Positive electrode material, positive electrode plate, preparation method of positive electrode plate, battery and electric device

Abstract

The invention discloses a positive electrode material, a positive electrode plate, a preparation method of the positive electrode plate, a battery and an electric device, and the preparation method of the positive electrode material comprises the following steps: dissolving an organic carbon source in a solvent R1 to prepare a solution A; dispersing a base material of the positive electrode material in the solution A, and stirring to obtain a turbid liquid B; soluble salt of metal Me is dissolved in a solvent R2, and a metal Me salt solution C is prepared; adding the metal Me salt solution C into the turbid liquid B, stirring and drying to obtain powder; and placing the powder in a furnace body, preserving heat for a preset time, and cooling to obtain the positive electrode material coated with the composite layer. According to the preparation method of the positive electrode material disclosed by the invention, the coating uniformity can be remarkably improved, so that each matrix material particle can be uniformly covered, and the electrochemical performance difference caused by non-uniform coating is avoided.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a positive electrode material, a positive electrode sheet and a preparation method thereof, a battery and an electrical device. Background Art

[0002] In related technologies, with the continuous advancement of science and technology, batteries have become an indispensable part of modern life, especially in many fields such as mobile phones, laptops, electric vehicles, etc. These batteries are favored for their high energy density, long life and environmental friendliness. However, with the deepening of applications, the requirements for battery performance are also getting higher and higher, especially in terms of the uniformity of the composite layer coating of the positive electrode material. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for preparing a positive electrode material, which can improve the uniformity of the composite layer coating.

[0004] The present invention also provides a positive electrode material, which is prepared by the preparation method of fir.

[0005] The present invention further provides a positive electrode plate, which includes a positive electrode active material layer formed by the above-mentioned positive electrode material.

[0006] The present invention also provides a method for preparing a positive electrode sheet, and the preparation method is applied to the above-mentioned positive electrode sheet.

[0007] The present invention also provides another method for preparing a positive electrode sheet, which is applied to the above-mentioned positive electrode sheet.

[0008] The present invention also provides a battery, comprising the above-mentioned positive electrode plate.

[0009] The present invention further provides an electrical device, which includes the battery mentioned above.

[0010] The method for preparing a positive electrode material according to an embodiment of the present invention comprises:

[0011] Dissolve the organic carbon source in solvent R1 to prepare solution A;

[0012] Dispersing the matrix material of the positive electrode material in solution A and stirring to obtain suspension B;

[0013] Dissolving a soluble salt of metal Me in solvent R2 to prepare a metal Me salt solution C;

[0014] Add metal Me salt solution C to suspension B, stir and dry to obtain powder;

[0015] The powder is placed in a furnace body, kept warm for a preset time, and then cooled to obtain a cathode material with a coated composite layer.

[0016] According to the method for preparing a cathode material of an embodiment of the present invention, the cathode material is prepared by a wet method. By dissolving an organic carbon source in a solvent R1, solution A is prepared. The matrix material of the cathode material is dispersed in solution A, and stirred to obtain suspension B. A soluble salt of metal Me is dissolved in a solvent R2 to prepare a metal Me salt solution C. The metal Me salt solution C is added to suspension B, heated, stirred, dried, and the solvent is evaporated to obtain a powder. Then, the powder is placed in a furnace body, kept warm for a preset time, and then cooled to obtain a cathode material with a coated composite layer, which can significantly improve the uniformity of coating, thereby ensuring that each matrix material particle can be evenly covered, and avoiding the electrochemical performance differences caused by uneven coating.

[0017] According to some embodiments of the present invention, the matrix material of the cathode material is a lithium-rich manganese material, and the molecular formula of the lithium-rich manganese material is Li 1+x Ni a Co b Mn c M d O2, where 0 < x < 0.5, 0.30 ≤ a ≤ 0.40, 0 ≤ b ≤ 0.10, 0.50 ≤ c ≤ 0.70, 0 ≤ d ≤ 0.1, and a + b + c + d = 1.

[0018] In some embodiments of the present invention, the specific surface area of the lithium-rich manganese material is 0.5 m 2 / g - 5 m 2 / g, the tapped density is 1.5 g / cm 3 -2.5 g / cm 3 The compaction density is 2.0 g / cm 3 -3.3 g / cm 3 The particle size D50 is 1 μm - 15 μm, and the size distribution K90 is ((D90 - D10) / D50) and is 0.2 - 2.0.

[0019] In some embodiments of the present invention, metal Me includes at least one of Al, Ba, Ce, Cr, Cu, Fe, K, La, Mg, Mo, Na, Nb, Ru, Sc, Sr, Ta, Ti, V, W, Y, Yb, Zn, and Zr.

[0020] According to some embodiments of the present invention, in solution A, the content of the organic carbon source is 1 wt% - 10 wt%; and / or, in solution C, the content of the metal Me salt is 1 wt% - 10 wt%.

[0021] According to some embodiments of the present invention, at least one of the solvent R1 and the solvent R2 includes at least one of water and ethanol.

[0022] According to some embodiments of the present invention, the organic carbon source includes at least one of carboxyl-containing organic acids, sugar-containing organic matter and organic polymers.

[0023] In some embodiments of the present invention, when the organic carbon source includes an organic acid containing a carboxyl group, the organic carbon source includes at least one of formic acid, acetic acid, propionic acid, and citric acid; and / or, when the organic carbon source includes a sugar organic matter, the organic carbon source includes at least one of sucrose and glucose; and / or, when the organic carbon source includes an organic polymer, the organic carbon source includes at least one of formic acid, acetic acid, oxalic acid, and propionic acid.

[0024] According to some embodiments of the present invention, in the suspension B, the mass ratio of the base material of the positive electrode material to the organic carbon source is 1:M, where M is 0.1-0.01.

[0025] According to some embodiments of the present invention, in the step of dispersing the matrix material of the positive electrode material in solution A and stirring to obtain suspension B, the stirring time is 10 min-60 min.

[0026] According to some embodiments of the present invention, the soluble salt of metal Me includes at least one of chloride, sulfide, hydroxide, phosphate, carbonate, organic acid salt and alkoxide of metal Me.

[0027] According to some embodiments of the present invention, in the step of adding the metal Me salt solution C to the suspension B, stirring and drying to obtain a powder, the drying method includes at least one of stirring and heating drying, flat plate heat drying, freeze drying and vacuum drying.

[0028] According to some embodiments of the present invention, in the step of adding the metal Me salt solution C to the suspension B, stirring and drying to obtain a powder, the drying temperature is 60° C.-100° C., and the drying time is 1 h-5 h.

[0029] According to some embodiments of the present invention, the step of placing the powder in a furnace body and keeping it warm for a preset time and then cooling it to obtain a positive electrode material coated with a composite layer includes: placing the powder in a tubular furnace, keeping it warm in a high-temperature inert atmosphere for a preset time, and then naturally cooling it to obtain a positive electrode material coated with a composite layer.

[0030] In some embodiments of the present invention, the inert atmosphere is argon, nitrogen or carbon dioxide.

[0031] According to some embodiments of the present invention, the furnace body and furnace chamber heating rate is 2°C / min-10°C / min, the heat treatment temperature is 300°C-700°C, and the insulation time is 2h-12h.

[0032] According to the positive electrode material of the embodiment of the present invention, the positive electrode material is prepared by the above-mentioned preparation method, and the positive electrode material includes: a base material; a composite layer, the composite layer is coated outside the base material and includes organic carbon and metal Me oxide.

[0033] According to the positive electrode material of the embodiment of the present invention, by coating the composite layer including organic carbon and metal oxide on the outside of the base material, it can not only effectively prevent the direct contact between the base material and the electrolyte, thereby inhibiting the corrosion of the electrolyte to the base material, but also enhance the structural stability of the material, which is helpful to improve the long cycle performance of the lithium-rich manganese positive electrode, but also improve the electronic conductivity of the lithium-rich manganese positive electrode material, reduce the internal resistance of the material, and improve the rate performance of the positive electrode material.

[0034] In some embodiments of the present invention, the coating content of the organic carbon is 0.1%-5%, and the content of the metal Me is 500ppm-5000ppm.

[0035] In some embodiments of the present invention, the composite layer has a thickness of 3nm-30nm.

[0036] The positive electrode sheet according to the embodiment of the present invention comprises: a positive electrode current collector; a positive electrode active material layer, wherein the positive electrode active material layer is arranged on one side of the positive electrode current collector in the thickness direction, and the positive electrode active material layer comprises the above-mentioned positive electrode material.

[0037] According to the positive electrode plate of the embodiment of the present invention, by providing a positive electrode active material layer including the above-mentioned positive electrode material, the performance of the positive electrode plate under high voltage and high current working conditions is ensured, so that the battery can maintain a high capacity and energy output under high rate charge and discharge conditions, meeting the needs of electric vehicles and mobile devices for fast charge and discharge capabilities.

[0038] According to the method for preparing a positive electrode sheet according to an embodiment of the present invention, the positive electrode sheet is the above-mentioned positive electrode sheet, and the method for preparing a positive electrode sheet includes:

[0039] The positive electrode material, the electronic conductive agent and the auxiliary agent are mixed in a preset ratio to form a slurry;

[0040] Applying the slurry on the positive electrode current collector according to a certain loading amount;

[0041] Drying the positive electrode current collector coated with the slurry;

[0042] The dried positive electrode current collector coated with the slurry is roll-pressed.

[0043] The method for preparing the positive electrode plate according to the embodiment of the present invention ensures the performance of the positive electrode plate under high voltage and high current working conditions, so that the battery can maintain a high capacity and energy output under high rate charge and discharge conditions, meeting the requirements of electric vehicles and mobile devices for fast charge and discharge capabilities.

[0044] According to the method for preparing a positive electrode sheet according to an embodiment of the present invention, the positive electrode sheet is the above-mentioned positive electrode sheet, and the method for preparing a positive electrode sheet includes:

[0045] Mixing the positive electrode material, the electronic conductive agent and the auxiliary agent according to a preset ratio;

[0046] Apply shear force to the mixed powder to fiberize the additive to obtain a blank;

[0047] Extruding or rolling the billet into a self-supporting film;

[0048] The self-supporting film is loaded onto a current collector that is rolled between two rollers and rolled to form a pole piece.

[0049] The method for preparing the positive electrode plate according to the embodiment of the present invention ensures the performance of the positive electrode plate under high voltage and high current working conditions, so that the battery can maintain a high capacity and energy output under high rate charge and discharge conditions, meeting the requirements of electric vehicles and mobile devices for fast charge and discharge capabilities.

[0050] The battery according to the embodiment of the present invention comprises a shell; an electrode group, which is arranged in the shell and comprises a positive electrode sheet and a negative electrode sheet which are stacked, and the positive electrode sheet is the positive electrode sheet mentioned above.

[0051] According to the battery of the embodiment of the present invention, by providing the above-mentioned positive electrode plate, the battery can maintain a relatively high capacity and energy output under high-rate charge and discharge conditions, thereby meeting the requirements of electric vehicles and mobile devices for fast charge and discharge capabilities.

[0052] An electric device according to an embodiment of the present invention includes the above-mentioned battery.

[0053] According to the power-consuming device of the embodiment of the present invention, by providing the above-mentioned battery, the battery can maintain a relatively high capacity and energy output under high-rate charge and discharge conditions, thereby meeting the requirements of electric vehicles and mobile devices for fast charge and discharge capabilities.

[0054] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0056] Figure 1 is a schematic diagram of a positive electrode material according to an embodiment of the present invention;

[0057] Figure 2 is an X-ray diffraction (XRD) pattern of the positive electrode material of Example 1;

[0058] Figure 3 is a scanning electron microscope (SEM) image of a conventional positive electrode material of Comparative Example 1;

[0059] Figure 4 is a scanning electron microscope (SEM) image of the positive electrode material of Example 2;

[0060] Figure 5 This is the Zr element energy dispersive spectrum analysis (EDS) spectrum of the positive electrode material of Example 3.

[0061] Reference numerals:

[0062] 100. Positive electrode material;

[0063] 1. Matrix material; 2. Metal oxide; 3. Organic carbon. DETAILED DESCRIPTION

[0064] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0065] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0066] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0067] Reference below Figure 1-Figure 5 A method for preparing the positive electrode material 100 according to an embodiment of the present invention is described.

[0068] The method for preparing the positive electrode material 100 according to an embodiment of the present invention includes:

[0069] Solution A is prepared by dissolving an organic carbon source in solvent R1.

[0070] The solvent R1 may include at least one of water and ethanol. For example, the solvent R1 may be water or ethanol. Of course, the solvent R1 may also be a mixed solution of water and ethanol.

[0071] The organic carbon source may include at least one of organic acids containing carboxyl groups, organic carbohydrates, and organic polymers. For example, the organic carbon source may include only organic acids containing carboxyl groups, or only organic carbohydrates, or only organic polymers, or any two of organic acids containing carboxyl groups, organic carbohydrates, and organic polymers, or all three of organic acids containing carboxyl groups, organic carbohydrates, and organic polymers.

[0072] In addition, when the organic carbon source includes an organic acid containing a carboxyl group, the organic carbon source includes at least one of formic acid, acetic acid, propionic acid, and citric acid; when the organic carbon source includes a sugar organic matter, the organic carbon source includes at least one of sucrose and glucose; when the organic carbon source includes an organic polymer, the organic carbon source includes at least one of formic acid, acetic acid, oxalic acid, and propionic acid. Specifically, the organic carbon source can be polyethylene glycol, polyvinyl alcohol, polyacrylic acid, and the like.

[0073] For example, when the solvent R1 is ethanol and the organic carbon source is acrylic acid, when preparing solution A, the acrylic acid can be dissolved in ethanol and stirred evenly to obtain solution A.

[0074] The base material 1 of the positive electrode material 100 is dispersed in the solution A and stirred to obtain a suspension B. The base material 1 of the positive electrode material 100 is dispersed in the solution A so that the base material 1 of the positive electrode material 100 is coated by the solution A.

[0075] Dissolving a soluble salt of metal Me in solvent R2 to prepare a metal Me salt solution C;

[0076] The solvent R2 may include at least one of water and ethanol. For example, the solvent R2 may be water or ethanol. Of course, the solvent R2 may also be a mixed solution of water and ethanol.

[0077] The soluble salt of metal Me includes at least one of chloride, sulfide, hydroxide, phosphate, carbonate, organic acid salt and alkoxide of metal Me. For example, the soluble salt of metal Me includes a mixture of one or more of chloride, sulfide, hydroxide, phosphate, carbonate, organic acid salt and alkoxide of metal Me. Metal Me includes at least one of Al, Ba, Ce, Cr, Cu, Fe, K, La, Mg, Mo, Na, Nb, Ru, Sc, Sr, Ta, Ti, V, W, Y, Yb, Zn and Zr.

[0078] For example, when the solvent R2 is ethanol and the soluble salt of metal Me is zirconium n-propoxide, when preparing the metal Me salt solution C, the zirconium n-propoxide solution is added to the ethanol and stirred evenly to obtain the metal Me salt solution C.

[0079] Add metal Me salt solution C into suspension B, stir and dry to obtain powder.

[0080] Among them, before adding the metal Me salt solution C to the suspension B, the suspension B is continuously stirred to ensure the uniform distribution of the matrix material 1 and solution A of the positive electrode material 100. After adding the metal Me salt solution C to the suspension B, it is also continuously stirred to ensure the uniform distribution of the matrix material 1, solution A and solution C of the positive electrode material 100, so that A and solution C can evenly coat the matrix material 1 of the positive electrode material 100.

[0081] The powder is placed in a furnace for a preset time and then cooled to obtain the positive electrode material 100 coated with the composite layer. In addition, the cooled product can be crushed or ground.

[0082] The obtained positive electrode material 100 includes a base material 1 and a composite layer, wherein the composite layer is coated on the outside of the base material 1 and includes organic carbon 3 and an oxide of metal Me. The organic carbon 3 is formed by an organic carbon source in solution A, and the oxide of metal Me is formed by a soluble salt of metal Me in a metal Me salt solution.

[0083] Due to its stable chemical properties, the protective film formed by the metal oxide 2 on the surface of the base material 1 can effectively isolate the direct contact between the base material 1 and the electrolyte, effectively inhibit the side reaction between the surface of the base material 1 and the electrolyte, reduce the corrosion of the electrolyte to the base material 1 and the dissolution of the transition metal, not only enhance the structural stability of the material, but also help maintain the performance of the battery during long-term operation, thereby improving the cycle stability and safety of the battery. In addition, the organic carbon 3 coating layer not only improves the electronic conductivity of the base material 1, not only can it reduce the internal resistance of the base material 1, but also can increase the migration rate of lithium ions, and also improves the shortcomings of the positive electrode material 100 such as poor rate performance and poor cycle performance, thereby significantly improving the rate performance of the positive electrode material 100. This improvement enables the battery to maintain a high capacity and energy output under high rate charge and discharge conditions, meeting the needs of electric vehicles and mobile devices for fast charge and discharge capabilities.

[0084] In addition, the composite coating of metal oxide 2 and organic carbon 3 combines the advantages of both and provides more comprehensive protection. This composite coating can not only prevent the corrosion of the electrolyte to the material, but also improve the electrical conductivity and ion migration rate of the material. Therefore, the synergistic protection of the composite layer, while improving the long cycle life of the base material 1, also ensures the performance of the material under high rate conditions, such as ensuring the performance of the material under high voltage and high current working conditions, and optimizes the performance of the positive electrode material 100, providing important technical support for the development of a new generation of high-performance and high-safety lithium-ion batteries. In addition, the composite coating can also effectively buffer the volume expansion and contraction of the positive electrode material 100 during the charging and discharging process, reduce structural stress, thereby reducing the risk of material breakage and shedding, and further improving the cycle stability and safety of the battery.

[0085] In the related technology, Na2S2O8 is selected to introduce a spinel structure on the surface of the lithium-rich manganese positive electrode material, and the surface is carbon-coated at the same time. Although the positive electrode material optimized by this method can improve the ionic and electronic conductivity and enhance the rate performance of the material, the traditional dry mixed sintering method of coating has the disadvantages of uniformity problems and uncontrollable coating thickness. Moreover, since dry coating relies on physical mixing and friction, the coating layer is too thick or too thin, making it difficult to achieve uniform surface modification of the positive electrode material, resulting in reduced cycle stability and inconsistent battery performance.

[0086] In other related technologies, an olivine-type structured LiMnPO4 is coated on the surface of a lithium-rich manganese positive electrode material by a sol-gel method. The coating layer can effectively improve the cycle stability of the positive electrode material and inhibit the voltage drop of the material during the cycle. However, this method is a single LiMnPO4 coating modification technology. LiMnPO4 with low ion conductivity will suppress the rate performance of the positive electrode material, and the sol-gel method is only applicable to laboratories. It may face challenges in large-scale production and requires fine control of reaction conditions to maintain the consistency of the product. Alternatively, a dense silica coating layer is formed on the surface of a lithium-rich manganese-based positive electrode material and its precursor by hydrolysis of tetraethyl orthosilicate. The coating layer can effectively block the contact between the positive electrode material and the electrolyte, inhibit the decomposition of the electrolyte, and improve the cycle stability of the lithium-rich manganese positive electrode material. However, the electronic conductivity of the silica coating layer is poor, and the dense coating layer will reduce the rate performance of the material.

[0087] In view of the problems of non-uniformity and uncontrollable thickness of traditional dry mixed coating, as well as the low conductivity and uneven distribution of the coating layer, which in turn affect the rate performance and long cycle life of lithium-rich manganese positive electrode materials, the preparation method of the present invention is provided. By adopting wet coating technology, a composite coating layer of metal oxide 2 and organic carbon 3 is introduced on the surface of the base material 1. Compared with traditional dry coating, wet coating technology can significantly improve the uniformity of coating, thereby ensuring that each particle of the base material 1 can be evenly covered, avoiding the difference in electrochemical performance caused by uneven coating.

[0088] According to the preparation method of the positive electrode material 100 of the embodiment of the present invention, the positive electrode material 100 is prepared by a wet method, by dissolving an organic carbon source in a solvent R1 to prepare a solution A, dispersing the base material 1 of the positive electrode material 100 in the solution A, stirring to obtain a suspension B, dissolving a soluble salt of metal Me in a solvent R2, preparing a metal Me salt solution C, adding the metal Me salt solution C to the suspension B, heating, stirring, drying and evaporating the solvent to obtain a powder, and then placing the powder in a furnace to keep warm for a preset time and then cooling to obtain the positive electrode material 100 coated with a composite layer, which can significantly improve the uniformity of the coating, thereby ensuring that each particle of the base material 1 can be evenly covered, avoiding differences in electrochemical performance caused by uneven coating.

[0089] In some embodiments of the present invention, the base material 1 of the positive electrode material 100 is a lithium-rich manganese material, and the molecular formula of the lithium-rich manganese material is Li 1+x Ni a Co b Mn c M dO2, where 0 < x < 0.5, 0.30 ≤ a ≤ 0.40, 0 ≤ b ≤ 0.10, 0.50 ≤ c ≤ 0.70, 0 ≤ d ≤ 0.1, and a + b + c + d = 1. The lithium-rich manganese material has the advantages of high specific capacity, high voltage, and low cost. Its discharge specific capacity can exceed 250 mAh / g, making it an important candidate material for high-energy-density lithium batteries. For the fields of electric vehicles and mobile devices, developing lithium-rich manganese materials that not only have high energy density but also meet the requirements of long-term cyclic use is crucial for achieving the dual goals of high endurance and cost-effectiveness. For example, the molecular formula of the lithium-rich manganese material can be Li 1.23 Ni 0.13 Co 0.13 Mn 0.51 O2.

[0090] In some embodiments of the present invention, the specific surface area of the lithium-rich manganese material is 0.5 m 2 / g - 5 m 2 / g, the tap density is 1.5 g / cm 3 - 2.5 g / cm 3 , the compaction density is 2.0 g / cm 3 - 3.3 g / cm 3 , the particle size D50 is 1 μm - 15 μm, and the size distribution K90 is ((D90 - D10) / D50) and is 0.2 - 2.0. Among them, D10 refers to the particle size corresponding to when the cumulative volume percentage of the positive electrode active material reaches 10%, D90 refers to the particle size corresponding to when the cumulative volume percentage of the positive electrode active material reaches 90%, and D50 refers to the particle size corresponding to when the cumulative volume percentage of the positive electrode active material reaches 50%.

[0091] In some embodiments of the present invention, in solution A, the content of the organic carbon source is 1 wt% - 10 wt%. For example, in solution A, the content of the organic carbon source can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%. This can ensure that sufficient organic carbon 3 is coated on the matrix material 1 of the positive electrode material 100, which not only improves the electronic conductivity of the matrix material 1, not only can reduce the internal resistance of the matrix material 1, but also can increase the migration rate of lithium ions, and also improves the disadvantages such as poor rate performance and poor cycle performance of the positive electrode material 100, thereby significantly improving the rate performance of the positive electrode material 100.

[0092] In some embodiments of the present invention, in solution C, the content of metal Me salt is 1wt%-10wt%. For example, in solution C, the content of metal Me salt can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%. In this way, it can be ensured that the base material 1 of the positive electrode material 100 is coated with enough metal oxide 2, and the protective film formed on the surface of the base material 1 can effectively isolate the direct contact between the base material 1 and the electrolyte, effectively inhibit the side reaction between the surface of the base material 1 and the electrolyte, reduce the corrosion of the electrolyte to the base material 1 and the dissolution of the transition metal, not only enhance the structural stability of the material, but also help to maintain the performance of the battery during long-term operation, thereby improving the cycle stability and safety of the battery.

[0093] In some embodiments of the present invention, in the suspension B, the mass ratio of the base material 1 of the positive electrode material 100 to the organic carbon source is 1:M, and M is 0.1-0.01. For example, the mass ratio of the base material 1 of the positive electrode material 100 to the organic carbon source can be 1:0.1, 1:0.0.09, 1:0.08, 1:0.07, 1:0.06, 1:0.05, 1:0.04, 1:0.03, 1:0.02, 1:0.01. In this way, it can be ensured that the base material 1 of the positive electrode material 100 is coated with sufficient organic carbon 3, which not only improves the electronic conductivity of the base material 1, not only reduces the internal resistance of the base material 1, but also increases the migration rate of lithium ions, and also improves the shortcomings of the positive electrode material 100 such as poor rate performance and poor cycle performance, thereby significantly improving the rate performance of the positive electrode material 100.

[0094] In some embodiments of the present invention, the matrix material 1 of the positive electrode material 100 is dispersed in solution A and stirred to obtain suspension B, and the stirring time is 10 min-60 min. For example, the stirring time can be 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min. In this way, the matrix material 1 of the positive electrode material 100 can be fully dispersed in solution A, and the distribution of the matrix material 1 in the obtained suspension B is more uniform, so that the organic carbon 3 of the coating layer on the positive electrode material 100 obtained in the end is more uniform and has better consistency.

[0095] In some embodiments of the present invention, when the metal Me salt solution C is added to the suspension B, the powder is obtained by stirring and drying, and the drying method includes at least one of stirring and heating drying, plate heat drying, freeze drying and vacuum drying. For example, in the process of stirring and drying to obtain the powder, one of stirring and heating drying, plate heat drying, freeze drying and vacuum drying or multiple of them can be used at the same time.

[0096] In some embodiments of the present invention, when the metal Me salt solution C is added to the suspension B, the powder is obtained by stirring and drying, and the drying temperature is 60°C-100°C, and the drying time is 1h-5h. For example, the drying temperature can be 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, and the drying time can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h or 5h, etc.

[0097] It is understood that the lower the drying temperature, the longer the drying time, and the higher the drying temperature, the shorter the drying time.

[0098] In some embodiments of the present invention, the powder is placed in a furnace for a preset time and then cooled to obtain the positive electrode material 100 coated with the composite layer, which includes: placing the powder in a tubular furnace, and after being heated in a high-temperature inert atmosphere for a preset time, naturally cooling to obtain the positive electrode material 100 coated with the composite layer. The inert atmosphere is conducive to protecting the powder, and the inert gas has a good thermal insulation effect.

[0099] Optionally, the inert atmosphere is argon, nitrogen or carbon dioxide.

[0100] In some embodiments of the present invention, the furnace temperature rise rate is 2°C / min-10°C / min, the heat treatment temperature is 300°C-700°C, and the holding time is 2h-12h, thereby improving the drying effect of the powder and obtaining a positive electrode material 100 of higher quality.

[0101] Three methods for preparing the positive electrode material 100 according to embodiments of the present invention are described below.

[0102] Embodiment 1

[0103] (1) dissolving polyacrylic acid in ethanol and stirring evenly to prepare an organic carbon source solution A with a concentration of 0.5 wt %;

[0104] (2) 100 g of uncoated Li 1.23 Ni 0.13 Co 0.13 Mn 0.51 O2 matrix material 1 is mixed with 100g solution A, and stirred to obtain a uniform suspension B;

[0105] (3) adding 0.7695 g of 70% zirconium n-propoxide solution to 10 g of ethanol to prepare a metal salt solution C;

[0106] (4) Suspension B is continuously stirred, and salt solution C is added dropwise thereto, and stirring is continued for 30 min, followed by heating at 80° C. to dry the solvent to obtain a powder;

[0107] (5) The powder was placed in a tube furnace, heated to 600° C. at a rate of 5° C. / min in an argon atmosphere, and calcined for 6 h to obtain a composite coated modified lithium-rich manganese positive electrode material 100.

[0108] Embodiment 2

[0109] (1) dissolving polyacrylic acid in ethanol and stirring evenly to prepare an organic carbon source solution A with a concentration of 1 wt%;

[0110] (2) 100 g of uncoated Li 1.23 Ni 0.13 Co 0.13 Mn 0.51 100 g of O2 positive electrode material was mixed with 100 g of solution A, and stirred to obtain a uniform suspension B;

[0111] (3) adding 1.539 g of 70% zirconium n-propoxide solution to 10 g of ethanol to prepare metal salt solution C;

[0112] (4) Suspension B is continuously stirred, and salt solution C is added dropwise thereto, and stirring is continued for 30 min, followed by heating at 80° C. to dry the solvent to obtain a powder;

[0113] (5) The powder was placed in a tube furnace, heated to 600° C. at a rate of 5° C. / min in an argon atmosphere, and calcined for 6 h to obtain a composite coated modified lithium-rich manganese positive electrode material 100.

[0114] Embodiment 3

[0115] (1) dissolving polyacrylic acid in ethanol and stirring evenly to prepare an organic carbon source solution A with a concentration of 0.5 wt %;

[0116] (2) 100 g of uncoated Li 1.23 Ni 0.13 Co 0.13 Mn 0.51 100 g of O2 positive electrode material was mixed with 100 g of solution A, and stirred to obtain a uniform suspension B;

[0117] (3) adding 0.5130 g of 70% zirconium n-propoxide solution to 10 g of ethanol to prepare a metal salt solution C;

[0118] (4) Suspension B is continuously stirred, and salt solution C is added dropwise thereto, and stirring is continued for 30 min, followed by heating at 80° C. to dry the solvent to obtain a powder;

[0119] (5) The powder was placed in a tube furnace, heated to 600° C. at a rate of 5° C. / min in an argon atmosphere, and calcined for 6 h to obtain a composite coated modified lithium-rich manganese positive electrode material 100.

[0120] Figure 2 This is a spectrum obtained by X-ray diffraction (XRD) of the positive electrode material 100 of Example 1. The diffraction peak of this material is consistent with the peak position of common lithium-rich materials. The crystal structure is complete without impurity peaks and the peak shape is sharp, indicating that the composite coating modification will not damage the material structure. Figure 4 is the surface morphology of the positive electrode material 100 of Example 2 observed under a scanning electron microscope (SEM), and Figure 3 Compared with the surface morphology of the unmodified lithium-rich manganese-based material (the base material without a composite layer on the surface), the surface particles of the surface composite-coated material become smoother, and the gaps between the primary particles become smaller or even disappear, indicating that an obvious composite coating layer is formed on the surface of the modified lithium-rich manganese positive electrode material 100 (the positive electrode material 100 of the present application). Figure 5 1 is the EDS spectrum of the Zr element of the positive electrode material 100 of Example 3. It can be seen that the distribution of the Zr element on the surface of the lithium-manganese-rich positive electrode material 100 is relatively uniform.

[0121] Examples 1, 2 and 3 and the comparative example (with Li without surface coating treatment) 1.23 Ni 0.13 Co 0.13 Mn 0.51 The positive electrode material product in the liquid system (with O2 as the positive electrode active material) was assembled into a battery, and the electrochemical performance was tested in the test voltage range of 2-4.6V. The results are shown in Table 1.

[0122] Table 1

[0123]

[0124] The positive electrode material 100 according to an embodiment of the present invention is described below.

[0125] like Figure 1 As shown, the positive electrode material 100 according to the embodiment of the present invention is prepared by the above-mentioned preparation method, and the positive electrode material 100 includes a base material 1 and a composite layer.

[0126] The base material 1 can be a lithium-rich manganese material, and the composite layer is coated on the outside of the base material 1 and includes organic carbon 3 and oxides of metal Me. Among them, the metal oxide 2 can effectively prevent the direct contact between the base material 1 and the electrolyte, thereby inhibiting the corrosion of the electrolyte to the base material 1, enhancing the structural stability of the material, and helping to improve the long-cycle performance of the lithium-rich manganese positive electrode. The organic carbon 3 coating can improve the electronic conductivity of the lithium-rich manganese positive electrode material 100, reduce the internal resistance of the material, and improve the rate performance of the positive electrode material 100.

[0127] According to the positive electrode material 100 of the embodiment of the present invention, by coating the composite layer including organic carbon 3 and metal oxide 2 on the outside of the base material 1, it can not only effectively prevent the direct contact between the base material 1 and the electrolyte, thereby inhibiting the corrosion of the electrolyte to the base material 1, but also enhance the structural stability of the material, which is helpful to improve the long cycle performance of the lithium-rich manganese positive electrode, but also can improve the electronic conductivity of the lithium-rich manganese positive electrode material 100, can reduce the internal resistance of the material, and improve the rate performance of the positive electrode material 100.

[0128] In some embodiments of the present invention, the coating content of organic carbon 3 is 0.1%-5%, and the content of metal Me is 500ppm-5000ppm. For example, the coating content of organic carbon 3 can be 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, and the content of metal Me can be 500ppm, 600ppm, 700ppm, 800ppm, 900ppm, 1000ppm, 1300ppm, 1500ppm, 1700ppm, 2000ppm, 2300ppm, 2500ppm, 2700ppm, 3000ppm, 3300ppm, 3500ppm, 3700ppm, 3900ppm, 4000ppm, 4300ppm, 4500ppm, 4700ppm, 4900ppm or 5000ppm.

[0129] This can better prevent direct contact between the base material 1 and the electrolyte, thereby inhibiting the corrosion of the electrolyte on the base material 1, enhancing the structural stability of the material, helping to improve the long-cycle performance of the lithium-rich manganese positive electrode, and can improve the electronic conductivity of the lithium-rich manganese positive electrode material 100, which can reduce the internal resistance of the material and improve the rate performance of the positive electrode material 100.

[0130] In some embodiments of the present invention, the thickness of the composite layer is 3nm-30nm. For example, the thickness of the composite layer can be 5nm, 10nm, 15nm, 20nm, 25nm or 30nm. This can better prevent direct contact between the base material 1 and the electrolyte, thereby inhibiting the corrosion of the electrolyte to the base material 1, enhancing the structural stability of the material, helping to improve the long cycle performance of the lithium-rich manganese positive electrode, and can improve the electronic conductivity of the lithium-rich manganese positive electrode material 100, can reduce the internal resistance of the material, and improve the rate performance of the positive electrode material 100.

[0131] The following describes a positive electrode sheet according to an embodiment of the present invention.

[0132] The positive electrode sheet according to the embodiment of the present invention includes a positive electrode current collector and a positive polarity material layer. The positive electrode active material layer is arranged on one side of the positive electrode current collector in the thickness direction. The positive electrode active material layer includes the positive electrode material 100 described above.

[0133] According to the positive electrode plate of the embodiment of the present invention, by providing a positive electrode active material layer including the above-mentioned positive electrode material 100, the performance of the positive electrode plate under high voltage and high current working conditions is ensured, so that the battery can maintain a high capacity and energy output under high rate charge and discharge conditions, meeting the needs of electric vehicles and mobile devices for fast charge and discharge capabilities.

[0134] The following describes a method for preparing a positive electrode sheet according to an embodiment of the present invention.

[0135] Preparation method 1 (wet preparation)

[0136] The positive electrode material 100, the electronic conductive agent and the auxiliary agent are mixed in a preset ratio to form a slurry;

[0137] Applying the slurry on the positive electrode current collector according to a certain loading amount;

[0138] Drying the positive electrode current collector coated with the slurry;

[0139] The dried positive electrode current collector coated with the slurry is roll-pressed.

[0140] Preparation method 2 (binder fibrillation)

[0141] Mixing the positive electrode material 100, the electronic conductive agent and the auxiliary agent according to a preset ratio;

[0142] Apply shear force to the mixed powder to fiberize the additive to obtain a blank;

[0143] Extruding or rolling the billet into a self-supporting film;

[0144] The self-supporting film is loaded onto a current collector that is rolled between two rollers and rolled to form a pole piece.

[0145] The electronic conductive agent is selected from at least one of graphite, hard carbon, soft carbon, carbon nanotubes, graphene, porous carbon, superconducting carbon black (Super P), acetylene black (Acetylene Black), and furnace black (Furnace Black). The auxiliary agent is selected from one or more of polytetrafluoroethylene PTFE, polyvinylidene fluoride (PVDF), silicone rubber, styrene butadiene rubber (SBR), hydrogenated nitrile rubber (HNBR), boronated polyethylene glycol, cellulose, cellulose ester, cellulose ether, nitrocellulose, carboxyalkyl cellulose, cellulose salt, sodium carboxymethyl cellulose and cellulose salt derivatives, polyacrylic acid (PAA), polyamide (PAI), polyvinyl alcohol (PVA), polyethylene imine (PEI), and polyimide (PI).

[0146] The following describes a battery according to an embodiment of the present invention, wherein the battery may be a lithium-ion battery.

[0147] The battery according to the embodiment of the present invention comprises a housing and an electrode group. The electrode group is arranged in the housing and comprises a positive electrode sheet and a negative electrode sheet which are stacked. The positive electrode sheet is the above-mentioned positive electrode sheet.

[0148] The following describes a battery according to an embodiment of the present invention. By providing the above-mentioned positive electrode plate, the battery can maintain a high capacity and energy output under high-rate charge and discharge conditions, thereby meeting the requirements of electric vehicles and mobile devices for fast charge and discharge capabilities.

[0149] In some embodiments of the present invention, the battery is a soft-pack battery, a square-shell battery or a cylindrical battery.

[0150] In some embodiments of the present invention, the battery is a liquid battery, a semi-solid battery or an all-solid battery.

[0151] When the battery is a liquid battery, the battery comprises a positive electrode plate, a separator, an electrolyte and a negative electrode plate. The positive electrode plate is the positive electrode plate mentioned above.

[0152] The diaphragm material is one or more of polyethylene (PE), polypropylene (PP), polyimide (PI), polyamide-imide (PIA), and polyethylene terephthalate (PET).

[0153] The negative electrode plate also includes at least one of graphite, hard carbon, soft carbon, carbon nanotubes, graphene, porous carbon, superconducting carbon black (SuperP), acetylene black (Acetylene Black), furnace black (Furnace Black), metal lithium Li or metal lithium alloy Li-M. Among them, the metal lithium alloy Li-M can be an alloy formed by metal lithium and one or more of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, boron, silver, tin, silicon, carbon, phosphorus and the like, wherein the mass content of metal lithium is 1-99%.

[0154] The electrolyte comprises a lithium salt, a solvent and an additive; the solvent can be selected from carbonates (ethylene carbonate EC, propylene carbonate PC, butylene carbonate BC, dimethyl carbonate DMC, diethyl carbonate DEC, ethyl methyl carbonate EMC, -butyrolactone BL), ethers (tetrahydrofuran THF, 2-methyl-tetrahydrofuran 2-Me-THF, dimethoxydimethyl ether DMM, 1,2-dimethoxyethane DME, 1,3-dioxolane DOL), nitriles (acetonitrile AN, etc.), etc.; the lithium salt can be selected from lithium hexafluorophosphate LiPF6, lithium perchlorate LiClO4, lithium tetrafluoroborate LiBF4, lithium hexafluoroarsenate LiAsF6, other organic lithium salts (such as trifluoromethane The additives may include lithium trifluoromethylsulfonate LiCF3SO, lithium bis(trifluoromethylsulfonyl)imide LiTFSI, lithium bis(fluorosulfonyl)imide LiFSI, lithium trifluoromethylsulfonyl-perfluorobutylsulfonylimide LiTNFSI, lithium fluorosulfonyl-perfluorobutylsulfonylimide LiFNFSI, lithium bis(oxalatoborate) LiBOB, LiN(CF3SO2)2, LiC(SO2CF3)3, etc.; the additives may include film-forming additives, conductive additives, flame retardant additives, overcharge protection additives, additives for controlling the water and HF content in the electrolyte, general additives for improving low temperature performance, and additives for improving the interface stability between the electrode and the electrolyte, such as fluoroethylene carbonate FEC, etc.

[0155] The semi-solid battery comprises a positive electrode sheet, a gel electrolyte and a negative electrode sheet. The positive electrode sheet is the positive electrode sheet mentioned above in this solution.

[0156] The gel electrolyte is composed of a polymer and an electrolyte; the polymer is selected from one or more of polyethylene oxide (PEO), polyacrylate (PMMA), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polysiloxane (Siloxanes), polyethylene glycol (PEG), sodium polystyrene sulfonate (PSS), polyvinyl cyanide (PAN), polysulfone (PSU), and polyether sulfone (PES).

[0157] The electrolyte comprises a lithium salt, a solvent and an additive; the solvent can be selected from carbonates (ethylene carbonate EC, propylene carbonate PC, butylene carbonate BC, dimethyl carbonate DMC, diethyl carbonate DEC, ethyl methyl carbonate EMC, -butyrolactone BL), ethers (tetrahydrofuran THF, 2-methyl-tetrahydrofuran 2-Me-THF, dimethoxydimethyl ether DMM, 1,2-dimethoxyethane DME, 1,3-dioxolane DOL), nitriles (acetonitrile AN, etc.), etc.; the lithium salt can be selected from lithium hexafluorophosphate LiPF6, lithium perchlorate LiClO4, lithium tetrafluoroborate LiBF4, lithium hexafluoroarsenate LiAsF6, other organic lithium salts (such as trifluoromethane The additives may include lithium trifluoromethylsulfonate LiCF3SO, lithium bis(trifluoromethylsulfonyl)imide LiTFSI, lithium bis(fluorosulfonyl)imide LiFSI, lithium trifluoromethylsulfonyl-perfluorobutylsulfonylimide LiTNFSI, lithium fluorosulfonyl-perfluorobutylsulfonylimide LiFNFSI, lithium bis(oxalatoborate) LiBOB, LiN(CF3SO2)2, LiC(SO2CF3)3, etc.; the additives may include film-forming additives, conductive additives, flame retardant additives, overcharge protection additives, additives for controlling the water and HF content in the electrolyte, general additives for improving low temperature performance, and additives for improving the interface stability between the electrode and the electrolyte, such as fluoroethylene carbonate FEC, etc.

[0158] The all-solid-state battery comprises a positive electrode sheet, a solid electrolyte and a negative electrode sheet. The positive electrode sheet is the positive electrode sheet mentioned above in this solution.

[0159] The solid electrolyte layer includes one or more of an oxide electrolyte layer, a sulfide electrolyte layer, a halide electrolyte layer, a polymer electrolyte layer or a polymer-inorganic composite solid electrolyte layer.

[0160] The oxide solid electrolyte is selected from one or more of NASICON structure materials, perovskite structure materials, antiperovskite structure materials, LISICON structure materials and garnet structure materials.

[0161] The sulfide solid electrolyte is selected from the sulfide Li2S-P2S5, Li 10 GeP2S12, Li3PS4, Li 6- x PS 5-x Cl 1+x , the value range of x is: 0≤x≤0.8.

[0162] The general formula of the halide solid electrolyte material is: Li a (M b )X c X' d, wherein Li is a lithium ion, M represents one or more of Ga, Y, In, Mg, Sr, Sc, Sn, Pb, Ti, Zr, Hf, Nb, Ta, W, Fe, Ru, Al, and lanthanide metal elements, X includes any one of the halogen elements, and X' represents a halogen ion, a nitrogen ion, or an oxygen ion; 0.5≤a≤5, 0.2≤b≤4, c+d=a+bε, wherein ε is the weighted average valence of the M element.

[0163] The polymer electrolyte layer comprises a polymer and a lithium salt, wherein the polymer is selected from one or more of polyethylene oxide (PEO), polyacrylate (PMMA), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polysiloxanes, polyethylene glycol (PEG), sodium polystyrene sulfonate (PSS), polyvinyl cyanide (PAN), polysulfone (PSU), and polyether sulfone (PES). The lithium salt can be selected from one or more of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium hexafluoroarsenate, and other organic lithium salts, such as lithium trifluoromethyl sulfonate, lithium bis(trifluoromethylsulfonyl)imide, bis(trifluoromethylsulfonyl)imide, lithium trifluoromethylsulfonyl-perfluorobutylsulfonylimide, lithium fluorosulfonyl-perfluorobutylsulfonylimide, and lithium bis(oxalatoborate).

[0164] An electric device according to an embodiment of the present invention includes the above-mentioned battery.

[0165] According to the power-consuming device of the embodiment of the present invention, by providing the above-mentioned battery, the battery can maintain a relatively high capacity and energy output under high-rate charge and discharge conditions, thereby meeting the requirements of electric vehicles and mobile devices for fast charge and discharge capabilities.

[0166] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0167] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for preparing a positive electrode material, characterized in that: include: Dissolve the organic carbon source in solvent R1 to prepare solution A; Dispersing the matrix material of the positive electrode material in solution A and stirring to obtain suspension B; Dissolving a soluble salt of metal Me in solvent R2 to prepare a metal Me salt solution C; Add metal Me salt solution C to suspension B, stir and dry to obtain powder; The powder is placed in a furnace and kept warm for a preset time, and then cooled to obtain a positive electrode material coated with a composite layer.

2. The method for preparing the positive electrode material according to claim 1, characterized in that: The matrix material of the positive electrode material is a lithium-rich manganese material, and the molecular formula of the lithium-rich manganese material is Li 1+x Ni a Co b Mn c M d O2, where 0 < x < 0.5, 0.30 ≤ a ≤ 0.40, 0 ≤ b ≤ 0.10, 0.50 ≤ c ≤ 0.70, 0 ≤ d ≤ 0.1, and a + b + c + d = 1.

3. The method for preparing the positive electrode material according to claim 2, characterized in that: The specific surface area of ​​the lithium-rich manganese material is 0.5 m 2 / g-5m 2 / g, tap density is 1.5g / cm 3 -2.5g / cm 3 , compacted density is 2.0g / cm 3 -3.3g / cm 3 , the particle size D50 is 1 μm-15 μm, and the size distribution K90 is ((D90-D10) / D50) and is 0.2-2.

0.

4. The method for preparing the positive electrode material according to claim 2, characterized in that: The metal Me includes at least one of Al, Ba, Ce, Cr, Cu, Fe, K, La, Mg, Mo, Na, Nb, Ru, Sc, Sr, Ta, Ti, V, W, Y, Yb, Zn and Zr.

5. The method for preparing the positive electrode material according to claim 1, characterized in that: In the solution A, the content of the organic carbon source is 1wt%-10wt%; And / or, in the solution C, the content of the metal Me salt is 1wt%-10wt%.

6. The method for preparing the positive electrode material according to claim 1, characterized in that: At least one of the solvent R1 and the solvent R2 includes at least one of water and ethanol.

7. The method for preparing the positive electrode material according to claim 1, characterized in that: The organic carbon source includes at least one of carboxyl-containing organic acids, sugar-containing organic matter and organic polymers.

8. The method for preparing the positive electrode material according to claim 7, characterized in that: When the organic carbon source includes a carboxyl-containing organic acid, the organic carbon source includes at least one of formic acid, acetic acid, propionic acid, and citric acid; and / or, when the organic carbon source comprises a sugar organic matter, the organic carbon source comprises at least one of sucrose and glucose; And / or, when the organic carbon source includes an organic polymer, the organic carbon source includes at least one of formic acid, acetic acid, oxalic acid, and propionic acid.

9. The method for preparing the positive electrode material according to claim 1, characterized in that: In the suspension B, the mass ratio of the base material of the positive electrode material to the organic carbon source is 1:M, where M is 0.1-0.

01.

10. The method for preparing the positive electrode material according to claim 1, characterized in that: In the above, the base material of the positive electrode material is dispersed in the solution A, and stirred to obtain the suspension B, and the stirring time is 10min-60min.

11. The method for preparing the positive electrode material according to claim 1, characterized in that: The soluble salt of metal Me includes at least one of chloride, sulfide, hydroxide, phosphate, carbonate, organic acid salt and alkoxide of metal Me.

12. The method for preparing the positive electrode material according to claim 1, characterized in that: In the step of adding the metal Me salt solution C to the suspension B, stirring and drying to obtain a powder, the drying method includes at least one of stirring and heating drying, flat plate heat drying, freeze drying and vacuum drying.

13. The method for preparing the positive electrode material according to claim 1, characterized in that: In the step of adding the metal Me salt solution C to the suspension B, stirring and drying to obtain a powder, the drying temperature is 60° C.-100° C., and the drying time is 1 h-5 h.

14. The method for preparing a positive electrode material according to claim 1, characterized in that: The positive electrode material coated with the composite layer by placing the powder in a furnace for a preset time and then cooling it to obtain the positive electrode material comprises: The powder is placed in a tube furnace, kept warm in a high-temperature inert atmosphere for a preset time, and then cooled naturally to obtain a positive electrode material coated with a composite layer.

15. The method for preparing the positive electrode material according to claim 14, characterized in that: The inert atmosphere is argon, nitrogen or carbon dioxide.

16. The method for preparing a positive electrode material according to claim 1, characterized in that: The furnace body and furnace chamber heating rate is 2°C / min-10°C / min, the heat treatment temperature is 300°C-700°C, and the insulation time is 2h-12h.

17. A positive electrode material, characterized in that: The positive electrode material is prepared by the preparation method according to any one of claims 1 to 16, and the positive electrode material comprises: Base material; The composite layer is coated on the outside of the base material and includes organic carbon and oxide of metal Me.

18. The positive electrode material according to claim 17, characterized in that The coating content of the organic carbon is 0.1%-5%, and the content of the metal Me is 500ppm-5000ppm.

19. The positive electrode material according to claim 17, characterized in that The composite layer has a thickness of 3nm-30nm.

20. A positive electrode sheet, characterized in that: include: Positive electrode current collector; A positive electrode active material layer, wherein the positive electrode active material layer is disposed on one side of the positive electrode current collector in a thickness direction, and the positive electrode active material layer comprises the positive electrode material according to any one of claims 17 to 19.

21. A method for preparing a positive electrode sheet, characterized in that: The positive electrode sheet is the positive electrode sheet according to claim 20, and the preparation method of the positive electrode sheet comprises: The positive electrode material, the electronic conductive agent and the auxiliary agent are mixed in a preset ratio to form a slurry; Applying the slurry on the positive electrode current collector according to a certain loading amount; Drying the positive electrode current collector coated with the slurry; The dried positive electrode current collector coated with the slurry is roll-pressed.

22. A method for preparing a positive electrode sheet, characterized in that: The positive electrode sheet is the positive electrode sheet according to claim 20, and the preparation method of the positive electrode sheet comprises: Mixing the positive electrode material, the electronic conductive agent and the auxiliary agent according to a preset ratio; Apply shear force to the mixed powder to fiberize the additive to obtain a blank; Extruding or rolling the billet into a self-supporting film; The self-supporting film is loaded onto a current collector that is rolled between two rollers and rolled to form a pole piece.

23. A battery, characterized in that: include: case; The electrode group is arranged in the shell and includes a positive electrode sheet and a negative electrode sheet that are stacked, and the positive electrode sheet is the positive electrode sheet according to claim 20.

24. An electrical device, characterized in that: Comprising a battery according to claim 23.

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