtain a specific surface area of ​​(2.0 ± 0.2) m 2 / g of ternary cathode material matrix, whose chemical formula is LiNi 0.78 Co 0.12 Al 0.10 O2.

[0086] Prepare the ternary cathode material as follows:

[0087] LiNi 0.78 Co 0.12 Al 0.10 O2, POSS-NH2 and POSS-acrylate were prepared in a mass ratio of 1:0.001:0.001, mixed thoroughly and calcined at 270 °C for 6 h to form a LiNi 0.78 Co 0.12 Al 0.10 The surface of O2 is coated with POSS-NH2 and POSS-acrylate to obtain the ternary cathode material LiNi 0.78 Co 0.12 Al 0.10 O2@POSS-NH2 / POSS-acrylate.

[0088] Example 4

[0089] In this embodiment, the precursor of the ternary cathode material matrix is ​​Ni 0.82 Co 0.06 Mn 0.12 (OH)2, the first lithium source and the second lithium source are both LiOH, and the metal compound is TiO2.

[0090] The preparation method of the ternary positive electrode material matrix comprises the following steps:

[0091] S1. According to LiOH:TiO2:Ni 0.82 Co 0.06 Mn 0.12 The ingredients were prepared in a molar ratio of (OH)2=0.95:0.005:1 and mixed thoroughly to obtain intermediate A;

[0092] S2. Pre-calcining intermediate A at 550 ° C for 5 h to obtain intermediate B;

[0093] S3. Prepare the ingredients according to the molar ratio of intermediate B: LiOH = 1:0.08, mix thoroughly and calcine at 760 ° C for 12 h to obtain a specific surface area of ​​(0.45 ± 0.1) m 2 / g of ternary cathode material matrix, whose chemical formula is LiNi 0.815 Co0.060 Mn 0.120 Ti 0.005 O2.

[0094] Prepare the ternary cathode material as follows:

[0095] LiNi 0.815 Co 0.060 Mn 0.120 Ti 0.005 O2 and POSS-NH2 were prepared in a mass ratio of 1:0.003, mixed thoroughly, and calcined at 270 °C for 6 h to form a LiNi 0.815 Co 0.060 Mn 0.120 Ti 0.005 The surface of O2 is coated with POSS-NH2 to obtain the ternary cathode material LiNi 0.815 Co 0.060 Mn 0.120 Ti 0.005 O2@POSS-NH2.

[0096] Example 5

[0097] In this embodiment, the precursor of the ternary cathode material matrix is ​​Ni 0.90 Co 0.06 Mn 0.04 (OH)2, the first lithium source and the second lithium source are both LiOH, and the metal compounds are Al2O3 and ZrO2.

[0098] The preparation method of the ternary positive electrode material matrix comprises the following steps:

[0099] S1. According to LiOH:Al2O3:ZrO2:Ni 0.90 Co 0.06 Mn 0.04 The ingredients were prepared in a molar ratio of (OH)2=1.02:0.003:0.004:1 and mixed thoroughly to obtain intermediate A;

[0100] S2. Pre-calcining intermediate A at 550 ° C for 5 h to obtain intermediate B;

[0101] S3. Prepare the ingredients according to the molar ratio of intermediate B: LiOH = 1:0.03, mix thoroughly and calcine at 770 ° C for 10 h to obtain a specific surface area of ​​(0.60 ± 0.15) m 2 / g of ternary cathode material matrix, whose chemical formula is LiNi 0.890 Co 0.060 Mn 0.040 Al 0.006 Zr 0.004 O2.

[0102] Prepare the ternary cathode material as follows:

[0103] LiNi 0.890 Co 0.060 Mn 0.040 Al 0.006 Zr 0.004 O2 and POSS-NH2 were prepared in a mass ratio of 1:0.005, mixed thoroughly, and calcined at 290 °C for 6 h to form a LiNi 0.890 Co 0.060 Mn 0.040 Al 0.006 Zr 0.004 The surface of O2 is coated with POSS-NH2 to obtain the ternary cathode material LiNi 0.890 Co 0.060 Mn 0.040 Al 0.006 Zr 0.004 O2@POSS-NH2.

[0104] Example 6

[0105] The same as Example 1, except that when preparing the ternary positive electrode material, LiNi 0.55 Co 0.05 Mn 0.40 O2 and POSS-NH2 are prepared in a mass ratio of 1:0.001.

[0106] Example 7

[0107] The same as Example 1, except that when preparing the ternary positive electrode material, LiNi 0.55 Co 0.05 Mn 0.40 O2 and POSS-NH2 are prepared in a mass ratio of 1:0.05.

[0108] Comparative Example 1

[0109] The same as Example 1, except that when preparing the ternary positive electrode material, LiNi 0.55 Co 0.05 Mn 0.40 O2 was calcined at 300℃ for 8h to obtain the ternary cathode material LiNi 0.55 Co 0.05 Mn 0.40 O2.

[0110] SEM test and XRD test

[0111] The morphology of the ternary cathode material prepared in Example 1 was characterized by scanning electron microscopy. Figure 1As shown in Table 1, it can be seen that the surface of the ternary cathode material prepared in Example 1 is smooth and uniform without any aggregates.

[0112] The XRD test was performed on the ternary cathode material prepared in Example 1, and the results were as follows: Figure 3 As shown, it can be seen that the ternary positive electrode material has sharp diffraction peaks, indicating that the crystal structure is good and the crystallinity is high.

[0113] The morphology of the ternary cathode material obtained in Example 4 was characterized using a scanning electron microscope. Figure 2 As shown, it can be seen that the surface of the ternary positive electrode material is smooth and uniform, without aggregates. Since the coating layer material POSS-NH2 in the ternary positive electrode material of Example 4 accounts for a small proportion, and the crystallinity of the coating layer material POSS-NH2 is much lower than that of the ternary positive electrode material matrix, it is not easy to be detected. Therefore, Figure 2 The peak shape of the coating material is not shown.

[0114] Moisture content test

[0115] The moisture content of the ternary positive electrode materials prepared in Examples 1 to 7 and Comparative Example 1 was tested under two conditions: a temperature of 25°C and a relative humidity of 40%, and a temperature of 25°C and a relative humidity of 80%. The tested storage days were 0 days, 1 day, 10 days, 30 days and 60 days. The results are shown in Table 1.

[0116] Table 1

[0117]

[0118]

[0119] It can be seen from the data in Table 1 that the ternary positive electrode materials prepared in Examples 1 to 7 are stored at 25°C and relative humidity of 40% and 80%, and the moisture content of the samples increases only slightly. This is because a POSS-based hydrophobic coating layer is formed on the surface of the ternary positive electrode material; in Comparative Example 1, since no coating layer is formed, the sample absorbs water severely, resulting in a significant increase in moisture content.

[0120] Electrochemical performance test

[0121] The ternary cathode materials prepared in Examples 1 to 7 and Comparative Example 1 were assembled into button batteries. The test conditions included: LR2032, 0.1C, 2.5-4.3V, vs. Li + / Li; The positive electrode sheet of the button battery was prepared according to the mass ratio of positive electrode material: conductive agent: PVDF = 95:3:2. The assembled button battery was charged and discharged at a constant current of 0.3C in a voltage range of 2.5V to 4.25V for 100 cycles at a constant temperature of 45°C. The test results are shown in Table 2.

[0122] Table 2

[0123]

[0124]

[0125] As can be seen from Table 2, compared with Comparative Example 1, Example 1 is a battery assembled with a ternary positive electrode material having a POSS-based hydrophobic coating, and its discharge specific capacity, initial efficiency and 100-week capacity retention rate are improved. This is due to the special cage structure of the coating layer that can maintain structural stability, and the porous channels in the coating layer are conducive to the conduction of lithium ions; the super-hydrophobic coating in Example 1 can make the ternary positive electrode material stably exist without failure under high humidity environment, and still have stable electrochemical performance after 60 days of storage.

[0126] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.

[0127] The above-described embodiments merely represent several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make a number of variations and improvements without departing from the concept of the present application, and these variations and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the patent application shall be based on the appended claims, and the description and drawings may be used to interpret the content of the claims.

Claims

1. A ternary cathode material, characterized in that: It comprises a ternary positive electrode material matrix and a coating layer, wherein the surface of the ternary positive electrode material matrix is ​​coated with the coating layer; The ternary positive electrode material matrix includes a chemical formula of LiNi x Co y M 1-x-y O2 material, wherein M includes one or more of Mn, Al, Mg, Ti, Zr, Y, Nb, W, Ce, Sb, Sr and Ta, 0.50<x≤0.98, 0≤y<0.25, x+y≤1; the material of the coating layer includes polyhedral oligomeric silsesquioxane; The polyhedral oligomeric silsesquioxane includes one or more of polyhedral oligomeric silsesquioxane-alkyl, polyhedral oligomeric silsesquioxane-phenyl, polyhedral oligomeric silsesquioxane-alkenyl, polyhedral oligomeric silsesquioxane-amino, polyhedral oligomeric silsesquioxane-hydroxyl and polyhedral oligomeric silsesquioxane-acrylate; the mass ratio of the coating layer to the ternary positive electrode material matrix is ​​(0.0001-0.05):1; The polyhedral oligomeric silsesquioxane has a cage-like structure; The ternary cathode material matrix is ​​prepared by the following method: The precursor of the ternary positive electrode material matrix, the metal compound and the first lithium source are mixed to obtain an intermediate A; the intermediate A is subjected to a calcination pretreatment to obtain an intermediate B; the intermediate B is mixed with a second lithium source and subjected to a second calcination treatment to obtain the ternary positive electrode material matrix; the ternary positive electrode material matrix precursor includes a chemical formula of Ni x Co y M 1-x-y (OH)2 material, wherein 0.50<x≤0.98, 0≤y<0.25, x+y≤1; the metal compound includes one or more compounds of Al, Mg, Ti, Zr, Y, Nb, W, Ce, Sb, Sr and Ta; the first lithium source and the second lithium source each independently include one or more of lithium hydroxide and lithium carbonate.

2. The ternary cathode material according to claim 1, characterized in that The specific surface area of ​​the ternary positive electrode material matrix is ​​0.4 m 2 / g~2.5m 2 / g.

3. The method for preparing the ternary cathode material according to any one of claims 1 to 2, wherein: The following steps are involved: preparing a ternary cathode material matrix; S1. Mixing a ternary cathode material matrix precursor, a metal compound, and a first lithium source to obtain an intermediate A; S2. The intermediate A is pre-treated by calcination to obtain intermediate B; S3. The intermediate B is mixed with a second lithium source and subjected to a second calcination treatment to obtain the ternary cathode material matrix; S4. The ternary cathode material matrix is ​​mixed with the coating layer material and subjected to a first calcination treatment; The ternary cathode material matrix precursor includes a chemical formula of Ni x Co y M 1-x-y (OH)2 material, wherein 0.50<x≤0.98, 0≤y<0.25, x+y≤1; the metal compound includes one or more compounds of Al, Mg, Ti, Zr, Y, Nb, W, Ce, Sb, Sr and Ta; the first lithium source and the second lithium source each independently include one or more of lithium hydroxide and lithium carbonate.

4. The preparation method according to claim 3, characterized in that The process conditions of the first calcination treatment include: a first calcination temperature of 260° C. to 700° C., and a first calcination time of 4 hours to 12 hours.

5. The preparation method according to claim 3, characterized in that In terms of molar ratio, the Li + : The metal element in the metal compound: the ternary positive electrode material matrix precursor = (0.50~1.06): (0.001~0.02):

1.

6. The preparation method according to claim 3, characterized in that The process conditions of the calcination pretreatment in step S2 include: a calcination pretreatment temperature of 400° C. to 650° C., and a calcination pretreatment time of 3 h to 10 h.

7. The preparation method according to claim 3, characterized in that In terms of molar ratio, the Li + : The intermediate B = (0.01-0.55):

1.

8. In step S3 according to any one of claims 3 to 7, the second calcination temperature is 600°C to 1100°C, and the second calcination time is 6 hours to 20 hours.

9. A positive electrode plate, characterized in that: The invention comprises the ternary positive electrode material according to any one of claims 1 to 2 or the ternary positive electrode material prepared by the preparation method according to any one of claims 3 to 8.

10. A lithium ion battery, characterized in that: Including the positive electrode sheet according to claim 9.

11. An electrical device, characterized in that: Including the lithium ion battery according to claim 10.

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