Precursor material and preparation method thereof, positive electrode material and preparation method thereof, positive electrode plate, battery and electric device

Abstract

The invention provides a precursor material, a preparation method of the precursor material, a positive electrode material, a preparation method of the positive electrode material, a positive electrode plate, a battery and an electric device. The precursor material provided by the invention comprises a compound Mn < x > Fe < y > M < (1-x-y) > HPO < 4 >. NH < 2 > O, wherein x is greater than or equal to 0.9 and less than or equal to ytt; 0 < x < = 0.9, 0 < y < = 0.9, and 0 < = n < = 6; m comprises one or more of transition metal elements except manganese and iron elements, IIA group metal elements, IIIA group metal elements and IVA group metal elements. The elements in the precursor material are uniformly distributed, the batch consistency is good, the elements in the prepared positive electrode material are uniformly distributed, the batch consistency is good, and the specific capacity and the cycle performance of the battery are improved.

Description

Technical Field

[0001] The present application relates to the technical field of lithium batteries, and particularly to a precursor material, a preparation method of the precursor material, a cathode material, a preparation method of the cathode material, a cathode electrode sheet, a battery, and an electrical device. Background Art

[0002] In recent years, with the increasingly wide application scope of secondary batteries, secondary batteries are widely used in energy storage power systems such as hydraulic power stations, thermal power stations, wind power stations, and solar power stations, as well as in multiple fields such as electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, and aerospace. Due to the great development of secondary batteries, higher requirements are also put forward for their energy density, cycle performance, etc. Summary of the Invention

[0003] The present application is made in view of the above problems, and its purpose is to provide a precursor material, a preparation method of the precursor material, a cathode material, a preparation method of the cathode material, a cathode electrode sheet, a battery, and an electrical device. The elements in the precursor material of the present application are evenly distributed and have good batch consistency. The elements in the cathode material prepared by using the precursor material of the present application are evenly distributed and have good batch consistency, thereby improving the specific capacity and cycle performance of the prepared battery.

[0004] To achieve the above object, a first aspect of the present application provides a precursor material, including a compound Mn x Fe y M (1-x-y) HPO 4 ·nH 2 O; wherein, 0.9 ≤ x + y < 1, 0 < x ≤ 0.9, 0 < y ≤ 0.9, 0 ≤ n ≤ 6; the M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements.

[0005] The manganese, iron, phosphorus, and doping elements in the precursor material of the present application are evenly distributed and have good batch consistency. The elements in the cathode material prepared by using the precursor material of the present application are evenly distributed and have good batch consistency, thereby improving the electrical properties such as the specific capacity and cycle performance of the prepared battery.

[0006] In any embodiment, 0.992 ≤ x + y < 0.995; and / or, 0.513 ≤ x ≤ 0.658; and / or, 0.336 ≤ y ≤ 0.479; and / or, 0 ≤ n ≤ 1.

[0007] In any embodiment, the M includes one or more elements such as titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium.

[0008] In any embodiment, the Dv50 particle size of the precursor material is 3 - 100 μm, optionally 5 - 50 μm, more optionally 8 - 20 μm; and / or,

[0009] the compaction density of the precursor material at 30 MPa is 1.35 - 2.5 g / cm 3 ; and / or,

[0010] the compound Mn x Fe y M (1-x-y) HPO 4 ·nH 2 O in the precursor material has a mass content of 98% - 100%; and / or,

[0011] the precursor material includes primary crystallization particles with a polyhedral morphology.

[0012] With the Dv50 particle size of the precursor material of the present application within the above range, on the one hand, it is beneficial to the washing and filtration operations during the preparation of the precursor, improving the yield of the precursor material. On the other hand, when preparing the cathode material, it is beneficial for the suspension of the precursor particles and not easy to settle, thereby improving the efficiency of the mixing and grinding processes.

[0013] With the compaction density of the precursor material of the present application within the above range, it is beneficial to improve the compaction density of the cathode material, thereby enhancing the specific capacity of the battery.

[0014] The precursor material of the present application has a high compound content and a low impurity content, so that the impurity content of the prepared cathode material is low, and the specific capacity and cycle performance of the battery are improved.

[0015] The precursor material of the present application includes primary crystallization particles with a polyhedral morphology, whose crystal planes are flat and regular, and the particle gaps are smaller, which is beneficial to improving the compaction density of the precursor material.

[0016] The second aspect of the present application also provides a method for preparing a precursor material, including the following steps:

[0017] Dissolve a soluble manganese source, a soluble iron source and a source of soluble M element in a solvent to obtain a solution;

[0018] Slowly add the solution to a phosphoric acid solution for reaction, and obtain a reaction product after optional aging;

[0019] Filter the reaction product and dry the obtained filter residue to obtain the precursor material;

[0020] The precursor material includes the compound Mn x Fe y M (1-x-y) HPO 4·nH 2 O; wherein, 0.9 ≤ x + y < 1, 0 < x ≤ 0.9, 0 < y ≤ 0.9, 0 ≤ n ≤ 6; the M element includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, and may be selected from one or more of titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium.

[0021] Thus, in the present application, a soluble manganese source, a soluble iron source, and a source of soluble M element are first formulated into a stable and homogeneous solution, and then the solution is slowly added to a phosphoric acid solution to control and reduce side reactions, and then the filtered residue is optionally aged and dried to obtain a precursor material with uniform composition, good batch consistency, and low impurity content. The elements in the cathode material prepared using this precursor material are evenly distributed and have good batch consistency, thereby improving the specific capacity and cycling performance of the battery.

[0022] In any embodiment, the soluble manganese source includes one or more of a soluble organic manganese source and a soluble inorganic manganese source, may be a soluble organic manganese source, more preferably one or more of soluble organic acid salts of manganese, and further preferably one or more of manganous acetate, manganous formate, manganous citrate, and manganous 2-hydroxypropionate; and / or,

[0023] The soluble iron source includes one or more of a soluble organic iron source and a soluble inorganic iron source, may be a soluble organic iron source, more preferably one or more of soluble organic acid salts of iron, and further preferably one or more of ferrous acetate, ferrous formate, ferrous citrate, and ferrous 2-hydroxypropionate; and / or,

[0024] The source of soluble M element includes one or more of an inorganic source of soluble M element and an organic source of soluble M element, may be one or more of soluble organic acid salts and soluble inorganic acid salts of M element, and more preferably one or more of sulfates, nitrates, chlorides, formates, acetates, citrates, and 2-hydroxypropionates of M element.

[0025] Among them, the use of a soluble organic manganese source and / or a soluble organic iron source is beneficial to reducing the impurity content in the precursor material, improving the batch consistency, and thereby improving the specific capacity and cycling performance of the battery.

[0026] In any embodiment, at 25°C - 95°C, the solution is slowly added to the phosphoric acid solution for reaction; and / or,

[0027] The feeding time of the solution is 10 - 300 min, may be 15 - 300 min, and more preferably 60 - 180 min; and / or,

[0028] The molar ratio of phosphoric acid in the phosphoric acid solution to the total metal elements in the solution is 0.4 - 1.5, optionally 0.5 - 1.5, more optionally 0.8 - 1.2; and / or,

[0029] The total concentration of metal elements in the solution is 0.1 - 3.0 mol / L, optionally 0.5 - 2.5 mol / L, more optionally 1.0 - 2.0 mol / L; and / or,

[0030] The concentration of phosphoric acid in the phosphoric acid solution is 0.1 - 3.0 mol / L, optionally 0.5 - 2.5 mol / L, more optionally 1.0 - 2.0 mol / L; and / or,

[0031] The molar amount of element M in the solution accounts for 0.1% - 10% of the total molar amount of metal elements; and / or,

[0032] The molar amount of Mn element in the solution accounts for 30% - 85% of the total molar amount of metal elements.

[0033] In this application, by controlling the ambient temperature when adding the mixed metal solution to the phosphoric acid solution, side reactions can be reduced to obtain a precursor material with uniform composition, good batch consistency, and low impurity content, thereby improving the specific capacity and cycle performance of the battery.

[0034] In this application, by controlling the rate of adding the solution to the phosphoric acid solution, it is beneficial to control and reduce side reactions, and prepare a precursor material with uniform composition, good batch consistency, and low impurity content, thereby improving the electrical performance of the battery.

[0035] In this application, by controlling the molar ratio of phosphoric acid to total metal elements, the specific capacity of the battery can be improved.

[0036] In this application, by controlling the concentration of each metal element in the solution, the molar ratio of each metal element in the precursor product can be adjusted.

[0037] In any embodiment, the aging temperature is 40°C - 98°C; and / or,

[0038] The aging time is 10 - 500 min; and / or,

[0039] The reaction and / or aging is carried out under the condition that the pH value is 1.5 - 4.5; and / or,

[0040] The reaction and / or aging is carried out under stirring conditions.

[0041] Aging is beneficial for the crystallization and growth of precipitates, to reduce the proportion of amorphous particles in the precursor material, thereby obtaining a precursor material with better crystallinity and higher tap density, and thus improving the specific capacity and cycle performance of the battery.

[0042] In any embodiment, the dissolution is carried out at 25°C - 80°C; and / or,

[0043] The solvent is water; and / or,

[0044] The filtration is carried out by negative pressure suction filtration, positive pressure filtration or centrifugal filtration; and / or,

[0045] Before drying, the filter residue is washed, optionally washed with water; and / or,

[0046] The drying temperature is 80°C - 500°C, optionally 120°C - 400°C, more optionally 150°C - 300°C; and / or,

[0047] The drying time is 10 - 300 min.

[0048] The third aspect of the present application provides a cathode material, comprising a compound LiMn x Fe y M (1-x-y) PO 4 , where 0.9 ≤ x + y < 1, 0 < x ≤ 0.9, 0 < y ≤ 0.9, and M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, optionally including one or more elements of titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, europium;

[0049] Moreover, the raw materials for preparing the cathode material include the precursor material of the first aspect of the present application or the precursor material prepared by the method of the second aspect of the present application.

[0050] The fourth aspect of the present application provides a cathode material, comprising a core and a coating layer; the core comprises the compound LiMn x Fe y M (1-x-y) PO 4 ; where 0.9 ≤ x + y < 1, 0 < x ≤ 0.9, 0 < y ≤ 0.9, and M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, optionally including one or more elements of titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, europium; the coating layer comprises carbon;

[0051] Moreover, the raw materials for preparing the cathode material include the precursor material of the first aspect of the present application or the precursor material prepared by the method of the second aspect of the present application.

[0052] Therefore, the molar ratios of manganese, iron, doping element, and phosphorus elements in the precursor material of the present application are the same as those in the cathode material. As a result, the types of raw materials are reduced during the preparation of the cathode material, thereby improving the compositional uniformity and batch consistency of the cathode material, and enhancing the specific capacity and cycling performance of the battery.

[0053] The fifth aspect of the present application provides a method for preparing a cathode material, including the following steps:

[0054] Mix the precursor material of the first aspect of the present application or the precursor material prepared by the method of the second aspect of the present application and a lithium source in a solvent, grind, dry, and sinter to obtain the cathode material;

[0055] Among them, the cathode material includes the compound LiMn x Fe y M (1-x-y) PO 4 , where 0.9 ≤ x + y < 1, 0 < x ≤ 0.9, 0 < y ≤ 0.9, and M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, and may be selected from one or more of titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium.

[0056] The sixth aspect of the present application provides a method for preparing a cathode material, including the following steps:

[0057] Mix the precursor material of the first aspect of the present application or the precursor material prepared by the method of the second aspect of the present application, a lithium source, and a carbon source in a solvent, grind, dry, and sinter to obtain the cathode material;

[0058] Among them, the cathode material includes a core and a coating layer; the core includes the compound LiMn x Fe y M (1-x-y) PO 4 ; where 0.9 ≤ x + y < 1, 0 < x ≤ 0.9, 0 < y ≤ 0.9, M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, and may be selected from one or more of titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium; the coating layer includes carbon.

[0059] Therefore, the molar ratios of manganese, iron, doping elements, and phosphorus elements in the precursor material of this application are the same as those in the cathode material. Thus, when preparing the cathode material, it is only necessary to react the precursor material with a lithium source and an optional carbon source, reducing the types of raw materials, improving the compositional uniformity and batch consistency of the cathode material, and enhancing the specific capacity and cycling performance of the battery.

[0060] In any embodiment, the molar ratio of the compound Mn x Fe y M (1-x-y) HPO 4 ·nH 2 O in the precursor material to the lithium element in the lithium source is 1:(1.0 - 1.1); and / or,

[0061] The mass ratio of the precursor material to the carbon source is 1:(0.01 - 0.2); and / or,

[0062] The Dv50 particle size of the insoluble matter in the mixture obtained after grinding is 0.1 - 7.0 μm, optionally 0.1 - 5.0 μm; and / or,

[0063] The drying is carried out by a spray dryer, and the inlet air temperature of the spray dryer is 180°C - 350°C and the outlet air temperature is 90°C - 130°C; and / or,

[0064] The sintering temperature is 450°C - 800°C; and / or,

[0065] The sintering time is 6 - 20 h; and / or,

[0066] Sintering is carried out in an inert atmosphere.

[0067] The insoluble matter in the mixture obtained after grinding reaches a certain Dv50 particle size, which is beneficial to increasing the surface energy of the particles, improving the solid-solid reaction activity, shortening the diffusion path of lithium into the crystal interior of the precursor material, making the reaction to form the cathode material proceed more completely, and thus improving the electrical performance of the battery.

[0068] The adopted sintering temperature and sintering time are beneficial to making the reaction proceed more completely, thereby improving the electrical performance of the battery.

[0069] The seventh aspect of this application provides a positive electrode sheet, including the cathode material of the third or fourth aspect of this application, or the cathode material prepared by the method of the fifth or sixth aspect of this application.

[0070] The eighth aspect of this application provides a battery, including the positive electrode sheet of the seventh aspect of this application.

[0071] The ninth aspect of this application provides an electrical device, including the battery of the eighth aspect of this application. Description of the Drawings

[0072] Figure 1 is a schematic diagram of a battery cell according to an embodiment of the present application.

[0073] Figure 2 is Figure 1 an exploded view of the battery cell according to an embodiment of the present application shown in the figure.

[0074] Figure 3 is a schematic diagram of a battery module according to an embodiment of the present application.

[0075] Figure 4 is a schematic diagram of a battery pack according to an embodiment of the present application.

[0076] Figure 5 is Figure 4 an exploded view of the battery pack according to an embodiment of the present application shown in the figure.

[0077] Figure 6 is a schematic diagram of an electrical device using the battery cell as a power source according to an embodiment of the present application.

[0078] Figure 7 is a flowchart of the method for preparing the precursor material in Example 1 of the present application.

[0079] Figure 8 is an SEM photograph of the precursor material prepared in Example 1 of the present application.

[0080] Figure 9 is an SEM photograph of the precursor material prepared in Comparative Example 3 of the present application.

[0081] Figure 10 is an EDS image of the elemental analysis of lithium, manganese, iron, phosphorus, and cobalt of the positive electrode material prepared in Example 1 of the present application.

[0082] Description of the Reference Numerals:

[0083] 1 Battery pack; 2 Upper box body; 3 Lower box body; 4 Battery module; 5 Battery cell; 51 Housing; 52 Electrode assembly; 53 Top cover assembly. Detailed Embodiments

[0084] Hereinafter, embodiments of the precursor material, the method for preparing the precursor material, the cathode material, the method for preparing the cathode material, the cathode electrode sheet, the anode electrode sheet, the battery cell, the battery module, the battery pack, and the electrical device of the present application will be specifically described in detail with reference to the accompanying drawings as appropriate. However, there may be cases where unnecessary details are omitted. For example, there may be cases where details of well-known matters are omitted and repeated descriptions of actually identical structures are omitted. This is to prevent the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the accompanying drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter recited in the claims.

[0085] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a particular range. The range defined in this way can include or exclude the end values and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 - 120 and 80 - 110 are listed for a specific parameter, ranges of 60 - 110 and 80 - 120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all contemplated: 1 - 3, 1 - 4, 1 - 5, 2 - 3, 2 - 4, and 2 - 5. In the present application, unless otherwise stated, the numerical range "a - b" represents an abbreviated representation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0 - 5" represents that all real numbers between "0 - 5" have been fully listed herein, and "0 - 5" is only an abbreviated representation of these numerical combinations. Additionally, when it is stated that a certain parameter is an integer ≥2, it is equivalent to disclosing that the parameter is, for example, the integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0086] If there is no special instruction, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0087] If there is no special instruction, all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0088] Unless otherwise specified, all steps of this application can be carried out sequentially or randomly, preferably sequentially. For example, a method includes steps (a) and (b), which means the method may include steps (a) and (b) carried out sequentially, or may also include steps (b) and (a) carried out sequentially. For example, when it is mentioned that the method may further include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may also include steps (c), (a) and (b), etc.

[0089] Unless otherwise specified, the Dv50 particle size in this application refers to the particle size when the cumulative volume distribution value is 50%.

[0090] [Battery cell]

[0091] A battery cell, also known as a rechargeable battery or a storage battery, refers to a battery that can activate the active material through charging and continue to be used after the battery discharges.

[0092] Generally, a battery cell includes a positive electrode plate, a negative electrode plate, a separator and an electrolyte. During the charging and discharging process of the battery, active ions (such as lithium ions) are embedded and removed back and forth between the positive electrode plate and the negative electrode plate. The separator is arranged between the positive electrode plate and the negative electrode plate, mainly playing the role of preventing short circuit between the positive and negative electrodes, and at the same time allowing active ions to pass through. The electrolyte is between the positive electrode plate and the negative electrode plate, mainly playing the role of conducting active ions.

[0093] [Precursor material]

[0094] An embodiment of this application provides a precursor material, including the compound Mn x Fe y M (1-x-y) HPO 4 ·nH 2 O; wherein, 0.9 ≤ x + y < 1 (for example, x + y can be 0.9, 0.95, 0.99, 0.998, 0.999, 0.999 or the range composed of any of the foregoing numerical values), 0 < x ≤ 0.9 (for example, x can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or the range composed of any of the foregoing numerical values), 0 < y ≤ 0.9 (for example, y can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or the range composed of any of the foregoing numerical values), 0 ≤ n ≤ 6 (for example, n can be 0, 1, 2, 3, 4, 5 or 6); the M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements.

[0095] The conventional preparation method of the lithium iron manganese phosphate cathode material doped with elements is to prepare it through processes such as mechanically mixing a variety of raw materials including a manganese source, an iron source, a lithium source, a phosphorus source, a source of the doping element, etc., sand grinding to refine the particles, spray drying, and sintering; however, this method is prone to problems such as uneven composition, poor batch consistency, and poor electrical performance.

[0096] Although the mechanism is not yet clear, the applicant unexpectedly found that: the distribution of manganese, iron, phosphorus, and doping elements in the precursor material of the present application is uniform, and the batch consistency is good. The elements in the cathode material prepared using the precursor material of the present application are evenly distributed, and the batch consistency is good, thereby improving the electrical performance such as the specific capacity and cycle performance of the prepared battery.

[0097] In some embodiments, 0.992 ≤ x + y < 0.995; and / or, 0.513 ≤ x ≤ 0.658; and / or, 0.336 ≤ y ≤ 0.479; and / or, 0 ≤ n ≤ 1.

[0098] In some embodiments, the M includes one or more elements among titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, europium.

[0099] In some embodiments, the Dv50 particle size of the precursor material is 3 - 100 μm, optionally 5 - 50 μm, more optionally 8 - 20 μm, such as 3 μm, 4 μm, 5 μm, 8 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm or the range composed of any of the foregoing values.

[0100] The Dv50 particle size of the precursor material of the present application is within the above range. On the one hand, it is beneficial to the washing and filtration operations during the preparation of the precursor, improving the yield of the precursor material. On the other hand, when preparing the cathode material, it is beneficial to the suspension of the precursor particles and not easy to settle, thereby improving the efficiency of the mixing and grinding processes.

[0101] In the present application, the Dv50 particle size can be measured by conventional methods in the art. For example, a sample is added to deionized water to completely disperse the sample, and the Dv50 particle size is measured using a laser particle size analyzer (MasterSizer 2000).

[0102] In some embodiments, the tap density of the precursor material at 30 MPa is 1.35 - 2.5 g / cm 3 , optionally 1.5 - 2.5 g / cm 3 , such as 1.35 g / cm 3 、1.5 g / cm 3 、1.7 g / cm 3, 1.9 g / cm 3 , 2.0 g / cm 3 , 2.1 g / cm 3 , 2.2 g / cm 3 , 2.3 g / cm 3 , 2.4 g / cm 3 , 2.5 g / cm 3 or a range composed of any of the foregoing numerical values.

[0103] The tap density of the precursor material of the present application is within the above range, which is beneficial to improving the tap density of the cathode material, thereby enhancing the specific capacity of the battery.

[0104] In the present application, the tap density can be measured by conventional methods in the art. For example, the sample is placed in the mold of a tap density tester, and the tester automatically applies a pressure of 30 MPa to the powder until it is compacted. According to the cross-sectional area of the mold and the thickness of the powder at this time, the volume of the powder can be calculated. According to tap density = mass / volume, the tap density of the powder material can be measured.

[0105] In some embodiments, the compound Mn x Fe y M (1-x-y) HPO 4 ·nH 2 O in the precursor material has a mass content of 98% - 100%, such as 98.5%, 99%, 99.5%, 100% or a range composed of any of the foregoing numerical values.

[0106] The precursor material of the present application has a high content of the compound and a low content of impurities, so that the cathode material prepared has a low content of impurities, and the specific capacity and cycle performance of the battery are improved.

[0107] In some embodiments, the precursor material includes primary crystalline particles having a polyhedral morphology.

[0108] The precursor material of the present application includes primary crystalline particles having a polyhedral morphology, with flat and regular crystal planes and smaller particle gaps, which is beneficial to improving the tap density of the precursor material.

[0109] [Method for preparing precursor material]

[0110] One embodiment of the present application provides a method for preparing a precursor material, including the following steps:

[0111] Dissolve a soluble manganese source, a soluble iron source, and a source of soluble M element in a solvent to obtain a solution;

[0112] Slowly add the solution to a phosphoric acid solution for reaction, and obtain a reaction product after optional aging;

[0113] Filter the reaction product and dry the obtained filter residue to obtain a precursor material;

[0114] The precursor material includes the compound Mn x Fe y M (1-x-y) HPO 4 ·nH 2 O; wherein, 0.9 ≤ x + y < 1 (for example, x + y can be 0.9, 0.95, 0.99, 0.998, 0.999, 0.999 or the range composed of any of the foregoing values), 0 < x ≤ 0.9 (for example, x can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or the range composed of any of the foregoing values), 0 < y ≤ 0.9 (for example, y can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or the range composed of any of the foregoing values), 0 ≤ n ≤ 6 (for example, n can be 0, 1, 2, 3, 4, 5 or 6); the M element includes one or more of transition metal elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements other than manganese and iron elements, and can be optionally selected to include one or more elements of titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium.

[0115] Phosphoric acid can dissociate into various ions. The coprecipitation reaction between metal ions and the ions dissociated from phosphoric acid is relatively complex, with many side reactions, and it is easy to generate by-products in the form of gel-like, flocculent, amorphous and other particles. The coprecipitates prepared are generally a mixture of multiple precipitates, and it is not easy to obtain a precursor material with uniform composition, good batch consistency and low impurity content.

[0116] Therefore, in this application, a stable and homogeneous solution is first prepared from a soluble manganese source, a soluble iron source and a source of soluble M element, and then the solution is slowly added to a phosphoric acid solution to control and reduce side reactions. Then, through optional aging and drying of the filtered filter residue, a precursor material with uniform composition, good batch consistency and low impurity content is obtained. The elements in the cathode material prepared using this precursor material are evenly distributed and have good batch consistency, thereby improving the specific capacity and cycle performance of the battery.

[0117] In some embodiments, the precursor material is the precursor material described above.

[0118] In some embodiments, the soluble manganese source includes one or more of a soluble organic manganese source and a soluble inorganic manganese source, and can be optionally a soluble organic manganese source, more optionally one or more of soluble organic acid salts of manganese, and further optionally one or more of manganese acetate, manganese formate, manganese citrate, and manganese 2-hydroxypropionate.

[0119] In some embodiments, the soluble iron source includes one or more of a soluble organic iron source and a soluble inorganic iron source, optionally a soluble organic iron source, more optionally one or more of soluble organic acid salts containing iron, and further optionally one or more of ferrous acetate, ferrous formate, ferrous citrate, and ferrous 2-hydroxypropionate.

[0120] Among them, the use of a soluble organic manganese source and / or a soluble organic iron source is beneficial to reducing the impurity content in the precursor material, improving batch consistency, and thus improving the specific capacity and cycling performance of the battery.

[0121] In some embodiments, the source of the soluble M element includes one or more of an inorganic source of the soluble M element and an organic source of the soluble M element, optionally one or more of a soluble organic acid salt and a soluble inorganic acid salt containing the M element, and more optionally one or more of a sulfate, nitrate, chloride, formate, acetate, citrate, and 2-hydroxypropionate of the M element.

[0122] In some embodiments, at 25°C - 95°C, optionally 30°C - 90°C (such as 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, or a range composed of any of the foregoing values), the solution is slowly added to the phosphoric acid solution for reaction.

[0123] By controlling the ambient temperature at which the mixed metal solution is added to the phosphoric acid solution in the present application, side reactions can be reduced to obtain a precursor material with uniform composition, good batch consistency, and low impurity content, thereby improving the specific capacity and cycling performance of the battery.

[0124] In some embodiments, the feeding time of the solution is 10 - 300 min, optionally 15 - 300 min, more optionally 60 - 180 min, and further optionally 90 - 120 min, such as 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 150, 160, 180, 190, 200, 220, 240, 260, 280, 300 min, or a range composed of any of the foregoing values.

[0125] In some embodiments, the molar ratio of phosphoric acid in the phosphoric acid solution to the total amount of metal elements in the solution is 0.4 - 1.5, optionally 0.5 - 1.5, more optionally 0.8 - 1.2, and further optionally 0.9 - 1.1, such as 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, or a range composed of any of the foregoing values.

[0126] By controlling the molar ratio of phosphoric acid to the total metal elements in this application, the specific capacity of the battery can be improved.

[0127] In some embodiments, the total concentration of metal elements in the solution is 0.1 - 3.0 mol / L, optionally 0.5 - 2.5 mol / L, more optionally 1.0 - 2.0 mol / L, such as 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2.0 mol / L, 2.1 mol / L, 2.2 mol / L, 2.3 mol / L, 2.4 mol / L, 2.5 mol / L, 2.6 mol / L, 2.8 mol / L, 2.9 mol / L, 3.0 mol / L or the range composed of any of the foregoing values.

[0128] In some embodiments, the concentration of phosphoric acid in the phosphoric acid solution is 0.1 - 3.0 mol / L, optionally 0.5 - 2.5 mol / L, more optionally 1.0 - 2.0 mol / L, such as 0.1 mol / L, 0.2 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L, 1.3 mol / L, 1.5 mol / L, 1.7 mol / L, 1.9 mol / L, 2.0 mol / L, 2.1 mol / L, 2.3 mol / L, 2.5 mol / L, 2.7 mol / L, 2.8 mol / L, 2.9 mol / L, 3.0 mol / L or the range composed of any of the foregoing values.

[0129] By controlling the rate of adding the solution to the phosphoric acid solution in this application, it is beneficial to control and reduce side reactions, and a precursor material with uniform composition, good batch consistency and low impurity content can be prepared, thereby improving the electrical performance of the battery.

[0130] In some embodiments, the molar amount of element M in the solution accounts for 0.1% - 10% of the total molar amount of metal elements, such as 0.3%, 0.5%, 1%, 3%, 5%, 7%, 9%, 10% or the range composed of any of the foregoing values.

[0131] In some embodiments, the molar amount of Mn element in the solution accounts for 30% - 85% of the total molar amount of metal elements, such as 35%, 40%, 45%, 50%, 55%, 58%, 60%, 65%, 70%, 75%, 80%, 85% or the range composed of any of the foregoing values.

[0132] In this application, the molar ratio of each metal element in the precursor product can be adjusted by controlling the concentration of each metal element in the solution.

[0133] In some embodiments, the aging temperature is 40°C - 98°C, optionally 60°C - 95°C, such as 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 98°C or the range composed of any of the foregoing values.

[0134] In some embodiments, the aging time is 10 - 500 min, optionally 30 - 300 min, such as 10, 20, 30, 40, 50, 70, 100, 120, 150, 170, 190, 200, 240, 270, 300, 330, 350, 380, 400, 420, 440, 460, 480, 500 min or the range composed of any of the foregoing values.

[0135] In some embodiments, the reaction and / or aging is carried out under the condition that the pH value is 1.5 - 4.5, such as the pH value is 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or the range composed of any of the foregoing values.

[0136] In some embodiments, the reaction and / or aging is carried out under stirring conditions.

[0137] Aging is beneficial to the crystallization and growth of the precipitate, so as to reduce the proportion of amorphous particles in the precursor material, thereby obtaining a precursor material with better crystallinity and higher tap density, thereby improving the specific capacity and cycling performance of the battery.

[0138] In some embodiments, the dissolution is carried out at 25°C - 80°C (such as 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C or the range composed of any of the foregoing values); and / or,

[0139] The solvent is water.

[0140] In some embodiments, the filtration is vacuum suction filtration, positive pressure filtration or centrifugal filtration.

[0141] In some embodiments, before drying, the filter residue is washed, and optionally the filter residue is washed with water.

[0142] In some embodiments, the drying temperature is 80°C - 500°C, optionally 120°C - 400°C, and more optionally 150°C - 300°C.

[0143] In some embodiments, the drying time is 10 - 300 min.

[0144] [Positive electrode material]

[0145] One embodiment of the present application provides a positive electrode material, including the compound LiMn x Fe y M (1-x-y) PO 4 , where 0.9 ≤ x + y < 1 (for example, x + y can be 0.9, 0.95, 0.99, 0.998, 0.999, 0.999 or the range composed of any of the foregoing values), 0 < x ≤ 0.9 (for example, x can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or the range composed of any of the foregoing values), 0 < y ≤ 0.9 (for example, x can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or the range composed of any of the foregoing values), and M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, and is optionally selected from one or more elements including titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium;

[0146] Moreover, the preparation raw materials of the positive electrode material include the foregoing precursor material of the present application or the precursor material prepared by the foregoing method of the present application.

[0147] Another embodiment of the present application provides a positive electrode material, including a core and a coating layer; the core includes the compound LiMn x Fe y M (1-x-y) PO 4; wherein, 0.9 ≤ x + y < 1 (for example, x + y can be 0.9, 0.95, 0.99, 0.998, 0.999, 0.9995 or a range composed of any of the foregoing values), 0 < x ≤ 0.9 (for example, x can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or a range composed of any of the foregoing values), 0 < y ≤ 0.9 (for example, x can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or a range composed of any of the foregoing values), the M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, and can be selected to include one or more of titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium; the coating layer includes carbon;

[0148] Moreover, the preparation raw materials of the positive electrode material include the foregoing precursor material of the present application or the precursor material prepared by the foregoing method of the present application.

[0149] Thus, the molar ratios of manganese element, iron element, doping element, and phosphorus element in the precursor material of the present application are the same as those in the positive electrode material, so that the types of raw materials are reduced during the preparation of the positive electrode material, thereby improving the compositional uniformity and batch consistency of the positive electrode material, and improving the specific capacity and cycle performance of the battery.

[0150] [Method for preparing positive electrode material]

[0151] One embodiment of the present application provides a method for preparing a positive electrode material, including the following steps:

[0152] Mix the foregoing precursor material of the present application or the precursor material prepared by the foregoing method of the present application and a lithium source in a solvent, grind, dry, and sinter to obtain the positive electrode material;

[0153] wherein, the positive electrode material includes the compound LiMn x Fe y M (1-x-y) PO 4 , wherein, 0.9 ≤ x + y < 1, 0 < x ≤ 0.9, 0 < y ≤ 0.9, the M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, and can be selected to include one or more of titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium.

[0154] Another embodiment of the present application provides a method for preparing a positive electrode material, including the following steps:

[0155] Mix the precursor material described above in this application or the precursor material prepared by the method described above in this application, a lithium source, and a carbon source in a solvent, grind, dry, and sinter to obtain a cathode material;

[0156] Among them, the cathode material includes a core and a coating layer; the core includes the compound LiMn x Fe y M (1-x-y) PO 4 ; where 0.9 ≤ x + y < 1, 0 < x ≤ 0.9, 0 < y ≤ 0.9, and M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, and may be selected from one or more elements including titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, europium, etc.; the coating layer includes carbon.

[0157] Thus, the molar ratios of manganese element, iron element, doping element, and phosphorus element in the precursor material of this application are the same as those in the cathode material. Therefore, when preparing the cathode material, only the precursor material needs to react with the lithium source and an optional carbon source, reducing the types of raw materials, improving the compositional uniformity and batch consistency of the cathode material, and improving the specific capacity and cycling performance of the battery.

[0158] In some embodiments, the molar ratio of the compound Mn x Fe y M (1 -x- y) HPO 4 ·nH 2 O in the precursor material to the lithium element in the lithium source is 1:(1.0 - 1.1).

[0159] In some embodiments, the mass ratio of the precursor material to the carbon source is 1:(0.01 - 0.2), such as 1:0.01, 1:0.02, 1:0.03, 1:0.05, 1:0.07, 1:0.09, 1:0.1, 1:0.12, 1:0.15, 1:0.16, 1:0.17, 1:0.18, 1:0.19, 1:0.2, or a range composed of any of the foregoing values.

[0160] In some embodiments, the Dv50 particle size of the insoluble matter in the mixture obtained after grinding is 0.1 - 7.0 μm, optionally 0.1 - 5.0 μm, such as 0.1 μm, 0.3 μm, 0.5 μm, 0.7 μm, 0.9 μm, 1.0 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2.0 μm, 2.2 μm, 2.5 μm, 2.7 μm, 2.8 μm, 3.0 μm, 3.3 μm, 3.6 μm, 3.8 μm, 4.0 μm, 4.2 μm, 4.5 μm, 4.7 μm, 5.0 μm, 5.3 μm, 5.5 μm, 5.7 μm, 6.0 μm, 6.3 μm, 6.5 μm, 6.7 μm, 7 μm or the range composed of any of the foregoing values.

[0161] The insoluble matter in the mixture obtained after grinding reaches a certain Dv50 particle size, which is beneficial to increasing the surface energy of the particles, improving the solid-solid reaction activity, shortening the diffusion path of lithium into the crystal interior of the precursor material, making the reaction for generating the cathode material more complete, and thus improving the electrical performance of the battery.

[0162] In some embodiments, the drying is carried out by a spray dryer, and the inlet air temperature of the spray dryer is 180°C - 350°C and the outlet air temperature is 90°C - 130°C.

[0163] In some embodiments, the sintering temperature is 450°C - 800°C, such as 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C or the range composed of any of the foregoing values.

[0164] In some embodiments, the sintering time is 6 - 20 h, such as 6 h, 8 h, 9 h, 10 h, 12 h, 14 h, 15 h, 17 h, 18 h, 19 h, 20 h or the range composed of any of the foregoing values.

[0165] In some embodiments, the sintering is carried out in an inert atmosphere.

[0166] The adopted sintering temperature and sintering time are beneficial to making the reaction more complete, thereby improving the electrical performance of the battery.

[0167] [Cathode electrode sheet]

[0168] The cathode electrode sheet generally includes a cathode current collector and a cathode film layer provided on at least one surface of the cathode current collector, and the cathode film layer includes the foregoing cathode material or the cathode material prepared by the foregoing method.

[0169] During the charge and discharge process of the battery, the insertion and extraction and consumption of Li will occur, and the molar content of Li is different when the battery is discharged to different states. In the listing of the positive electrode materials in this application, the molar content of Li is the initial state of the material, that is, the state before feeding. When the positive electrode material is applied to the battery system, after charge and discharge cycling, the molar content of Li will change.

[0170] In the listing of the positive electrode materials in this application, the molar content of O is only the theoretical state value, and the release of oxygen from the lattice will cause the molar content of oxygen to change, and the actual molar content of O will show fluctuations.

[0171] As an example, the positive electrode current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0172] In some embodiments, the positive electrode current collector can be a metal foil or a composite current collector. For example, as the metal foil, aluminum foil can be used. The composite current collector can include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0173] In some embodiments, as an example, the positive electrode material may further include the following materials: lithium transition metal oxides and their modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as the positive electrode active material of the battery can also be used. Among them, examples of lithium transition metal oxides may include but are not limited to lithium cobalt oxide (such as LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 , LiMn 2 O 4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 (which can also be abbreviated as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (which can also be abbreviated as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25O 2 (which can also be abbreviated as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O 2 (which can also be abbreviated as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O 2 (which can also be abbreviated as NCM 811 )、lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O 2 ) and at least one of its modified compounds, etc.

[0174] In some embodiments, the positive electrode film layer may further optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride - tetrafluoroethylene - propylene terpolymer, vinylidene fluoride - hexafluoropropylene - tetrafluoroethylene terpolymer, tetrafluoroethylene - hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0175] In some embodiments, the positive electrode film layer may further optionally include a conductive agent. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0176] In some embodiments, the positive electrode plate can be prepared in the following manner: dispersing the components for preparing the positive electrode plate, such as the positive electrode active material, conductive agent, binder, and any other components, in a solvent (such as N - methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry on the positive electrode current collector, and after processes such as drying and cold pressing, the positive electrode plate can be obtained.

[0177] [Negative electrode plate]

[0178] The negative electrode plate includes a negative electrode current collector and a negative electrode film layer provided on at least one surface of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.

[0179] As an example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode film layer is provided on any one or both of the two opposite surfaces of the negative electrode current collector.

[0180] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, copper foil may be used. The composite current collector may include a polymer material substrate layer and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0181] In some embodiments, the negative electrode active material may be a negative electrode active material for batteries well-known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based materials may be selected from at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based materials may be selected from at least one of elemental tin, tin oxides, and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as the negative electrode active material of the battery may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0182] In some embodiments, the negative electrode film layer may also optionally include a binder. As an example, the binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0183] In some embodiments, the negative electrode film layer may also optionally include a conductive agent. As an example, the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0184] In some embodiments, the negative electrode film layer may also optionally include other additives, such as thickeners (such as sodium carboxymethyl cellulose (CMC-Na)), etc.

[0185] In some embodiments, the negative electrode plate may be prepared by the following method: dispersing the components for preparing the negative electrode plate, such as the negative electrode active material, the conductive agent, the binder, and any other components, in a solvent (such as deionized water) to form a negative electrode slurry; coating the negative electrode slurry on the negative electrode current collector, and after processes such as drying and cold pressing, the negative electrode plate can be obtained.

[0186] [Electrolyte]

[0187] The electrolyte functions to conduct ions between the positive electrode plate and the negative electrode plate. There is no specific limitation on the type of the electrolyte in this application, and it can be selected according to requirements. For example, the electrolyte can be liquid, gel-like, or all-solid-state.

[0188] In some embodiments, the electrolyte is liquid and includes an electrolyte salt and a solvent.

[0189] In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium difluoro bis(oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate.

[0190] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0191] In some embodiments, the electrolyte solution may optionally further include additives. By way of example, the additives can include negative electrode film-forming additives, positive electrode film-forming additives, and can also include additives that can improve certain battery performances, such as additives for improving the overcharge performance of the battery, additives for improving the high-temperature or low-temperature performance of the battery, etc.

[0192] [Separator membrane]

[0193] In some embodiments, the battery cell further includes a separator membrane. There is no particular limitation on the type of the separator membrane in this application, and any well-known porous structure separator membrane with good chemical stability and mechanical stability can be selected.

[0194] In some embodiments, the material of the separator membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator membrane can be a single-layer thin film or a multi-layer composite thin film, without particular limitation. When the separator membrane is a multi-layer composite thin film, the materials of each layer can be the same or different, without particular limitation.

[0195] In some embodiments, the positive electrode plate, the negative electrode plate, and the separator membrane can be made into an electrode assembly through a winding process or a stacking process.

[0196] In some embodiments, the battery cell may include an outer package. The outer package can be used to encapsulate the above-mentioned electrode assembly and electrolyte.

[0197] In some embodiments, the outer packaging of the battery cell can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the battery cell can also be a soft pack, such as a pouch-type soft pack. The material of the soft pack can be plastic, and examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate, etc.

[0198] The present application places no particular limitation on the shape of the battery cell, and it can be cylindrical, square, or any other arbitrary shape. For example, Figure 1 is a battery cell 5 with a square structure as an example.

[0199] In some embodiments, referring to Figure 2 , the outer packaging can include a housing 51 and a cover plate 53. Among them, the housing 51 can include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose to form a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The positive electrode plate, the negative electrode plate, and the separator can be formed into an electrode assembly 52 through a winding process or a stacking process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 52. The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, and those skilled in the art can select according to specific actual needs.

[0200] In some embodiments, the battery cells can be assembled into a battery module. The number of battery cells contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

[0201] Figure 3 is a battery module 4 as an example. Referring to Figure 3 , in the battery module 4, multiple battery cells 5 can be arranged in sequence along the length direction of the battery module 4. Of course, they can also be arranged in any other arbitrary manner. Further, the multiple battery cells 5 can be fixed by fasteners.

[0202] Optionally, the battery module 4 can further include a housing with a receiving space, and multiple battery cells 5 are accommodated in the receiving space.

[0203] In some embodiments, the above battery module can be further assembled into a battery pack. The number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0204] Figure 4 and Figure 5 is a battery pack 1 as an example. Referring to Figure 4 and Figure 5, a battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box. The battery box includes an upper box body 2 and a lower box body 3. The upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery modules 4. The plurality of battery modules 4 can be arranged in the battery box in any manner.

[0205] In addition, the present application also provides an electrical device, which includes at least one of the battery cells, battery modules, or battery packs provided by the present application. The battery cells, battery modules, or battery packs can be used as the power supply of the electrical device or as the energy storage unit of the electrical device. The electrical device can include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships, satellites, energy storage systems, etc., but is not limited thereto.

[0206] As the electrical device, the battery cells, battery modules, or battery packs can be selected according to its usage requirements.

[0207] Figure 6 is an electrical device as an example. The electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the high power and high energy density requirements of the electrical device for the battery cells, a battery pack or a battery module can be used.

[0208] [Embodiment]

[0209] Hereinafter, embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application. For those not specified in the embodiments regarding specific technologies or conditions, they shall be carried out according to the technologies or conditions described in the literature in the field or according to the product specifications. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0210] Embodiment 1

[0211] (1) Preparation of the precursor material (as Figure 7 shown):

[0212] According to the molar ratio of Mn:Fe:Co of 0.597:0.398:0.005, 2.866 mol of manganese acetate, 1.910 mol of ferrous acetate, and 0.024 mol of cobalt sulfate are added to a stirring tank, and pure water is added according to the total metal ion molar concentration of 1.60 mol / L and stirred to dissolve. The stirring function is turned on and the water bath heating function is turned on. The feed liquid is heated to 40 °C and kept warm. After all the powders are dissolved, 3.0 L of the metal salt solution is obtained for standby.

[0213] According to the above-mentioned total molar ratio of metal ions to phosphorus of 1:1.100, 5.280 mol of concentrated phosphoric acid with a solute mass concentration of 85% is placed in a stirring tank, and pure water is added according to the molar concentration of the phosphoric acid solution of 1.32 mol / L and stirred evenly. Then the water bath heating function is turned on, and the feed liquid is heated to 60 °C and kept warm to obtain 4.0 L of phosphoric acid solution for standby.

[0214] Keep the water bath temperature of the phosphoric acid solution at 60 °C. Under stirring conditions, the above-mentioned metal salt solution is evenly added to the phosphoric acid solution by a metering pump for mixing reaction. Set the volume flow rate of the metal salt solution to about 0.03 L / min, and control the time for all the feed liquid to be added within 100 min. After the feeding is completed, the feed liquid is heated to 85 °C under stirring conditions and aged for another 120 min to make the reaction complete and obtain the slurry. At this time, an online pH meter is used to measure the pH value of the system during the above feeding, reaction, and aging processes to be 2 - 3.

[0215] Transfer the slurry to a vacuum filtration device with a maximum vacuum pressure of -0.06 MPa, filter and collect the solid precipitate; and add about 3.6 L of pure water for online washing to obtain the precursor filter cake; transfer the precursor filter cake to a blast drying oven, set the drying temperature at 150 °C, and dry for 120 min. At this time, the material is basically of constant weight, and the precursor material is obtained.

[0216] (2) Preparation of the positive electrode material:

[0217] According to the molar ratio of the compound in the precursor material to the lithium element in the lithium source of 1:1, 510.28 g of the precursor material (the mass fraction of the compound in the precursor material is 99.0%, and the amount of substance is 3.000 mol) and 110.84 g of lithium carbonate (the amount of substance of the lithium element in lithium carbonate is 3.000 mol) are weighed; and according to the mass ratio of the precursor material to the carbon source of 1:0.12, 61.23 g of glucose is weighed. The above-mentioned materials are added together to 1443.36 g of pure water and mixed evenly, then put into a ball mill and ground to a particle size Dv50 of 0.8 μm to obtain the slurry; the slurry is dried by spray drying, with an inlet air temperature of 220 °C and an outlet air temperature of 105 °C to obtain the powder; using an atmosphere box furnace, under a nitrogen atmosphere, the powder is sintered at 700 °C for 12 h to obtain the positive electrode material.

[0218] (3) Preparation of the positive electrode plate:

[0219] Weigh 0.3000 g of polyvinylidene fluoride binder (PVDF) with an analytical balance (accuracy 0.0001 g) into 10.8 g of N-methylpyrrolidone (NMP), stir and dissolve completely; then add 2.4000 g of the above-mentioned cathode material and 0.3000 g of carbon black conductive agent (SP), stir evenly to obtain a paste. Use a coater to evenly coat the paste on the aluminum foil, and dry it in a vacuum drying oven. After removing the solvent NMP, roll press and punch it to obtain a circular sheet with a diameter of 16.0 mm as the positive electrode plate.

[0220] (4) Negative electrode plate: Use a lithium metal sheet.

[0221] (5) Separator: Use a PE-PP composite membrane.

[0222] (6) Preparation of electrolyte:

[0223] Mix ethylene carbonate (EC) and dimethyl carbonate (DMC) in a volume ratio of 1:1, and then dissolve LiPF 6 uniformly in the above solution to obtain an electrolyte. In this electrolyte, the concentration of LiPF 6 is 1 mol / L.

[0224] (7) Preparation of coin cell:

[0225] Assemble the above positive electrode plate, separator, negative electrode plate, and electrolyte into a CR2032 coin cell.

[0226] The battery preparation methods of Examples 2-33 and Comparative Examples 1-2 are similar to that of Example 1. For the different preparation methods and product parameters, please refer to Tables 1-3.

[0227] Example 32

[0228] (1) Preparation of precursor material:

[0229] According to the molar ratio of Mn:Fe:Co of 0.597:0.398:0.005, add 2.866 mol of manganese acetate, 1.910 mol of iron acetate, and 0.024 mol of cobalt sulfate to a stirring tank, and add pure water according to the total metal ion molar concentration of 1.60 mol / L, stir and dissolve, and turn on the water bath heating function. Heat the feed liquid to 40 °C and keep it warm. After all the powder materials are dissolved, obtain 3.0 L of metal salt solution for standby.

[0230] According to the molar ratio of the above total metal ions to phosphorus of 1:1.100, add 5.280 mol of concentrated phosphoric acid with a solute mass concentration of 85% to the stirring tank, and add pure water and stir evenly according to the molar concentration of the phosphoric acid solution of 1.32 mol / L. Turn on the water bath heating function, heat the feed liquid to 60 °C and keep it warm to obtain 4.0 L of phosphoric acid solution for standby.

[0231] Keep the water bath temperature of the phosphoric acid solution at 60 °C. Under stirring conditions, add the above metal salt solution to the phosphoric acid solution at one time and mix for reaction. For the mixed slurry at this time, use an on-line pH meter to measure the pH value of the system during the above feeding and reaction processes to be 2 - 3.

[0232] Transfer the slurry to a vacuum filtration device with a maximum vacuum pressure of -0.06 MPa, filter and collect the solid precipitate; add about 3.6 L of pure water for on-line washing to obtain a precursor filter cake; transfer the precursor filter cake to a forced-air drying oven, set the drying temperature at 150 °C, and dry for 120 min. At this time, the material is basically of constant weight to obtain the precursor material.

[0233] Steps (2)-(7) are the same as steps (2)-(7) in Example 1.

[0234] Example 33

[0235] (1) Preparation of the precursor material:

[0236] According to the molar ratio of Mn:Fe:Co of 0.597:0.398:0.005, add 3.582 mol of manganese chloride, 2.388 mol of ferrous chloride, and 0.030 mol of cobaltous chloride to a stirring tank, and add pure water according to the total metal ion molar concentration of 1.6 mol / L, stir to dissolve, and turn on the water bath heating function to heat the liquid material to 40 °C for insulation. After all the powder materials are dissolved, obtain 6.0 L of metal salt solution for standby.

[0237] According to the molar ratio of the above total metal ions to phosphorus of 1:1.1, add 7.2 mol of disodium hydrogen phosphate to the stirring tank, and add pure water according to the molar concentration of the disodium hydrogen phosphate solution of 1.0 mol / L, stir to dissolve, and turn on the water bath heating function to heat the liquid material to 60 °C for insulation to prepare 7.2 L of phosphorus source solution for standby.

[0238] Keep the water bath temperature of the phosphorus source solution at 60 °C. Under stirring conditions, use a metering pump to uniformly add the above metal salt solution to the phosphorus source solution and mix for reaction. Set the volume flow rate of the metal salt solution to be about 0.06 L / min, and control the time for all the liquid materials to be added within 100 min. For the mixed slurry at this time, use an on-line pH meter to measure the pH value of the system during the above feeding and reaction processes to be 4 - 6.

[0239] Transfer the slurry to a vacuum filtration device with a maximum vacuum pressure of -0.06 MPa, filter and collect the solid precipitate; add about 3.6 L of pure water for on-line washing to obtain a precursor filter cake; transfer the precursor filter cake to a forced-air drying oven, set the drying temperature at 300 °C, and dry for 120 min. At this time, the material is basically of constant weight to obtain the precursor material.

[0240] (2) Preparation of the positive electrode material:

[0241] Weigh 516.01 g of the precursor material (the mass fraction of the compound in the precursor material is 97.90%, and the amount of substance is 3.000 mol) and 110.84 g of lithium carbonate (the amount of substance of lithium element in lithium carbonate is 3.000 mol) according to the molar ratio of the compound in the precursor material to the lithium element in the lithium source being 1:1; and weigh 61.92 g of glucose according to the mass ratio of the precursor material to the carbon source being 1:0.12. Add the above materials to 1443.36 g of pure water and mix evenly. Then put them into a ball mill and grind until the Dv50 particle size is 0.8 μm to obtain a slurry; dry the slurry by spray drying, with the inlet air temperature of 220 °C and the outlet air temperature of 105 °C to obtain a powder; use an atmosphere box furnace, under a nitrogen atmosphere, sinter the powder at 700 °C for 12 h to obtain the positive electrode material.

[0242] Steps (3)-(7) are the same as steps (3)-(7) of Example 1.

[0243] Comparative Example 1

[0244] (1) Preparation of the positive electrode material

[0245] According to the molar ratio of Li:Mn:Fe:Co:PO 4 being 1.000:0.597:0.398:0.005:1.000, first add 2.400 mol of lithium carbonate and 4.800 mol of concentrated phosphoric acid with a solute mass concentration of 85% to 5945.63 g of pure water and mix and react to obtain a lithium dihydrogen phosphate solution. Then continue to add 2.866 mol of manganese oxalate, 1.910 mol of iron oxalate, 0.024 mol of cobalt oxalate, and 61.23 g of glucose, and mix evenly. Put them into a ball mill and grind until the Dv50 particle size is 0.8 μm to obtain a slurry; dry the slurry by spray drying, with the inlet air temperature of 220 °C and the outlet air temperature of 105 °C to obtain a powder; use an atmosphere box furnace, under a nitrogen atmosphere, sinter the powder at 700 °C for 12 h to obtain the positive electrode material.

[0246] Steps (2)-(6) are the same as steps (3)-(7) of Example 1.

[0247]

[0248]

[0249]

[0250]

[0251]

[0252] Material testing and battery testing

[0253] (1) Testing of mass fractions of various elements and chemical formulas of compounds in the precursor and cathode material:

[0254] Weigh 0.2 g of the precursor material or cathode material into a 100 mL beaker, add 10 mL of 10% w / w nitric acid solution, heat and digest at 120 °C for 0.5 hours, then make up the volume to 100 mL with a 100 mL volumetric flask; then pipette 1 mL and make up the volume to 100 mL with a volumetric flask to obtain the test solution.

[0255] Use an inductively coupled plasma optical emission spectrometer (ICP-OES, instrument brand: Agilent 5800) to measure the mass fractions of lithium, manganese, iron, phosphorus, and doping elements in the test solution. According to the mass fractions of various elements, calculate the molar ratios of various elements in the precursor material or cathode material, so as to determine the chemical formula of the compound.

[0256] According to the measured mass fraction of phosphorus element in the precursor material and in combination with the above chemical formula, calculate the compound mass content in the precursor material.

[0257] (2) Testing of Dv50 particle size:

[0258] Take an appropriate amount of the sample, add 20 mL of deionized water, and ultrasonically treat for 5 minutes (53 KHz, 120 W) to completely disperse the sample. Use a laser particle size analyzer (MasterSizer 2000) to measure the Dv50 particle size of the material.

[0259] (3) Evaluation of microscopic morphology and micro-area element distribution:

[0260] Use a scanning electron microscope (SEM, instrument brand: ZEISS sigma 300) to observe the microscopic morphology of the precursor materials of Example 1 and Comparative Example 3.

[0261] As Figure 8 shown, the precursor material of Example 1 is primary crystalline particles with a polyhedral morphology, the crystal planes are flat and regular, and there is little amorphous, honeycomb-like, and dendritic crystallization, indicating a high crystallinity of the precursor material.

[0262] As Figure 9 shown, the precursor material obtained in Comparative Example 3 has an uneven microscopic morphology, not only showing needle-like shapes but also having large particles, with uneven particle sizes. In addition, no obvious crystal planes can be observed, from which it is speculated that an amorphous precursor material is formed.

[0263] The element distribution in the micro-region of lithium, manganese, iron, phosphorus and the doping element cobalt in the cathode material obtained in Example 1 was characterized by an energy dispersive spectrometer (EDS).

[0264] As Figure 10 shown, the element distribution in the cathode material of Example 1 is relatively uniform.

[0265] (4) Compaction density test:

[0266] Weigh 0.6000 g of the precursor material and place it in the mold of the compaction density tester. The tester automatically applies a pressure of 30 MPa to the powder until it is compacted. According to the cross-sectional area of the mold and the thickness of the powder at this time, the volume of the powder can be calculated. According to the compaction density = mass / volume, the compaction density of the powder material can be measured.

[0267] (5) Test of the discharge specific capacity of the battery:

[0268] Using the Shenzhen Neware battery test system, the coin-type battery was cycled for charge and discharge at a charge and discharge rate of 0.1C. The number of cycles was 10 times, the test temperature was 25.0 °C, and the charge and discharge voltage was 2.0 V to 4.3 V. The discharge specific capacity at a charge and discharge rate of 0.1C was obtained by dividing the initial discharge capacity by the mass of the cathode material on the electrode.

[0269] (6) Test of the cycle capacity retention rate of the battery:

[0270] Using the Shenzhen Neware battery test system, the coin-type battery was cycled for charge and discharge at a charge and discharge rate of 1.0C. The number of cycles was 100 times, the test temperature was 25.0 °C, and the charge and discharge voltage was 2.0 V to 4.3 V. The percentage of the discharge capacity at the 50th cycle to the discharge capacity at the 1st cycle is the cycle capacity retention rate.

[0271] The test results are shown in Table 4.

[0272] Table 4: Performance test results of Examples 1-33 and Comparative Examples 1-2

[0273]

[0274]

[0275] According to the above results, it can be seen that:

[0276] Compared with Comparative Example 1 where no precursor material was prepared and the cathode material was prepared by a conventional method, the specific capacity of the batteries in Examples 1-26 of this application was significantly improved;

[0277] Compared with Comparative Example 2 where the precursor material of this application was not used, the specific capacity and the cycle capacity retention rate of the batteries in Examples 1-33 of this application were both significantly improved;

[0278] Compared with Example 32 where a one-time feeding method was used to prepare the precursor material without aging, the specific capacity of the batteries of Examples 1-26 of the present application was significantly increased;

[0279] Compared with Example 33 where inorganic raw materials were used to prepare the precursor material, both the specific capacity and the cycling capacity retention rate of the batteries of Examples 1-26 of the present application were significantly increased;

[0280] Compared with Example 22 where a lower compaction density of the precursor material was used, the batteries of Examples 1, 4-5 of the present application had a higher specific capacity;

[0281] Compared with Example 23 where a higher feeding and reaction temperature was used to prepare the precursor material, the batteries of Examples 1, 8-9 of the present application had a higher specific capacity and cycling capacity retention rate;

[0282] Compared with Example 24 where a lower molar ratio of phosphoric acid to total metal elements was used when preparing the precursor, the batteries of Examples 1, 10-13 of the present application had a higher specific capacity;

[0283] Compared with Example 25 where a lower aging temperature and a longer aging time were used to prepare the precursor material, the batteries of Examples 1, 14-15 of the present application had a higher specific capacity and cycling capacity retention rate; compared with Example 26 where a higher aging temperature and a shorter aging time were used to prepare the precursor material, the batteries of Examples 1, 14-15 of the present application had a higher specific capacity and cycling capacity retention rate;

[0284] Compared with Example 27 where a larger Dv50 particle size of the insoluble matter after grinding was used when preparing the positive electrode material, the batteries of Examples 1, 20-21 of the present application had a higher specific capacity and cycling capacity retention rate;

[0285] Compared with Example 28 where a smaller amount of carbon source was used when preparing the positive electrode material, the batteries of Examples 1, 19 of the present application had a higher specific capacity and cycling capacity retention rate.

[0286] It should be noted that the present application is not limited to the above embodiments. The above embodiments are only examples, and embodiments with the same structure and the same effect as the technical idea within the technical solution scope of the present application are included in the technical scope of the present application. In addition, within the scope of not departing from the gist of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other ways constructed by combining some of the constituent elements of the embodiments are also included in the scope of the present application.

Claims

1. A precursor material comprising a compound Mn x Fe y M (1-x-y) HPO 4 ·nH 2 O; Among them, 0.9 ≤ x + y < 1, 0 < x ≤ 0.9, 0 < y ≤ 0.9, 0 ≤ n ≤ 6; the M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements.

2. The precursor material according to claim 1, Among them, 0.992 ≤ x + y < 0.995; and / or, 0.513 ≤ x ≤ 0.658; and / or, 0.336 ≤ y ≤ 0.479; and / or, 0 ≤ n ≤ 1.

3. The precursor material according to claim 1 or 2, Among them, The M includes one or more elements of titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, europium.

4. The precursor material according to any one of claims 1 to 3, Among them, The Dv50 particle size of the precursor material is 3 - 100 μm, optionally 5 - 50 μm, more optionally 8 - 20 μm; and / or, The compacted density of the precursor material under 30 MPa is 1.35 - 2.5 g / cm 3 ; and / or, The compound Mn in the precursor material x Fe y M (1-x-y) HPO 4 ·nH 2 O has a mass content of 98% - 100%; and / or, The precursor material includes primary crystalline particles with a polyhedral morphology.

5. A method for preparing a precursor material, comprising the following steps: Dissolve a soluble manganese source, a soluble iron source, and a source of soluble M element in a solvent to obtain a solution; Slowly add the solution to a phosphoric acid solution for reaction, and obtain a reaction product after optional aging; Filter the reaction product, and dry the obtained filter residue to obtain a precursor material; The precursor material includes the compound Mn x Fe y M (1-x-y) HPO 4 ·nH 2 O; wherein, 0.9 ≤ x + y < 1, 0 < x ≤ 0.9, 0 < y ≤ 0.9, 0 ≤ n ≤ 6; the M element includes one or more of transition metal elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements other than manganese and iron elements, and may be selected from one or more elements including titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium.

6. The method according to claim 5, Among them, The soluble manganese source includes one or more of a soluble organic manganese source and a soluble inorganic manganese source, optionally a soluble organic manganese source, more optionally one or more of soluble organic acid salts containing manganese, and further optionally one or more of manganese acetate, manganese formate, manganese citrate, manganese 2 - hydroxypropionate; and / or, The soluble iron source includes one or more of a soluble organic iron source and a soluble inorganic iron source, optionally a soluble organic iron source, more optionally one or more of soluble organic acid salts containing iron, and further optionally one or more of ferrous acetate, ferrous formate, ferrous citrate, ferrous 2 - hydroxypropionate; and / or, The source of soluble M element includes one or more of an inorganic source of soluble M element and an organic source of soluble M element, optionally one or more of soluble organic acid salts and soluble inorganic acid salts containing M element, and more optionally one or more of sulfates, nitrates, chlorides, formates, acetates, citrates, 2 - hydroxypropionates of M element.

7. The method according to claim 5 or 6, Among them, React the solution by slowly adding it to the phosphoric acid solution at 25°C - 95°C; and / or, The feeding time of the solution is 10 - 300 min, optionally 15 - 300 min, more optionally 60 - 180 min; and / or, The molar ratio of phosphoric acid in the phosphoric acid solution to the total amount of metal elements in the solution is 0.4 - 1.5, optionally 0.5 - 1.5, more optionally 0.8 - 1.2; and / or, The total concentration of metal elements in the solution is 0.1 - 3.0 mol / L, optionally 0.5 - 2.5 mol / L, more optionally 1.0 - 2.0 mol / L; and / or, The concentration of phosphoric acid in the phosphoric acid solution is 0.1 - 3.0 mol / L, optionally 0.5 - 2.5 mol / L, more optionally 1.0 - 2.0 mol / L; and / or, The molar amount of element M in the solution accounts for 0.1% - 10% of the total molar amount of metal elements; and / or, The molar amount of Mn element in the solution accounts for 30% - 85% of the total molar amount of metal elements.

8. The method according to any one of claims 5 to 7, wherein, The temperature of the aging is 40°C - 98°C; and / or, The time of the aging is 10 - 500 min; and / or, The reaction and / or aging is carried out under the condition that the pH value is 1.5 - 4.5; and / or, The reaction and / or aging is carried out under stirring conditions.

9. The method according to any one of claims 5 to 8, wherein, The dissolution is carried out at 25°C - 80°C; and / or, The solvent is water; and / or, The filtration is negative pressure suction filtration, positive pressure filtration or centrifugal filtration; and / or, Before drying, the filter residue is washed, optionally washed with water; and / or, The temperature of the drying is 80°C - 500°C, optionally 120°C - 400°C, more optionally 150°C - 300°C; and / or, The time of the drying is 10 - 300 min.

10. A cathode material comprising the compound LiMn x Fe y M (1-x-y) PO 4 , wherein, 0.9 ≤ x + y < 1, 0 < x ≤ 0.9, 0 < y ≤ 0.9, M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, Group IVA metal elements, optionally includes one or more elements such as titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, europium; And, the preparation raw material of the positive electrode material includes the precursor material according to any one of claims 1 to 4 or the precursor material prepared by the method according to any one of claims 5 to 9.

11. A cathode material, comprising a core and a coating layer; the core comprises the compound LiMn x Fe y M (1-x-y) PO 4 ; wherein, 0.9 ≤ x + y < 1, 0 < x ≤ 0.9, 0 < y ≤ 0.9, M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, Group IVA metal elements, optionally includes one or more elements such as titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, europium; the coating layer includes carbon; And, the preparation raw material of the positive electrode material includes the precursor material according to any one of claims 1 to 4 or the precursor material prepared by the method according to any one of claims 5 to 9.

12. A method for preparing a positive electrode material, comprising the following steps: Mixing the precursor material according to any one of claims 1 to 4 or the precursor material prepared by the method according to any one of claims 5 to 9 and a lithium source in a solvent, grinding, drying, and sintering to obtain the positive electrode material; wherein, The positive electrode material includes the compound LiMn x Fe y M (1-x-y) PO 4 , where 0.9 ≤ x + y < 1, 0 < x ≤ 0.9, 0 < y ≤ 0.9, and the M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, and may be selected from one or more elements including titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium.

13. A method for preparing a positive electrode material, comprising the following steps: Mix the precursor material according to any one of claims 1 to 4 or the precursor material prepared by the method according to any one of claims 5 to 9, a lithium source, and a carbon source in a solvent, grind, dry, and sinter to obtain a cathode material; Wherein, The positive electrode material includes a core and a coating layer; the core includes the compound LiMn x Fe y M (1-x-y) PO 4 ; wherein, 0.9 ≤ x + y < 1, 0 < x ≤ 0.9, 0 < y ≤ 0.9, and M includes one or more of transition metal elements other than manganese and iron elements, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, and may be selected from one or more of titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium; the coating layer includes carbon.

14. According to the method of claim 12 or 13, Wherein, The compound Mn in the precursor material x Fe y M (1-x-y) HPO 4 ·nH 2 O and the lithium element in the lithium source have a molar ratio of 1:(1.0 - 1.1); and / or, The mass ratio of the precursor material to the carbon source is 1:(0.01 - 0.2); and / or, The Dv50 particle size of the insoluble matter in the mixture obtained after grinding is 0.1 - 7.0 μm, optionally 0.1 - 5.0 μm; and / or, The drying is carried out by a spray dryer, and the inlet air temperature of the spray dryer is 180°C - 350°C and the outlet air temperature is 90°C - 130°C; and / or, The temperature of the sintering is 450°C - 800°C; and / or, The time of the sintering is 6 - 20 h; and / or, Sintering is carried out in an inert atmosphere.

15. A cathode electrode sheet, comprising the cathode material according to claim 10 or 11 or the cathode material prepared by the method according to any one of claims 12 to 14.

16. A battery, comprising the cathode electrode sheet according to claim 15.

17. An electrical device, comprising the battery according to claim 16.

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