Precursor material and preparation method therefor, positive electrode material and preparation method therefor, positive electrode sheet, battery, and electric device

Abstract

A precursor material and a preparation method therefor, a positive electrode material and a preparation method therefor, a positive electrode sheet, a battery, and an electric device. The precursor material comprises a compound MnxFeyM(1-x-y)HPO4•nH2O, wherein 0.9≤x+y<1, 0<x≤0.9, 0<y≤0.9, 0≤n≤6, and M comprises one or more of transition metal elements other than manganese and iron elements, a group IIA metal element, a group IIIA metal element, and a group IVA metal element. Elements in the precursor material are uniformly distributed and have batch consistency, and elements in the prepared positive electrode material are uniformly distributed and have good batch consistency, so that the specific capacity and the cycle performance of the battery are improved.

Description

Precursor material and preparation method thereof, positive electrode material and preparation method thereof, positive electrode sheet, battery and electrical device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application 202311609836.7 filed on November 28, 2023, entitled “Precursor materials and preparation methods thereof, positive electrode materials and preparation methods thereof, positive electrode sheets, batteries and electrical devices,” and the entire contents of that application are incorporated herein by reference. Technical Field

[0003] The present application relates to the technical field of lithium batteries, and in particular to a precursor material, a method for preparing the precursor material, a positive electrode material, a method for preparing the positive electrode material, a positive electrode sheet, a battery, and an electrical device. Background Art

[0004] In recent years, the application of secondary batteries has become increasingly widespread. They are widely used in energy storage power systems such as hydropower, thermal power, wind power, and solar power stations, as well as in power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, and other fields. As secondary batteries have achieved great development, higher requirements have been placed on their energy density, cycle performance, and other aspects.

[0005] Summary of the Invention

[0006] This application is made in view of the above-mentioned problems, and its purpose is to provide a precursor material, a method for preparing the precursor material, a positive electrode material, a method for preparing the positive electrode material, a positive electrode sheet, a battery, and an electrical device. The elements in the precursor material of this application are evenly distributed and have good batch consistency. The elements in the prepared positive electrode material are evenly distributed and have good batch consistency, thereby improving the specific capacity and cycle performance of the prepared battery.

[0007] In order to achieve the above object, the first aspect of the present application provides a precursor material, including a compound Mn x Fe y M (1-x-y) HPO4·nH2O; wherein, 0.9≤x+y<1, 0<x≤0.9, 0<y≤0.9, 0≤n≤6; and M includes one or more of transition metal elements other than manganese and iron, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements.

[0008] 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 positive electrode material prepared using the precursor material of the present application are evenly distributed and have good batch consistency, thereby improving the electrical properties of the prepared battery such as specific capacity and cycle performance.

[0009] 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.

[0010] In any embodiment, M includes one or more elements selected from titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium.

[0011] 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,

[0012] The precursor material has a compaction density of 1.35-2.5 g / cm at 30 MPa. 3 and / or,

[0013] The compound Mn in the precursor material x Fe y M (1-x-y) The mass content of HPO4·nH2O is 98%-100%; and / or,

[0014] The precursor material includes primary crystal particles having a polyhedral morphology.

[0015] The Dv50 particle size of the precursor material of the present application is within the above-mentioned range. On the one hand, it is beneficial to the washing and filtering operations during the precursor preparation process, thereby improving the yield of the precursor material. On the other hand, when preparing the positive electrode material, it is beneficial to the suspension of the precursor particles and is not easy to settle, thereby improving the efficiency of the mixing and grinding processes.

[0016] The compaction density of the precursor material of the present application is within the above range, which is beneficial to increasing the compaction density of the positive electrode material, thereby improving the specific capacity of the battery.

[0017] The precursor material of the present application has a high compound content and a low impurity content, so the obtained positive electrode material has a low impurity content, and the specific capacity and cycle performance of the battery are improved.

[0018] The precursor material of the present application includes primary crystallized particles with a polyhedral morphology, whose crystal faces are flat and regular, and the interparticle gaps are smaller, which is conducive to improving the compaction density of the precursor material.

[0019] The second aspect of the present application also provides a method for preparing a precursor material, comprising the following steps:

[0020] dissolving a soluble manganese source, a soluble iron source, and a soluble source of the M element in a solvent to obtain a solution;

[0021] slowly adding the solution into a phosphoric acid solution to react, and optionally aging to obtain a reaction product;

[0022] Filtering the reaction product and drying the resulting filter residue to obtain a precursor material;

[0023] The precursor material includes compound Mn x Fe y M (1-x-y) HPO4·nH2O; wherein, 0.9≤x+y<1, 0<x≤0.9, 0<y≤0.9, 0≤n≤6; the M element includes one or more transition metal elements other than manganese and iron, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, and can be optionally one or more elements selected from titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium.

[0024] Therefore, the present application first prepares a soluble manganese source, a soluble iron source and a soluble M element source into a stable, homogeneous solution, and then slowly adds the solution to a phosphoric acid solution to control and reduce side reactions, and then obtains a precursor material with uniform composition, good batch consistency and low impurity content through optional aging and drying of the filtered residue. The elements in the positive electrode material prepared using the precursor material are evenly distributed and have good batch consistency, thereby improving the specific capacity and cycle performance of the battery.

[0025] In any embodiment, the soluble manganese source includes one or more of a soluble organic manganese source and a soluble inorganic manganese source, and may be a soluble organic manganese source, and may be one or more of a soluble organic acid salt of manganese, and may be one or more of manganous acetate, manganous formate, manganous citrate, and manganous 2-hydroxypropionate; and / or,

[0026] The soluble iron source includes one or more of a soluble organic iron source and a soluble inorganic iron source, and can be selected from a soluble organic iron source, and can be selected from one or more of a soluble organic acid salt of iron, and can further be selected from one or more of ferrous acetate, ferrous formate, ferrous citrate, and ferrous 2-hydroxypropionate; and / or,

[0027] 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, and can optionally include one or more of a soluble organic acid salt and a soluble inorganic acid salt of the M element, and can further optionally include one or more of sulfates, nitrates, chlorides, formates, acetates, citrates, and 2-hydroxypropionates of the M element.

[0028] 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 cycle performance of the battery.

[0029] In any embodiment, the solution is slowly added to a phosphoric acid solution for reaction at 25° C.-95° C.; and / or,

[0030] The solution addition time is 10-300 min, optionally 15-300 min, more optionally 60-180 min; and / or,

[0031] 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,

[0032] The total concentration of the 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,

[0033] The phosphoric acid concentration 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,

[0034] The molar amount of the M element in the solution accounts for 0.1%-10% of the total molar amount of the metal elements; and / or,

[0035] The molar amount of the Mn element in the solution accounts for 30% to 85% of the total molar amount of the metal elements.

[0036] The present application reduces side reactions by controlling the ambient temperature when the mixed metal solution is added to the phosphoric acid solution, so as 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.

[0037] The present application controls the rate at which the solution is added to the phosphoric acid solution, thereby helping to control and reduce side reactions, thereby preparing a precursor material with uniform composition, good batch consistency, and low impurity content, thereby improving the electrical performance of the battery.

[0038] The present application can improve the specific capacity of the battery by controlling the molar ratio of phosphoric acid to total metal elements.

[0039] The present application can adjust the molar ratio of each metal element in the precursor product by controlling the concentration of each metal element in the solution.

[0040] In any embodiment, the aging temperature is 40° C.-98° C.; and / or,

[0041] The aging time is 10-500 min; and / or,

[0042] Reaction and / or aging are carried out at a pH of 1.5-4.5; and / or,

[0043] The reaction and / or aging is carried out under stirring conditions.

[0044] 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 compaction density, thereby improving the specific capacity and cycle performance of the battery.

[0045] In any embodiment, the dissolving is performed at 25°C-80°C; and / or,

[0046] The solvent is water; and / or,

[0047] The filtration is negative pressure filtration, positive pressure filtration or centrifugal filtration; and / or,

[0048] Before drying, washing the filter residue, optionally by washing the filter residue with water; and / or,

[0049] The drying temperature is 80°C-500°C, optionally 120°C-400°C, more optionally 150°C-300°C; and / or,

[0050] The drying time is 10-300 minutes.

[0051] The third aspect of the present application provides a positive electrode material, including a compound LiMn x Fe y M (1-x-y) PO4, wherein 0.9≤x+y<1, 0<x≤0.9, 0<y≤0.9, and M includes one or more transition metal elements other than manganese and iron, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, and may be selected from one or more elements selected from titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium;

[0052] Furthermore, the raw materials for preparing the positive electrode 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.

[0053] The fourth aspect of the present application provides a positive electrode material, comprising a core and a coating layer; the core comprises the compound LiMn x Fe y M (1-x-y)PO4; wherein 0.9≤x+y<1, 0<x≤0.9, 0<y≤0.9, the M comprises one or more transition metal elements other than manganese and iron, group IIA metal elements, group IIIA metal elements, and group IVA metal elements, and may be selected from one or more elements selected from titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium; the coating layer comprises carbon;

[0054] Furthermore, the raw materials for preparing the positive electrode 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.

[0055] Therefore, the molar ratio of manganese, iron, doping elements and phosphorus in the precursor material of the present application is the same as that in the positive electrode material, thereby reducing the types of raw materials when preparing the positive electrode material, thereby improving the composition uniformity and batch consistency of the positive electrode material, and improving the specific capacity and cycle performance of the battery.

[0056] A fifth aspect of the present application provides a method for preparing a positive electrode material, comprising the following steps:

[0057] Mixing 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, grinding, drying, and sintering to obtain a positive electrode material;

[0058] Wherein, the positive electrode material includes the compound LiMn x Fe y M (1-x-y) PO4, wherein 0.9≤x+y<1, 0<x≤0.9, 0<y≤0.9, and M includes one or more transition metal elements other than manganese and iron, group IIA metal elements, group IIIA metal elements, and group IVA metal elements, and can be optionally one or more elements including titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium.

[0059] A sixth aspect of the present application provides a method for preparing a positive electrode material, comprising the following steps:

[0060] Mixing 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, grinding, drying, and sintering to obtain a positive electrode material;

[0061] 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)PO4; wherein, 0.9≤x+y<1, 0<x≤0.9, 0<y≤0.9, and M includes one or more transition metal elements other than manganese and iron, group IIA metal elements, group IIIA metal elements, and group IVA metal elements, and may be optionally one or more elements selected from titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium; and the coating layer includes carbon.

[0062] Therefore, the molar ratio of manganese, iron, doping elements and phosphorus in the precursor material of the present application is the same as that in the positive electrode material. Therefore, when preparing the positive electrode material, it is only necessary to react the precursor material with a lithium source and an optional carbon source, thereby reducing the types of raw materials, improving the composition uniformity and batch consistency of the positive electrode material, and improving the specific capacity and cycle performance of the battery.

[0063] In any embodiment, the compound Mn in the precursor material x Fe y M (1-x- y) The molar ratio of HPO4·nH2O to the lithium element in the lithium source is 1:(1.0-1.1); and / or,

[0064] The mass ratio of the precursor material to the carbon source is 1:(0.01-0.2); and / or,

[0065] 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,

[0066] The drying is performed by a spray dryer, wherein the air inlet temperature of the spray dryer is 180°C-350°C and the air outlet temperature of the spray dryer is 90°C-130°C; and / or,

[0067] The sintering temperature is 450°C-800°C; and / or,

[0068] The sintering time is 6-20h; and / or,

[0069] Sintered under inert atmosphere.

[0070] The insoluble matter in the mixture obtained after grinding reaches a certain Dv50 particle size, which is beneficial to increase the surface energy of the particles, improve the activity of the solid-solid reaction, shorten the diffusion path of lithium into the crystals of the precursor material, and make the reaction of generating the positive electrode material more complete, thereby improving the electrical performance of the battery.

[0071] The sintering temperature and sintering time adopted are conducive to making the reaction proceed more completely, thereby improving the electrical performance of the battery.

[0072] The seventh aspect of the present application provides a positive electrode plate, comprising the positive electrode material of the third or fourth aspect of the present application, or the positive electrode material prepared by the method of the fifth or sixth aspect of the present application.

[0073] The eighth aspect of the present application provides a battery, comprising the positive electrode plate of the seventh aspect of the present application.

[0074] The ninth aspect of the present application provides an electrical device comprising the battery of the eighth aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] FIG1 is a schematic diagram of a battery cell according to an embodiment of the present application.

[0076] FIG. 2 is an exploded view of the battery cell according to the embodiment of the present application shown in FIG. 1 .

[0077] FIG3 is a schematic diagram of a battery module according to an embodiment of the present application.

[0078] FIG4 is a schematic diagram of a battery pack according to an embodiment of the present application.

[0079] FIG. 5 is an exploded view of the battery pack shown in FIG. 4 according to an embodiment of the present application.

[0080] FIG6 is a schematic diagram of an electrical device using a battery cell as a power source according to an embodiment of the present application.

[0081] FIG7 is a flow chart of the method for preparing a precursor material in Example 1 of the present application.

[0082] FIG8 is a SEM photograph of the precursor material prepared in Example 1 of the present application.

[0083] FIG9 is a SEM photograph of the precursor material prepared in Comparative Example 3 of the present application.

[0084] FIG10 is an EDS image of lithium, manganese, iron, phosphorus, and cobalt elemental analysis of the positive electrode material prepared in Example 1 of the present application.

[0085] Explanation of reference numerals: 1 battery pack; 2 upper case; 3 lower case; 4 battery module; 5 battery cell; 51 housing; 52 electrode assembly; 53 top cover assembly. DETAILED DESCRIPTION

[0086] Hereinafter, the precursor material, the method for preparing the precursor material, the positive electrode material, the method for preparing the positive electrode material, the positive electrode sheet, the negative electrode sheet, the battery cell, the battery module, the battery pack and the embodiment of the electric device of the present application will be described in detail with appropriate reference to the accompanying drawings. However, there will be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the 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 described in the claims.

[0087] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0088] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0089] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0090] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, a method includes steps (a) and (b), which indicates that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, a method may further include step (c), which indicates that step (c) may 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 include steps (c), (a), and (b), etc.

[0091] Unless otherwise specified, the Dv50 particle size in this application refers to the particle size when the cumulative value of volume distribution is 50%.

[0092] [Battery Cell]

[0093] A battery cell, also known as a rechargeable battery or storage battery, refers to a battery that can be recharged to activate the active material after discharge and continue to be used.

[0094] Typically, a battery cell consists of a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte. During the battery's charge and discharge process, active ions (such as lithium ions) are embedded and released back and forth between the positive and negative electrode sheets. The separator is set between the positive and negative electrode sheets, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing active ions to pass through. The electrolyte between the positive and negative electrode sheets mainly plays the role of conducting active ions.

[0095] [Precursor materials]

[0096] One embodiment of the present application provides a precursor material including a compound Mn x Fe y M (1-x-y) HPO4·nH2O; wherein, 0.9≤x+y<1 (for example, x+y may be 0.9, 0.95, 0.99, 0.998, 0.999, 0.999, or a range consisting of any of the foregoing values), 0<x≤0.9 (for example, x may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or a range consisting of any of the foregoing values), 0<y≤0.9 (for example, y may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or a range consisting of any of the foregoing values), and 0≤n≤6 (for example, n may be 0, 1, 2, 3, 4, 5, or 6); and M includes one or more of transition metal elements other than manganese and iron, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements.

[0097] The conventional preparation method of element-doped lithium manganese iron phosphate positive electrode material is to prepare it by mechanically mixing multiple raw materials such as manganese source, iron source, lithium source, phosphorus source, and source of doping element, sand grinding to refine particles, spray drying, sintering and other processes; however, this method is prone to problems such as uneven composition, poor batch consistency and poor electrical performance.

[0098] Although the mechanism is still unclear, the applicant unexpectedly discovered that 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 positive electrode material prepared using the precursor material of the present application are evenly distributed and have good batch consistency, thereby improving the electrical properties of the prepared battery such as specific capacity and cycle performance.

[0099] 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.

[0100] In some embodiments, M includes one or more elements selected from the group consisting of titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium.

[0101] In some embodiments, the Dv50 particle size of the precursor material is 3-100 μm, optionally 5-50 μm, and more optionally 8-20 μm, for example, 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 a range consisting of any of the foregoing values.

[0102] The Dv50 particle size of the precursor material of the present application is within the above-mentioned range. On the one hand, it is beneficial to the washing and filtering operations during the precursor preparation process, thereby improving the yield of the precursor material. On the other hand, when preparing the positive electrode material, it is beneficial to the suspension of the precursor particles and is not easy to settle, thereby improving the efficiency of the mixing and grinding processes.

[0103] In the present application, the Dv50 particle size can be measured by conventional methods in the art, such as taking a sample and adding deionized water to completely disperse the sample, and measuring the Dv50 particle size using a laser particle size analyzer (MasterSizer 2000).

[0104] In some embodiments, the precursor material has a compacted density of 1.35-2.5 g / cm at 30 MPa. 3 , optional 1.5-2.5g / cm 3 , for example 1.35g / cm 3 , 1.5g / cm 3 , 1.7g / cm 3, 1.9g / cm 3 , 2.0g / cm 3 , 2.1g / cm 3 , 2.2g / cm 3 , 2.3g / cm 3 , 2.4g / cm 3 , 2.5g / cm 3 Or a range consisting of any of the foregoing numerical values.

[0105] The compaction density of the precursor material of the present application is within the above range, which is beneficial to increasing the compaction density of the positive electrode material, thereby improving the specific capacity of the battery.

[0106] In this application, the compaction density can be measured by conventional methods in the field. For example, the sample is placed in the mold of a compaction density tester. The tester automatically applies a pressure of 30 MPa to the powder until the powder 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 compaction density = mass / volume, the compaction density of the powder material can be measured.

[0107] In some embodiments, the compound Mn in the precursor material x Fe y M (1-x-y) The mass content of HPO4·nH2O is 98%-100%, such as 98.5%, 99%, 99.5%, 100% or any range consisting of the foregoing values.

[0108] The precursor material of the present application has a high compound content and a low impurity content, so the obtained positive electrode material has a low impurity content, and the specific capacity and cycle performance of the battery are improved.

[0109] In some embodiments, the precursor material includes primary crystallized particles having a polyhedral morphology.

[0110] The precursor material of the present application includes primary crystallized particles with a polyhedral morphology, whose crystal faces are flat and regular, and the interparticle gaps are smaller, which is conducive to improving the compaction density of the precursor material.

[0111] [Method for preparing precursor material]

[0112] One embodiment of the present application provides a method for preparing a precursor material, comprising the following steps:

[0113] dissolving a soluble manganese source, a soluble iron source, and a soluble source of the M element in a solvent to obtain a solution;

[0114] slowly adding the solution into a phosphoric acid solution to react, and optionally aging to obtain a reaction product;

[0115] Filtering the reaction product and drying the resulting filter residue to obtain a precursor material;

[0116] The precursor material includes compound Mn x Fe y M (1-x-y) HPO4·nH2O; 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 a range consisting 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 consisting 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 a range consisting 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 other than manganese and iron, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, and can be optionally one or more elements selected from titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium.

[0117] Phosphoric acid can dissociate into a variety of ions. The co-precipitation reaction between metal ions and ions dissociated from phosphoric acid is relatively complex, with many side reactions, and is prone to generate by-products such as gel-like, flocculent, and amorphous particles. The co-precipitate produced is 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.

[0118] Therefore, the present application first prepares a soluble manganese source, a soluble iron source and a soluble M element source into a stable, homogeneous solution, and then slowly adds the solution to a phosphoric acid solution to control and reduce side reactions, and then obtains a precursor material with uniform composition, good batch consistency and low impurity content through optional aging and drying of the filtered residue. The elements in the positive electrode material prepared using the precursor material are evenly distributed and have good batch consistency, thereby improving the specific capacity and cycle performance of the battery.

[0119] In some embodiments, the precursor material is the precursor material described above.

[0120] 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, and can be further optionally one or more of soluble organic acid salts of manganese, and can further be optionally one or more of manganous acetate, manganous formate, manganous citrate, and 2-hydroxymanganous propionate.

[0121] In some embodiments, the soluble iron source includes one or more of a soluble organic iron source and a soluble inorganic iron source, and can be optionally a soluble organic iron source, and can be more optionally one or more of a soluble organic acid salt of iron, and can further be optionally one or more of ferrous acetate, ferrous formate, ferrous citrate, and ferrous 2-hydroxypropionate.

[0122] 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 cycle performance of the battery.

[0123] In some embodiments, the source of the soluble M element includes one or more of an inorganic source of a soluble M element and an organic source of a soluble M element, and may optionally include one or more of a soluble organic acid salt and a soluble inorganic acid salt of the M element, and may further optionally include one or more of sulfates, nitrates, chlorides, formates, acetates, citrates, and 2-hydroxypropionates of the M element.

[0124] In some embodiments, the solution is slowly added to the phosphoric acid solution for reaction at 25°C-95°C, optionally 30°C-90°C (e.g., 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 consisting of any of the foregoing values).

[0125] The present application reduces side reactions by controlling the ambient temperature when the mixed metal solution is added to the phosphoric acid solution, so as 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.

[0126] In some embodiments, the addition time of the solution is 10-300 min, optionally 15-300 min, more optionally 60-180 min, further optionally 90-120 min, for example, 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 consisting of any of the foregoing values.

[0127] In some embodiments, 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, further optionally 0.9-1.1, for example, 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 consisting of any of the foregoing values.

[0128] The present application can improve the specific capacity of the battery by controlling the molar ratio of phosphoric acid to total metal elements.

[0129] In some embodiments, the total concentration of the 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, for example 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. 2mol / L, 1.3mol / L, 1.4mol / L, 1.5mol / L, 1.6mol / L, 1.7mol / L, 1.8mol / L, 1.9mol / L, 2.0mol / L, 2.1mol / L, 2.2mol / L, 2.3mol / L, 2.4mol / L, 2.5mol / L, 2.6mol / L, 2.8mol / L, 2.9mol / L, 3.0mol / L or a range consisting of any of the foregoing values.

[0130] 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, for example, 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 a range consisting of any of the foregoing values.

[0131] The present application controls the rate at which the solution is added to the phosphoric acid solution, thereby helping to control and reduce side reactions, thereby preparing a precursor material with uniform composition, good batch consistency, and low impurity content, thereby improving the electrical performance of the battery.

[0132] In some embodiments, the molar amount of the M element in the solution accounts for 0.1%-10% of the total molar amount of the metal elements, for example, 0.3%, 0.5%, 1%, 3%, 5%, 7%, 9%, 10% or a range consisting of any of the foregoing values.

[0133] In some embodiments, the molar amount of the Mn element in the solution accounts for 30% to 85% of the total molar amount of metal elements, for example, 35%, 40%, 45%, 50%, 55%, 58%, 60%, 65%, 70%, 75%, 80%, 85% or a range consisting of any of the foregoing values.

[0134] The present application can adjust the molar ratio of each metal element in the precursor product by controlling the concentration of each metal element in the solution.

[0135] In some embodiments, the aging temperature is 40°C-98°C, optionally 60°C-95°C, for example, 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 a range consisting of any of the foregoing values.

[0136] In some embodiments, the aging time is 10-500 min, optionally 30-300 min, for example, 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 a range consisting of any of the foregoing values.

[0137] In some embodiments, the reaction and / or aging is carried out at a pH of 1.5-4.5, for example, a pH of 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or a range consisting of any of the foregoing values.

[0138] In some embodiments, the reaction and / or aging is performed under stirring conditions.

[0139] 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 compaction density, thereby improving the specific capacity and cycle performance of the battery.

[0140] In some embodiments, the dissolving is performed at 25°C-80°C (e.g., 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 any range thereof); and / or,

[0141] The solvent is water.

[0142] In some embodiments, the filtration is negative pressure filtration, positive pressure filtration or centrifugal filtration.

[0143] In some embodiments, before drying, the filter residue is washed, optionally with water.

[0144] In some embodiments, the drying temperature is 80°C-500°C, optionally 120°C-400°C, and more optionally 150°C-300°C.

[0145] In some embodiments, the drying time is 10-300 min.

[0146] [Cathode material]

[0147] One embodiment of the present application provides a positive electrode material including a compound LiMn x Fe y M (1-x-y) PO4, wherein 0.9≤x+y<1 (for example, x+y may be 0.9, 0.95, 0.99, 0.998, 0.999, 0.999, or a range consisting of any of the foregoing values), 0<x≤0.9 (for example, x may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or a range consisting of any of the foregoing values), 0<y≤0.9 (for example, x may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or a range consisting of any of the foregoing values), and M includes one or more of transition metal elements other than manganese and iron, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, and may optionally include one or more elements selected from titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium;

[0148] Furthermore, the raw materials for preparing the positive electrode material include the precursor material mentioned above in this application or the precursor material prepared by the method mentioned above in this application.

[0149] 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)PO4; wherein, 0.9≤x+y<1 (for example, x+y may be 0.9, 0.95, 0.99, 0.998, 0.999, 0.999 or a range consisting of any of the foregoing values), 0<x≤0.9 (for example, x may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or a range consisting of any of the foregoing values), 0<y≤0.9 (for example, x may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or a range consisting of any of the foregoing values), the M comprises one or more of transition metal elements other than manganese and iron, Group IIA metal elements, Group IIIA metal elements, and Group IVA metal elements, and may be optionally one or more of titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium; the coating layer comprises carbon;

[0150] Furthermore, the raw materials for preparing the positive electrode material include the precursor material mentioned above in this application or the precursor material prepared by the method mentioned above in this application.

[0151] Therefore, the molar ratio of manganese, iron, doping elements and phosphorus in the precursor material of the present application is the same as that in the positive electrode material, thereby reducing the types of raw materials when preparing the positive electrode material, thereby improving the composition uniformity and batch consistency of the positive electrode material, and improving the specific capacity and cycle performance of the battery.

[0152] [Method for preparing positive electrode material]

[0153] One embodiment of the present application provides a method for preparing a positive electrode material, comprising the following steps:

[0154] Mixing the precursor material described above in this application or the precursor material prepared by the method described above in this application and a lithium source in a solvent, grinding, drying, and sintering to obtain a positive electrode material;

[0155] Wherein, the positive electrode material includes the compound LiMn x Fe y M (1-x-y) PO4, wherein 0.9≤x+y<1, 0<x≤0.9, 0<y≤0.9, and M includes one or more transition metal elements other than manganese and iron, group IIA metal elements, group IIIA metal elements, and group IVA metal elements, and can be optionally one or more elements including titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium.

[0156] Another embodiment of the present application provides a method for preparing a positive electrode material, comprising the following steps:

[0157] 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 are mixed in a solvent, ground, dried, and sintered to obtain a positive electrode material;

[0158] 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) PO4; wherein, 0.9≤x+y<1, 0<x≤0.9, 0<y≤0.9, and M includes one or more transition metal elements other than manganese and iron, group IIA metal elements, group IIIA metal elements, and group IVA metal elements, and may be optionally one or more elements selected from titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium; and the coating layer includes carbon.

[0159] Therefore, the molar ratio of manganese, iron, doping elements and phosphorus in the precursor material of the present application is the same as that in the positive electrode material. Therefore, when preparing the positive electrode material, it is only necessary to react the precursor material with a lithium source and an optional carbon source, thereby reducing the types of raw materials, improving the composition uniformity and batch consistency of the positive electrode material, and improving the specific capacity and cycle performance of the battery.

[0160] In some embodiments, the compound Mn in the precursor material x Fe y M (1-x- y) The molar ratio of HPO4·nH2O to the lithium element in the lithium source is 1:(1.0-1.1).

[0161] In some embodiments, the mass ratio of the precursor material to the carbon source is 1:(0.01-0.2), for example 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 consisting of any of the foregoing values.

[0162] 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, for example, 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 a range consisting of any of the foregoing values.

[0163] The insoluble matter in the mixture obtained after grinding reaches a certain Dv50 particle size, which is beneficial to increase the surface energy of the particles, improve the activity of the solid-solid reaction, shorten the diffusion path of lithium into the crystals of the precursor material, and make the reaction of generating the positive electrode material more complete, thereby improving the electrical performance of the battery.

[0164] In some embodiments, the drying is performed by a spray dryer, and the air inlet temperature of the spray dryer is 180°C-350°C and the air outlet temperature is 90°C-130°C.

[0165] In some embodiments, the sintering temperature is 450°C-800°C, for example, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C or any range thereof.

[0166] In some embodiments, the sintering time is 6-20 h, for example, 6 h, 8 h, 9 h, 10 h, 12 h, 14 h, 15 h, 17 h, 18 h, 19 h, 20 h or a range consisting of any of the foregoing values.

[0167] In some embodiments, sintering is performed under an inert atmosphere.

[0168] The sintering temperature and sintering time adopted are conducive to making the reaction proceed more completely, thereby improving the electrical performance of the battery.

[0169] [Positive electrode]

[0170] The positive electrode sheet generally includes a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector. The positive electrode film layer includes the aforementioned positive electrode material or the positive electrode material prepared by the aforementioned method.

[0171] The battery's charge and discharge processes involve the intercalation and deintercalation of lithium, leading to different molar Li contents at different discharge states. The molar Li contents listed in this application for cathode materials refer to the initial state of the material, i.e., the state before addition of the materials. When the cathode material is used in a battery system, the molar Li content will change after charge and discharge cycles.

[0172] In the list of positive electrode materials in this application, the molar content of O is only a theoretical value. Lattice oxygen release will cause the molar content of oxygen to change, and the actual molar content of O will fluctuate.

[0173] As an example, the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive electrode current collector.

[0174] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base. The composite current collector may be formed by forming a metal material (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.).

[0175] In some embodiments, as an example, the positive electrode material may also include the following materials: lithium transition metal oxides and modified compounds thereof. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), 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 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0176] 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), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin.

[0177] In some embodiments, the positive electrode film layer may further include a conductive agent. For 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.

[0178] In some embodiments, the positive electrode sheet can be prepared by the following method: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components, are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0179] [Negative electrode]

[0180] The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer provided on at least one surface of the negative electrode current collector, wherein the negative electrode film layer includes a negative electrode active material.

[0181] As an example, the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0182] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer base layer and a metal layer formed on at least one surface of the polymer base material. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer base material (such as a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0183] In some embodiments, the negative electrode active material may be a negative electrode active material for a battery that is 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. The silicon-based material may be selected from at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material 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 traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0184] In some embodiments, the negative electrode film layer may further include a binder. For 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).

[0185] In some embodiments, the negative electrode film layer may further include a conductive agent. For 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.

[0186] In some embodiments, the negative electrode film layer may optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0187] In some embodiments, the negative electrode sheet can be prepared by the following method: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components, are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0188] [Electrolytes]

[0189] The electrolyte conducts ions between the positive and negative electrodes. This application does not specify the type of electrolyte, and the electrolyte can be selected based on the needs. For example, the electrolyte can be liquid, gel, or solid.

[0190] In some embodiments, the electrolyte is liquid and includes an electrolyte salt and a solvent.

[0191] In some embodiments, the electrolyte salt may 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 difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0192] 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, methylpropyl carbonate, ethylpropyl 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, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.

[0193] In some embodiments, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, and additives that improve battery high or low temperature performance.

[0194] [Isolation film]

[0195] In some embodiments, the battery cell further includes a separator. The present application has no particular limitation on the type of separator, and any known porous separator with good chemical and mechanical stability can be selected.

[0196] In some embodiments, the material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0197] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator can be formed into an electrode assembly through a winding process or a lamination process.

[0198] In some embodiments, the battery cell may include an outer packaging that can be used to encapsulate the electrode assembly and the electrolyte.

[0199] In some embodiments, the outer packaging of the battery cell may be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. Alternatively, the outer packaging of the battery cell may be a soft shell, such as a pouch-type soft shell. The soft shell may be made of plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0200] The present application has no particular limitation on the shape of the battery cell, which can be cylindrical, square, or any other shape. For example, FIG1 shows a battery cell 5 with a square structure as an example.

[0201] In some embodiments, referring to Figure 2, the outer packaging may include a shell 51 and a cover plate 53. The shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can be formed into an electrode assembly 52 through a winding process or a lamination 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.

[0202] In some embodiments, battery cells may be assembled into a battery module. The battery module may contain one or more battery cells. The specific number may be selected by those skilled in the art based on the application and capacity of the battery module.

[0203] FIG3 shows an example battery module 4. Referring to FIG3 , within the battery module 4, multiple battery cells 5 may be arranged sequentially along the length of the battery module 4. Of course, they may also be arranged in any other manner. Furthermore, the multiple battery cells 5 may be secured together using fasteners.

[0204] Optionally, the battery module 4 may further include a housing having an accommodation space, and the plurality of battery cells 5 are accommodated in the accommodation space.

[0205] In some embodiments, the battery modules described above may also be assembled into a battery pack. The battery pack may contain one or more battery modules, and the specific number may be selected by those skilled in the art based on the application and capacity of the battery pack.

[0206] Figures 4 and 5 illustrate an example battery pack 1. Referring to Figures 4 and 5 , the battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box comprises an upper case 2 and a lower case 3. The upper case 2 can be placed over the lower case 3 to form an enclosed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0207] 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 in the present application. The battery cells, battery modules, or battery packs can be used as power sources for the electrical device, or as energy storage units for the electrical device. The electrical device may 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 and satellites, energy storage systems, etc., but is not limited thereto.

[0208] As an electrical device, a battery cell, battery module or battery pack can be selected according to its usage requirements.

[0209] Figure 6 shows an example of an electric device. This device is a pure electric vehicle, hybrid electric vehicle, or plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of the battery cells, a battery pack or battery module can be used.

[0210] [Example]

[0211] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0212] Example 1

[0213] (1) Preparation of precursor materials (as shown in Figure 7):

[0214] According to the molar ratio of Mn:Fe:Co of 0.597:0.398:0.005, 2.866 mol of manganous acetate, 1.910 mol of ferrous acetate, and 0.024 mol of cobalt sulfate were added to a stirring tank, and pure water was added to stir and dissolve according to the total metal ion molar concentration of 1.60 mol / L. The stirring function and the water bath heating function were turned on, and the liquid was heated to 40°C for insulation. After the powder was completely dissolved, 3.0 L of metal salt solution was obtained for use.

[0215] According to the above-mentioned total metal ion to phosphorus molar ratio of 1:1.100, 5.280 mol of concentrated phosphoric acid with a solute mass concentration of 85% was placed in a stirring tank, and pure water was added according to the molar concentration of the phosphoric acid solution of 1.32 mol / L and stirred evenly. The water bath heating function was turned on and the feed liquid was heated to 60°C and kept warm to obtain 4.0 L of phosphoric acid solution for use.

[0216] Maintaining the phosphoric acid solution in a water bath at 60°C, the metal salt solution was uniformly added to the phosphoric acid solution using a metering pump while stirring, allowing mixing and reaction. The volumetric flow rate of the metal salt solution was set at approximately 0.03 L / min, and the time required for complete addition of the solution was controlled within 100 minutes. After the addition was completed, the solution was heated to 85°C while stirring and aged for 120 minutes to complete the reaction and obtain a slurry. The system pH during the addition, reaction, and aging processes was measured using an online pH meter and was found to be 2-3.

[0217] The slurry was transferred to a vacuum filtration device with a maximum vacuum pressure of -0.06 MPa, and the solid precipitate was collected by filtration; about 3.6 L of pure water was added for online washing to obtain a precursor filter cake; the precursor filter cake was transferred to a blast drying oven, the drying temperature was set to 150 ° C, and dried for 120 minutes. At this time, the material was basically constant weight, and the precursor material was obtained.

[0218] (2) Preparation of positive electrode materials:

[0219] According to the molar ratio of the compound in the precursor material to the lithium element in the lithium source of 1:1, 510.28g of precursor material (the mass fraction of the compound in the precursor material is 99.0%, and the amount of substance is 3.000mol) and 110.84g of lithium carbonate (the amount of substance of the lithium element in the lithium carbonate is 3.000mol) were weighed; and according to the mass ratio of the precursor material to the carbon source of 1:0.12, 61.23g of glucose was weighed, and the above materials were added together to 1443.36g of pure water and mixed evenly, and then placed in a ball mill and ground to a particle size Dv50 of 0.8μm to obtain a slurry; the slurry was dried by spray drying with an air inlet temperature of 220°C and an air outlet temperature of 105°C to obtain a powder; the powder was sintered at 700°C for 12h in a nitrogen atmosphere in an atmosphere box furnace to obtain a positive electrode material.

[0220] (3) Preparation of positive electrode sheet:

[0221] Using an analytical balance (accuracy 0.0001g), weigh 0.3000g of polyvinylidene fluoride (PVDF) binder in 10.8g of N-methylpyrrolidone (NMP) and stir until completely dissolved. Then, add 2.4000g of the aforementioned positive electrode material and 0.3000g of carbon black conductive agent (SP) and stir until a paste is formed. The paste is evenly coated onto aluminum foil using an applicator and dried in a vacuum oven to remove the NMP solvent. After rolling and punching, a 16.0mm diameter disc is obtained to serve as the positive electrode sheet.

[0222] (4) Negative electrode: Metal lithium sheet is used.

[0223] (5) Isolation film: PE-PP composite film.

[0224] (6) Preparation of electrolyte:

[0225] Ethylene carbonate (EC) and dimethyl carbonate (DMC) were mixed in a volume ratio of 1:1, and then LiPF6 was uniformly dissolved in the above solution to obtain an electrolyte solution. The concentration of LiPF6 in the electrolyte solution was 1 mol / L.

[0226] (7) Preparation of button cells:

[0227] The positive electrode sheet, separator, negative electrode sheet and electrolyte were assembled into a CR2032 button battery.

[0228] The battery preparation methods of Examples 2-33 and Comparative Examples 1-2 are similar to those of Example 1. The different preparation methods and product parameters are detailed in Tables 1-3.

[0229] Example 32

[0230] (1) Preparation of precursor materials:

[0231] According to the molar ratio of Mn:Fe:Co of 0.597:0.398:0.005, 2.866 mol of manganous acetate, 1.910 mol of ferrous acetate, and 0.024 mol of cobalt sulfate were added to the stirring tank, and pure water was added according to the total metal ion molar concentration of 1.60 mol / L. Stir and dissolve, and turn on the water bath heating function to heat the liquid to 40°C for insulation. After the powder is completely dissolved, 3.0 L of metal salt solution is obtained for use.

[0232] According to the above-mentioned total metal ion to phosphorus molar ratio of 1:1.100, 5.280 mol of concentrated phosphoric acid with a solute mass concentration of 85% was placed in a stirring tank, and pure water was added according to the molar concentration of the phosphoric acid solution of 1.32 mol / L and stirred evenly. The water bath heating function was turned on and the feed liquid was heated to 60°C and kept warm to obtain 4.0 L of phosphoric acid solution for use.

[0233] The water bath temperature of the phosphoric acid solution was maintained at 60°C. The metal salt solution was added to the phosphoric acid solution at once under stirring and mixed for reaction. The pH value of the mixed slurry during the addition and reaction was measured using an online pH meter and was 2-3.

[0234] The slurry was transferred to a vacuum filtration device with a maximum vacuum pressure of -0.06 MPa, and the solid precipitate was collected by filtration; about 3.6 L of pure water was added for online washing to obtain a precursor filter cake; the precursor filter cake was transferred to a blast drying oven, the drying temperature was set to 150 ° C, and dried for 120 minutes. At this time, the material was basically constant weight, and the precursor material was obtained.

[0235] Steps (2) to (7) are the same as steps (2) to (7) in Example 1.

[0236] Example 33

[0237] (1) Preparation of precursor materials:

[0238] According to the molar ratio of Mn:Fe:Co of 0.597:0.398:0.005, 3.582 mol of manganese chloride, 2.388 mol of ferrous chloride, and 0.030 mol of cobaltous chloride were added to the stirring tank, and pure water was added according to the total metal ion molar concentration of 1.6 mol / L. Stir and dissolve, and turn on the water bath heating function to heat the liquid to 40°C for insulation. After the powder is completely dissolved, 6.0 L of metal salt solution is obtained for use.

[0239] According to the above-mentioned total metal ion to phosphorus molar ratio of 1:1.1, 7.2 mol of disodium hydrogen phosphate was placed in a stirring tank, and pure water was added according to the molar concentration of the disodium hydrogen phosphate solution of 1.0 mol / L. The mixture was stirred and dissolved, and the water bath heating function was turned on to heat the liquid to 60°C and keep it warm to prepare 7.2 L of phosphorus source solution for use.

[0240] The phosphorus source solution was maintained at a water bath temperature of 60°C. The metal salt solution was uniformly added to the phosphorus source solution using a metering pump while stirring, allowing mixing and reaction. The volume flow rate of the metal salt solution was set at approximately 0.06 L / min, and the addition time was controlled to be complete within 100 minutes. The pH of the mixed slurry during the addition and reaction process was measured using an online pH meter to be 4-6.

[0241] The slurry was transferred to a vacuum filtration device with a maximum vacuum pressure of -0.06 MPa, and the solid precipitate was collected by filtration; about 3.6 L of pure water was added for online washing to obtain a precursor filter cake; the precursor filter cake was transferred to a blast drying oven, the drying temperature was set to 300 ° C, and dried for 120 minutes. At this time, the material was basically constant weight, and the precursor material was obtained.

[0242] (2) Preparation of positive electrode materials:

[0243] According to the molar ratio of the compound in the precursor material to the lithium element in the lithium source of 1:1, 516.01g of the precursor material (the mass fraction of the compound in the precursor material is 97.90%, and the amount of substance is 3.000mol) and 110.84g of lithium carbonate (the amount of substance of the lithium element in the lithium carbonate is 3.000mol) were weighed; and according to the mass ratio of the precursor material to the carbon source of 1:0.12, 61.92g of glucose was weighed, and the above materials were added together to 1443.36g of pure water and mixed evenly, and then placed in a ball mill and ground to a particle size Dv50 of 0.8μm to obtain a slurry; the slurry was dried by spray drying with an air inlet temperature of 220°C and an air outlet temperature of 105°C to obtain a powder; the powder was sintered at 700°C for 12h in a nitrogen atmosphere in an atmosphere box furnace to obtain a positive electrode material.

[0244] Steps (3) to (7) are the same as steps (3) to (7) in Example 1.

[0245] Comparative Example 1

[0246] (1) Preparation of positive electrode materials

[0247] According to the molar ratio of Li:Mn:Fe:Co:PO4 of 1.000:0.597:0.398:0.005:1.000, 2.400 mol of lithium carbonate and 4.800 mol of concentrated phosphoric acid with a solute mass concentration of 85% were first added to 5945.63 g of pure water for mixed reaction to obtain a lithium dihydrogen phosphate solution, and then 2.866 mol of manganous oxalate, 1.910 mol of ferrous oxalate, 0.024 mol of cobaltous oxalate, and 61.23 g of glucose were added and mixed evenly. The mixture was placed in a ball mill and ground to a particle size Dv50 of 0.8 μm to obtain a slurry; the slurry was dried by spray drying with an air inlet temperature of 220°C and an air outlet temperature of 105°C to obtain a powder; the powder was sintered at 700°C for 12 hours in an atmosphere box furnace under a nitrogen atmosphere to obtain a positive electrode material.

[0248] Steps (2)-(6) are the same as steps (3)-(7) of Example 1.

[0249] Material testing and battery testing

[0250] (1) Testing of the mass fraction of each element and the chemical formula of the compound in the precursor and cathode material:

[0251] Weigh 0.2 g of 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, and then dilute to volume with a 100 mL volumetric flask; then use a pipette to transfer 1 mL to a 100 mL volumetric flask and dilute to volume to obtain the test solution.

[0252] The mass fractions of lithium, manganese, iron, phosphorus, and doping elements in the test solution were determined using an inductively coupled plasma optical emission spectrometer (ICP-OES, instrument brand: Agilent 5800). Based on the mass fractions of each element, the molar ratio of each element in the precursor material or cathode material was calculated to determine the chemical formula of the compound.

[0253] The mass content of the compound in the precursor material is calculated based on the measured mass fraction of phosphorus in the precursor material in combination with the above chemical formula.

[0254] (2) Dv50 particle size test:

[0255] Take an appropriate amount of 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.

[0256] (3) Evaluation of micromorphology and micro-area element distribution:

[0257] The microstructures of the precursor materials of Example 1 and Comparative Example 3 were observed using a scanning electron microscope (SEM, instrument brand: ZEISS sigma 300).

[0258] As shown in FIG8 , the precursor material of Example 1 is a primary crystal particle with a polyhedral morphology, with flat and regular crystal faces and few amorphous, honeycomb, and dendritic crystals, indicating that the precursor material has a high degree of crystallinity.

[0259] As shown in FIG9 , the precursor material obtained in Comparative Example 3 has an uneven microscopic morphology. It is not only needle-shaped but also has large particles with uneven particle sizes. In addition, no obvious crystal planes are observed, which suggests that an amorphous precursor material is formed.

[0260] The element distribution of lithium, manganese, iron, phosphorus and doping element cobalt in the micro area of ​​the positive electrode material obtained in Example 1 was characterized by an energy dispersive X-ray spectrometer (EDS).

[0261] As shown in FIG10 , the elements in the positive electrode material of Example 1 are distributed relatively evenly.

[0262] (4) Compaction density test:

[0263] Weigh 0.6000g of precursor material and place it in the compaction density tester mold. The tester automatically applies 30MPa of pressure to the powder until the powder is compacted. The volume of the powder can be calculated based on the cross-sectional area of ​​the mold and the thickness of the powder at this time. According to the compaction density = mass / volume, the compaction density of the powder material can be measured.

[0264] (5) Test of battery discharge capacity:

[0265] Shenzhen Xinweier battery testing system was used to cycle the button battery at a charge and discharge rate of 0.1C for 10 times. The test temperature was 25.0℃, and the charge and discharge voltage was 2.0V~4.3V. 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 positive electrode material on the electrode.

[0266] (6) Test of battery cycle capacity retention rate:

[0267] Shenzhen Xinweier battery testing system was used to cycle button batteries at a charge and discharge rate of 1.0C for 100 cycles. The test temperature was 25.0℃, and the charge and discharge voltage was 2.0V~4.3V. The percentage of the 50th discharge capacity to the first discharge capacity is the cycle capacity retention rate.

[0268] The test results are shown in Table 4.

[0269] Table 4: Performance test results of Examples 1-33 and Comparative Examples 1-2

[0270] According to the above results, we can know that:

[0271] Compared with Comparative Example 1 in which no precursor material was prepared and the positive electrode material was prepared by conventional methods, the specific capacity of the batteries of Examples 1-26 of the present application was significantly improved;

[0272] Compared with Comparative Example 2 which does not use the precursor material of the present application, the specific capacity and cycle capacity retention rate of the batteries of Examples 1-33 of the present application are significantly improved;

[0273] Compared with Example 32, in which the precursor material was prepared by adding the material once and without aging, the specific capacity of the batteries of Examples 1-26 of the present application was significantly improved;

[0274] Compared with the use of inorganic raw materials in preparing the precursor material in Example 33, the specific capacity and cycle capacity retention rate of the batteries in Examples 1-26 of the present application are significantly improved;

[0275] Compared with Example 22 using a lower precursor material compaction density, the battery specific capacity of Examples 1, 4-5 of the present application is higher;

[0276] Compared with the higher addition and reaction temperature used in preparing the precursor material in Example 23, the battery specific capacity and cycle capacity retention rate of Examples 1, 8-9 of the present application are higher;

[0277] Compared with the lower molar ratio of phosphoric acid to total metal elements used in preparing the precursor in Example 24, the battery specific capacity of Examples 1 and 10-13 of the present application is higher;

[0278] Compared with the lower aging temperature and longer aging time used in preparing the precursor material in Example 25, the specific capacity and cycle capacity retention rate of the batteries in Examples 1, 14-15 of the present application are higher; compared with the higher aging temperature and shorter aging time used in preparing the precursor material in Example 26, the specific capacity and cycle capacity retention rate of the batteries in Examples 1, 14-15 of the present application are higher;

[0279] Compared with the use of a larger insoluble matter Dv50 particle size after grinding when preparing the positive electrode material in Example 27, the specific capacity and cycle capacity retention rate of the batteries in Examples 1, 20-21 of the present application are higher;

[0280] Compared with Example 28 in which a smaller amount of carbon source is used to prepare the positive electrode material, the specific capacity and cycle capacity retention rate of the batteries in Examples 1 and 19 of the present application are higher.

[0281] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in 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) HPO4·nH2O; where 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, ⅡA group metal elements, ⅢA group metal elements, and ⅣA group metal elements.

2. The precursor material according to claim 1, wherein 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, wherein The M includes one or more elements selected from titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium.

4. The precursor material according to any one of claims 1 to 3, wherein The Dv50 particle size of the precursor material is 3-100 μm, optionally 5-50 μm, and more optionally 8-20 μm; and / or, The compacted density of the precursor material at 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) The mass content of HPO4·nH2O is 98%-100%; and / or, The precursor material includes primary crystal particles having a polyhedral morphology.

5. A method for preparing a precursor material, comprising the following steps: Dissolving a soluble manganese source, a soluble iron source and a soluble source of the M element in a solvent to obtain a solution; Slowly adding the solution into a phosphoric acid solution to react, and optionally aging to obtain a reaction product; Filtering the reaction product and drying the obtained filter residue to obtain a precursor material; The precursor material includes a compound Mn x Fe y M (1-x-y) HPO4·nH2O; 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, 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.

6. The method according to claim 5, wherein: The soluble manganese source includes one or more of a soluble organic manganese source and a soluble inorganic manganese source, and may be a soluble organic manganese source, and may be one or more of a soluble organic acid salt of manganese, and may be one or more of manganous acetate, manganous formate, manganous citrate, and manganous 2-hydroxypropionate; and / or, The soluble iron source includes one or more of a soluble organic iron source and a soluble inorganic iron source, and can be selected as a soluble organic iron source, and can be selected as one or more of a soluble organic acid salt of iron. Further optional is one or more of ferrous acetate, ferrous formate, ferrous citrate, and ferrous 2-hydroxypropionate; and / or, 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, and can be optionally one or more of a soluble organic acid salt and a soluble inorganic acid salt of the M element, and can be further optionally one or more of sulfates, nitrates, chlorides, formates, acetates, citrates, and 2-hydroxypropionates of the M element.

7. The method according to claim 5 or 6, wherein: At 25°C-95°C, slowly adding the solution into a phosphoric acid solution for reaction; and / or, The solution addition time 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, and more optionally 0.8-1.2; and / or, The total concentration of the metal elements in the solution is 0.1-3.0 mol / L, optionally 0.5-2.5 mol / L, more preferably 1.0-2.0 mol / L; and / or, The phosphoric acid concentration in the phosphoric acid solution is 0.1-3.0 mol / L, optionally 0.5-2.5 mol / L, more preferably 1.0-2.0 mol / L; and / or, The molar amount of the M element in the solution accounts for 0.1%-10% of the total molar amount of the metal elements; and / or, The molar amount of the Mn element in the solution accounts for 30% to 85% of the total molar amount of the metal elements.

8. The method according to any one of claims 5 to 7, wherein: The aging temperature is 40°C-98°C; and / or, The aging time is 10-500 min; and / or, Reaction and / or aging are carried out at a pH value of 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: Dissolving at 25°C-80°C; and / or, The solvent is water; and / or, The filtration is negative pressure filtration, positive pressure filtration or centrifugal filtration; and / or, Before drying, washing the filter residue, optionally by washing the filter residue with water; and / or, The drying temperature is 80°C-500°C, optionally 120°C-400°C, more preferably 150°C-300°C; and / or, The drying time is 10-300 minutes.

10. A positive electrode material comprising a compound LiMn x Fe y M (1-x-y) PO4, where 0.9≤x+y<1, 0<x≤0.9, 0<y≤0.9, the M 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, and may be selected from one or more of titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium; Furthermore, the raw material for preparing the positive electrode material includes the precursor material described in any one of claims 1 to 4 or the precursor material prepared by the method described in any one of claims 5 to 9.

11. A positive electrode material, comprising a core and a coating layer; the core comprises the compound LiMn x Fe y M (1-x-y) PO4; among them, 0.9≤x+y<1, 0<x≤0.9, 0<y≤0.9, the M 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 of titanium, magnesium, aluminum, vanadium, zinc, cobalt, nickel, tin, niobium, tungsten, zirconium, tantalum, cerium, and europium; the coating layer includes carbon; Furthermore, the raw material for preparing the positive electrode material includes the precursor material described in any one of claims 1 to 4 or the precursor material prepared by the method described in 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 a positive electrode material; in, The positive electrode material includes the compound LiMn x Fe y M (1-x-y) PO4, wherein 0.9≤x+y<1, 0<x≤0.9, 0<y≤0.9, and M 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, and may be selected from one or more of 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: 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, a lithium source, and a carbon source in a solvent, grinding, drying, and sintering to obtain a positive electrode material; in, The positive electrode material comprises a core and a coating layer; the core comprises the compound LiMn x Fe y M (1-x-y) PO4; wherein, 0.9≤x+y<1, 0<x≤0.9, 0<y≤0.9, the M comprises one or more of transition metal elements, ⅡA group metal elements, ⅢA group metal elements, and ⅣA group metal elements other than manganese and iron 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 comprises carbon.

14. The method according to claim 12 or 13, wherein: The compound Mn in the precursor material x Fe y M (1-x-y) The molar ratio of HPO4·nH2O to the lithium element in the lithium source is 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, and optionally 0.1-5.0 μm; and / or, The drying is performed by a spray dryer, wherein the air inlet temperature of the spray dryer is 180°C-350°C and the air outlet temperature of the spray dryer is 90°C-130°C; and / or, The sintering temperature is 450°C-800°C; and / or, The sintering time is 6-20h; and / or, Sintered in an inert atmosphere.

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

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

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

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