Positive electrode precursor and preparation method therefor, positive electrode material, and battery

Abstract

A positive electrode precursor and a preparation method therefor, a positive electrode material, and a battery. The preparation method comprises the following steps: adding a nickel-cobalt-manganese mixed salt solution, a dopant solution, a complexing agent solution and a precipitant solution into a base solution by means of concurrently flowing for a first-stage coprecipitation reaction, after a first target particle size is reached, stopping adding the nickel-cobalt-manganese mixed salt solution and the dopant solution, and adding a coating agent solution for a second-stage coprecipitation reaction to obtain a positive electrode precursor having the target particle size. In the process of preparing a precursor by means of coprecipitation, element doping and coating are carried out simultaneously, the present application is suitable for doping and coating of various elements, and the morphology, the doping amount, the particle size and the like of the precursor can be effectively regulated and controlled, so as to obtain a positive electrode precursor material having a stable structure, so that a positive electrode material has multiple properties.

Description

A positive electrode precursor and preparation method thereof, positive electrode material and battery Technical Field

[0001] The embodiments of the present application relate to the field of battery material technology, such as a positive electrode precursor and a preparation method thereof, a positive electrode material and a battery. Background Art

[0002] Currently, lithium-ion batteries and sodium-ion batteries are booming, but the material structure determines the material performance. Common lithium or sodium battery materials include NC, NCM, NM, NCA, etc. These materials need to be modified by doping or coating to achieve better electrochemical performance. Conventional doping technology is to dope or coat elements during the lithium calcination process of the precursor. The advantage of doping or coating in this process is that it is simple to operate and does not require consideration of the type of doping element. Basically, it can be effectively doped or coated, such as Al, Zr, W, Cr, Fe, etc.; and the above doping or coating processes are all achieved during the solid-phase sintering process.

[0003] Since doping or coating is performed by solid-phase sintering, only single-element doping or coating can be performed, and it is difficult to dope or coat more than two elements; or it is difficult to coat or dope specific structures; the solid-phase sintering method results in uncertain doping amount of each particle and uneven doping, and the doping amount of a single particle will also vary due to the morphology and size of the particles; the same is true for conventional solid-phase coating. Solid-phase mechanical mixing coating makes it difficult to accurately control the thickness of the coating layer and the uniformity of the coating layer, which makes it easy for the coating layer to fall off in the later stage, and ultimately leads to unstable electrochemical performance.

[0004] Therefore, how to improve the structural stability of the positive electrode material and achieve effective doping of multiple elements is a technical problem that needs to be solved urgently.

[0005] Summary of the Invention

[0006] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0007] The present invention provides a cathode precursor, a preparation method thereof, a cathode material, and a battery. The present invention simultaneously performs element doping and coating during the coprecipitation process to prepare the precursor. Multiple doping and coating elements are applicable, effectively regulating the precursor's morphology, doping level, and particle size, resulting in a structurally stable cathode precursor material, thereby achieving a multi-performance balance for the cathode material.

[0008] In a first aspect, an embodiment of the present application provides a method for preparing a positive electrode precursor, the preparation method comprising the following steps:

[0009] A nickel-cobalt-manganese mixed salt solution, a dopant solvent, a complexing agent solution and a precipitant solution are added to the base liquid in parallel to carry out a first-stage co-precipitation reaction. After reaching the first target particle size, the addition of the nickel-cobalt-manganese mixed salt solution and the dopant solution is stopped and replaced by the addition of the coating agent solution to carry out a second-stage co-precipitation reaction to obtain a positive electrode precursor with a target particle size.

[0010] The dopant solution provided in the present application may be a mixture of multiple doping elements added as a mixed dopant, or may be multiple dopant solutions added separately; adaptive adjustment may be made according to actual needs.

[0011] In the process of co-precipitation to prepare the precursor, the present application can directly carry out "combination coating and doping" of multiple elements in one step during the co-precipitation process to make up for the different application scenarios of the ternary material, so as to achieve the purpose of meeting both the cycle performance requirements and the rate requirements while ensuring the safety performance; at the same time, the morphology, doping amount and particle size of the precursor can be effectively regulated to obtain a structurally stable positive electrode precursor material, thereby achieving a multi-performance balance of the positive electrode material and improving the electrochemical performance of the battery.

[0012] Preferably, the dopant ions in the dopant solution include dopant cations and / or dopant anions, preferably dopant cations and dopant anions.

[0013] In the present application, cations and anions are doped simultaneously in the positive electrode precursor to maintain charge balance and structural stability without affecting the stability of the original metal elements.

[0014] Preferably, the doping cations include Na + Mg 2+ 、Al 3+ , K + , Ca 2+ 、Ti 4+ 、V 5+ 、Fe 2+ 、Fe 3+ 、Cu 2+ 、Zn 2+ 、Sn 4+ Sc 3+ 、Se 2+ 、Zr 4+ 、W 6+ 、Mo 6+ 、La 3+ 、Ce 3+ or Y 3+ Any one or a combination of at least two of .

[0015] The doping cation exists in the dopant solution in the form of a metal salt solution, such as nitrate, sulfate or chloride.

[0016] Preferably, the doping anion comprises F - 、Cl - , I - PO4 3- , BO2 - 、SiO4 4- 、CO3 2- or HCO3 - Any one or a combination of at least two of .

[0017] In the present application, the dopant anion is in the dopant, and when used as a separate doping source, it exists in the form of a solution.

[0018] In the present application, the doping anions are doped as a separate dopant solution rather than mixed with the mixed salt solution of the main element, because some anions will undergo precipitation reactions with metal ions. At the same time, in order to prevent mutual interference with the anions in the metal salt solution, separate doping can avoid the occurrence of the above problems and achieve better doping effects.

[0019] Preferably, the dopant solution further comprises an organic solution.

[0020] Preferably, the organic solution includes a urea solution.

[0021] In the present application, when the dopant solution is a urea solution, anions N and cations C can be doped simultaneously, thereby stabilizing the structure and improving the conductivity.

[0022] Preferably, the coating ions in the coating agent solution include Mg 2+ 、Al 3+ , Ca 2+ 、Ti 4+ 、V 5+ 、Fe 2+ 、Fe 3+ 、Cu 2+ 、Zn 2+ 、Sn 4+ Sc 3+ 、Se 2+ 、Zr 4+ 、W 6+ 、Mo 6+ 、La 3+ 、Ce 3+ or Y 3+ Any one or a combination of at least two of .

[0023] Preferably, the complexing agent solution includes any one of ammonia solution, oxalic acid solution, carbon ammonia solution, sodium oxalate solution, acetic acid solution, sodium acetate solution, EDTA solution or citric acid solution, or a combination of at least two thereof.

[0024] Preferably, the precipitant solution comprises any one or a combination of at least two of liquid alkali solution, sodium carbonate solution, sodium bicarbonate solution, carbon ammonia solution, oxalic acid solution, sodium oxalate solution, phosphoric acid solution, sodium phosphate solution, disodium hydrogen phosphate solution, sodium dihydrogen phosphate solution or sodium pyrophosphate solution.

[0025] Preferably, the reaction temperature of the first stage coprecipitation reaction and the second stage coprecipitation reaction is independently 30-70°C, for example, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C or 70°C.

[0026] Preferably, the pH value of the coprecipitation reaction in the first stage and the coprecipitation reaction in the second stage is 7 to 12, for example, 7, 7.3, 7.5, 7.8, 8, 8.3, 8.5, 8.8, 9, 9.3, 9.5, 9.8, 10, 10.3, 10.5, 10.8, 11, 11.3, 11.5, 11.8 or 12, etc.

[0027] Preferably, the reaction speed of the coprecipitation reaction in the first stage and the coprecipitation reaction in the second stage is 100-600 r / min, for example, 100 r / min, 200 r / min, 300 r / min, 400 r / min, 500 r / min or 600 r / min.

[0028] Preferably, the volume of the base liquid accounts for 20% to 80% of the total volume of the reactor used in the reaction process, for example, 20%, 30%, 40%, 50%, 60%, 70% or 80%.

[0029] Preferably, when the target particle size is greater than 5 μm, the difference between the particle size value of the target particle size and the particle size value of the first target particle size is ≤ 2 μm, for example, 0.5 μm, 0.8 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm or 2 μm, etc.

[0030] Preferably, when the target particle size is ≤5 μm, the difference between the particle size value of the target particle size and the particle size value of the first target particle size is ≤1 μm, for example, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm or 1 μm, etc.

[0031] In this application, when the target particle size is greater than 5 microns, the coating layer (the difference between the particle size value of the target particle size and the particle size value of the first target particle size) can be thicker, but if it exceeds 2 microns, it will lead to a decrease in electrochemical performance; and when the target particle size is less than or equal to 5 microns, the thickness of the coating layer is too thick, exceeding 1 micron, which will cause a decrease in electrochemical performance.

[0032] As a preferred technical solution, the preparation method comprises the following steps:

[0033] A nickel-cobalt-manganese mixed salt solution, a dopant solvent, a complexing agent solution, and a precipitant solution are added to a base solution in parallel, and a first-stage coprecipitation reaction is performed at 30-70° C. in an environment with a pH value of 7-12 at a reaction speed of 100-600 r / min. After reaching a first target particle size, the addition of the nickel-cobalt-manganese mixed salt solution and the dopant solution is stopped, and a coating agent solution is added instead. A second-stage coprecipitation reaction is performed at 30-70° C. in an environment with a pH value of 7-12 at a reaction speed of 100-600 r / min to obtain a cathode precursor with a target particle size.

[0034] The doping ions in the dopant solution are doping cations and doping anions, and the doping anions include F - 、Cl - , I - PO4 3- , BO2 - 、SiO4 4- 、CO3 2- or HCO3 - any one or a combination of at least two of the following; when the target particle size is greater than 5 μm, the difference between the particle size value of the target particle size and the particle size value of the first target particle size is ≤2 μm; when the target particle size is ≤5 μm, the difference between the particle size value of the target particle size and the particle size value of the first target particle size is ≤1 μm.

[0035] It should be noted that in the co-precipitation reaction process provided in this application, the feed amount, concentration, etc. of each solution can be adaptively adjusted according to the specific target particle size, doping amount and coating amount, without special limitation.

[0036] The base liquid in the co-precipitation process can be pure water or prepared by yourself according to actual needs.

[0037] As in the present application, the base liquid can be prepared by itself, by adding a complexing agent solution, a precipitant solution and pure water, and adjusting it according to a preset pH value.

[0038] In a second aspect, an embodiment of the present application provides a positive electrode precursor, which is prepared by the preparation method described in the first aspect; the positive electrode precursor includes a doped precursor core and a coating layer coated on the surface of the doped precursor core.

[0039] Preferably, the D50 of the positive electrode precursor is 2 to 19 μm, for example, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm or 19 μm.

[0040] In a third aspect, an embodiment of the present application provides a positive electrode material, which is obtained by mixing and sintering the positive electrode precursor as described in the second aspect with a lithium source or a sodium source.

[0041] In a fourth aspect, an embodiment of the present application further provides a battery, comprising the positive electrode material as described in the third aspect.

[0042] Preferably, the battery comprises a lithium-ion battery and / or a sodium-ion battery.

[0043] Compared with the related art, the embodiments of the present application have the following beneficial effects:

[0044] In the process of preparing the precursor by co-precipitation, the embodiment of the present application can directly carry out "combination coating and doping" of multiple elements in one step during the co-precipitation process to make up for the different application scenarios of the ternary material, so as to achieve the purpose of meeting both the cycle performance requirements and the rate requirements while ensuring the safety performance; at the same time, the morphology, doping amount and particle size of the precursor can be effectively regulated to obtain a positive electrode precursor material with stable structure, thereby achieving the multi-performance balance of the positive electrode material and improving the electrochemical performance of the battery.

[0045] Still other aspects will become apparent upon reading and understanding the detailed description. DETAILED DESCRIPTION

[0046] The technical solution of the present application is further illustrated below by specific examples. Those skilled in the art should understand that the examples are only for facilitating understanding of the present application and should not be regarded as specific limitations of the present application.

[0047] Example 1

[0048] This embodiment provides a positive electrode precursor, which includes a nickel-cobalt-manganese hydroxide core containing doping elements and a coating layer located on the surface of the core (the coating layer has a thickness of 2 μm); the chemical formula of the positive electrode precursor is Ni 77 Co3Mn 18 A2(OH) 1.5 B 0.5@C(OH)2 (where A is a doped cation element, which mainly occupies the transition metal layer and plays a supporting structure role; B is an anion that mainly occupies the skeleton layer of O and plays a role in stabilizing the structure through the covalent bond formed with O. C is a coating element).

[0049] The preparation method of the positive electrode precursor is as follows:

[0050] (1) preparing a nickel-cobalt-manganese mixed sulfate solution, a dopant solution, a sodium hydroxide solution, an ammonia solution, and a coating agent solution according to a preset positive electrode precursor;

[0051] Wherein, the dopant solution includes a cationic dopant solution (Ti 4+ 、V 5+ 、Fe 2+ 、Fe 3+ 、Cu 2+ , and Zn 2+ mixed sulfate solution) and anion dopant solution (sodium fluoride and diammonium hydrogen phosphate solution);

[0052] Coating agent solution (Mg 2+ 、Al 3+ , Ca 2+ 、Ti 4+ and V 5+ chloride salt solution);

[0053] (2) adding a nickel-cobalt-manganese mixed sulfate solution, a dopant solution, a sodium hydroxide solution, and an ammonia solution into a bottom liquid (prepared from ammonia water, liquid caustic soda, and pure water, ensuring that the pH value of the bottom liquid is 8; the volume of the bottom liquid is 30% of the total volume of the reactor) in parallel, and carrying out the first stage of coprecipitation reaction in an environment with a pH value of 8 at a stirring rate of 400 r / min and a reaction temperature of 40° C.;

[0054] When the particles grow to 8 μm, stop adding the nickel-cobalt-manganese mixed sulfate solution and the dopant solution and replace them with the coating agent solution. In an environment with a pH value of 8, carry out the second stage of coprecipitation reaction at a stirring rate of 400 r / min and a reaction temperature of 40°C until the particles reach the target particle size of 10 μm. Then stop the reaction, settle, remove the supernatant, wash and dry to obtain the positive electrode precursor.

[0055] Example 2

[0056] This embodiment provides a positive electrode precursor, which includes a nickel-cobalt-manganese hydroxide core containing doping elements and a coating layer located on the surface of the core (the coating layer has a thickness of 1 μm); the chemical formula of the positive electrode precursor is Ni 0.8 Co 0.1 Mn 0.08 M 0.02(OH)2@B(OH)2 (wherein, M includes a doping element and B includes a coating element).

[0057] The preparation method of the positive electrode precursor is as follows:

[0058] (1) preparing a nickel-cobalt-manganese mixed sulfate solution, a dopant solution, a sodium hydroxide solution, an ammonia solution, and a coating agent solution according to a preset positive electrode precursor;

[0059] Wherein, the dopant solution includes a cationic dopant solution (a mixed sulfate solution of aluminum and magnesium, with a molar ratio of aluminum to magnesium of 1:1);

[0060] Coating agent solution (zirconium chloride);

[0061] (2) adding a nickel-cobalt-manganese mixed sulfate solution, a dopant solution, a sodium hydroxide solution, and an ammonia solution into a bottom liquid (prepared from ammonia water, liquid caustic soda, and pure water, ensuring that the pH value of the bottom liquid is 9; the volume of the bottom liquid is 20% of the total volume of the reactor) in parallel, and carrying out the first stage of coprecipitation reaction at a stirring rate of 350 r / min and a reaction temperature of 60° C. in an environment with a pH value of 9;

[0062] When the particles grow to 4 μm, stop adding the nickel-cobalt-manganese mixed sulfate solution and the dopant solution and replace them with the coating agent solution. In an environment with a pH value of 9, carry out the second stage of coprecipitation reaction at a stirring rate of 350 r / min and a reaction temperature of 60°C until the particles reach the target particle size of 5 μm. Then stop the reaction, settle, remove the supernatant, wash and dry to obtain the positive electrode precursor.

[0063] Example 3

[0064] This embodiment provides a positive electrode precursor, which includes a nickel-cobalt-manganese hydroxide core containing doping elements and a coating layer located on the surface of the core (the coating layer has a thickness of 1.5 μm); the chemical formula of the positive electrode precursor is Ni 0.5 Co 0.2 Mn 0.29 N 0.01 (OH)2@B(OH)2 (wherein, M includes a doping element and B includes a coating element).

[0065] The preparation method of the positive electrode precursor is as follows:

[0066] (1) preparing a nickel-cobalt-manganese mixed sulfate solution, a dopant solution, a sodium hydroxide solution, an ammonia solution, and a coating agent solution according to a preset positive electrode precursor;

[0067] wherein the dopant solution comprises a urea solution;

[0068] Coating agent solution (cerium chloride);

[0069] (2) adding a nickel-cobalt-manganese mixed sulfate solution, a dopant solution, a sodium hydroxide solution, and an ammonia solution into a bottom liquid (prepared from ammonia water, liquid caustic soda, and pure water, ensuring that the pH value of the bottom liquid is 10; the volume of the bottom liquid is 40% of the total volume of the reactor) in parallel, and carrying out the first stage of coprecipitation reaction in an environment with a pH value of 10 at a stirring rate of 300 r / min and a reaction temperature of 55° C.;

[0070] When the particles grow to 15 μm, stop adding the nickel-cobalt-manganese mixed sulfate solution and the dopant solution and replace them with the coating agent solution. In an environment with a pH value of 10, carry out the second stage of coprecipitation reaction at a stirring rate of 300 r / min and a reaction temperature of 55°C until the particles reach the target particle size of 16.5 μm. Then stop the reaction, settle, remove the supernatant, wash and dry to obtain the positive electrode precursor.

[0071] Example 4

[0072] The difference between this embodiment and embodiment 1 is that the dopant solution provided in this embodiment does not include an anion dopant solution.

[0073] The rest of the preparation methods and parameters were the same as those in Example 1.

[0074] Example 5

[0075] The difference between this embodiment and embodiment 1 is that the thickness of the coating layer in this embodiment is 3 μm;

[0076] In the preparation method, after the particles grow to 7 μm, the addition of the nickel-cobalt-manganese mixed sulfate solution and the dopant solution is stopped, and the coating agent solution is added instead. The reaction is stopped when the particles reach the target particle size of 10 μm.

[0077] The rest of the preparation methods and parameters were the same as those in Example 1.

[0078] Example 6

[0079] The difference between this embodiment and embodiment 2 is that the thickness of the coating layer in this embodiment is 1.5 μm;

[0080] In the preparation method, after the particles grow to 3.5 μm, the addition of the nickel-cobalt-manganese mixed sulfate solution and the dopant solution is stopped, and the coating agent solution is added instead. The reaction is stopped when the particles reach the target particle size of 5 μm.

[0081] The rest of the preparation methods and parameters were the same as those in Example 2.

[0082] Comparative Example 1

[0083] The difference between this comparative example and Example 1 is that no doping or coating is performed in this comparative example, and the chemical formula of the positive electrode precursor is Ni 77 Co3Mn 20 (OH)2.

[0084] In the preparation method, no dopant solution and coating agent solution are added, and the coprecipitation reaction is carried out continuously until the target particle size of 10 μm is reached, and then the reaction is stopped.

[0085] The rest of the preparation methods and parameters were the same as those in Example 1.

[0086] Furthermore, positive electrode materials were prepared from the precursors provided in Examples 1-6 and Comparative Example 1.

[0087] Positive electrode materials provided in Examples 1-6: The positive electrode precursors provided in Examples 1-6 were mixed with lithium hydroxide respectively, and sintered at 850° C. for 6 h in an oxygen atmosphere to obtain positive electrode materials.

[0088] Positive electrode material provided in Comparative Example 1: The positive electrode precursor provided in Comparative Example 1, the dopant (completely consistent with the dopant in Example 1) and lithium hydroxide are mixed, and the mixture is sintered at 900°C in an oxygen atmosphere for 4 hours to obtain a fired material; the fired material is mixed with a coating agent (completely consistent with the coating agent in Example 1), and the mixture is sintered at 500°C for 4 hours to obtain a positive electrode material.

[0089] The positive electrode materials, superP, and PVDF provided in Examples 1-6 and Comparative Example 1 were mixed with an appropriate amount of NMP in a ratio of 95:3:2, evenly applied to aluminum foil, placed in a vacuum oven and dried at 180°C for 8 hours, and a pole piece with a diameter of 10 mm was prepared using a slicer. A lithium sheet was used as the counter electrode to obtain a button battery.

[0090] The batteries provided in Examples 1-6 and Comparative Example 1 were subjected to electrochemical performance tests. The test conditions were: 0.2C / 2C test rate performance (initial capacity), 0.2C / 0.2C charge and discharge 100 cycles test cycle performance (initial capacity). The test results are shown in Table 1.

[0091] Table 1

[0092] From the data results of Example 1 and Example 4, it can be seen that during the doping process, simultaneous doping of cations and anions can better improve the electrical conductivity of the material, thereby achieving higher rate performance.

[0093] From the data results of Example 1 and Example 5, and Example 2 and Example 6, it can be seen that within different target particle size ranges, if the thickness of the coating layer is too thick, the lithium ion diffusion performance will deteriorate, thereby significantly reducing the rate performance.

[0094] From the data results of Example 1 and Comparative Example 1, it can be seen that compared with the doping and coating performed by solid-phase sintering during the preparation of positive electrode materials, the present application provides a method for simultaneously achieving doping and coating during the co-precipitation preparation of precursors, which can better achieve multi-element doping and coating, improve structural stability, and thus improve the performance of positive electrode materials.

[0095] To sum up, in the process of co-precipitation to prepare the precursor, the present application can carry out "combination coating and doping" of multiple elements in one step during the co-precipitation process to make up for the different application scenarios of the ternary material, so as to achieve the purpose of meeting both the cycle performance requirements and the rate requirements while ensuring the safety performance; at the same time, the morphology, doping amount and particle size of the precursor can be effectively regulated to obtain a positive electrode precursor material with stable structure, thereby achieving the multi-performance of the positive electrode material and improving the electrochemical performance of the battery.

[0096] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of this application. It should be understood that the above is only a specific embodiment of this application and is not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

1. A method for preparing a positive electrode precursor, comprising the following steps: A nickel-cobalt-manganese mixed salt solution, a dopant solvent, a complexing agent solution and a precipitant solution are added to the base liquid in parallel to carry out a first-stage co-precipitation reaction. After reaching the first target particle size, the addition of the nickel-cobalt-manganese mixed salt solution and the dopant solution is stopped and replaced by the addition of the coating agent solution to carry out a second-stage co-precipitation reaction to obtain a cathode precursor of the target particle size.

2. The method for preparing a cathode precursor according to claim 1, wherein: The doping ions in the dopant solution include doping cations and / or doping anions, preferably doping cations and doping anions.

3. The method for preparing a cathode precursor according to claim 2, wherein: The doping cations include Na + Mg 2+ 、Al 3+ , K + , Ca 2+ 、Ti 4+ 、V 5+ , Fe 2+ , Fe 3+ , Cu 2+ 、Zn 2+ Sn 4+ Sc 3+ 、Se 2+ 、Zr 4+ , W 6+ 、Mo 6+ ,La 3+ 、Ce 3+ or Y 3+ Any one or a combination of at least two of the following.

4. The method for preparing a cathode precursor according to claim 2 or 3, wherein: The doping anions include F - , Cl - ,I - PO4 3- , BO2 - 、SiO4 4- 、CO3 2- or HCO3 - Any one or a combination of at least two of the following.

5. The method for preparing a cathode precursor according to any one of claims 2 to 4, wherein: The dopant solution also includes an organic solution; Preferably, the organic solution comprises a urea solution.

6. The method for preparing a cathode precursor according to any one of claims 1 to 5, wherein: The coating ions in the coating agent solution include Mg 2+ 、Al 3+ , Ca 2+ 、Ti 4+ 、V 5+ , Fe 2+ , Fe 3+ , Cu 2+ 、Zn 2+ Sn 4+ Sc 3+ 、Se 2+ 、Zr 4+ , W 6+ 、Mo 6+ ,La 3+ 、Ce 3+ or Y 3+ Any one or a combination of at least two of the following.

7. The method for preparing a cathode precursor according to any one of claims 1 to 6, wherein: The complexing agent solution includes any one of ammonia solution, oxalic acid solution, carbon ammonia solution, sodium oxalate solution, acetic acid solution, sodium acetate solution, EDTA solution or citric acid solution, or a combination of at least two thereof; Preferably, the precipitant solution comprises any one of a liquid alkali solution, a sodium carbonate solution, a sodium bicarbonate solution, a carbon ammonia solution, an oxalic acid solution, a sodium oxalate solution, a phosphoric acid solution, a sodium phosphate solution, a disodium hydrogen phosphate solution, a sodium dihydrogen phosphate solution or a sodium pyrophosphate solution, or a combination of at least two thereof.

8. The method for preparing a cathode precursor according to any one of claims 1 to 7, wherein: The reaction temperatures of the first stage coprecipitation reaction and the second stage coprecipitation reaction are independently 30 to 70° C.; Preferably, the pH value of the coprecipitation reaction in the first stage and the coprecipitation reaction in the second stage is 7 to 12; Preferably, the reaction speed of the coprecipitation reaction in the first stage and the coprecipitation reaction in the second stage is 100 to 600 r / min; Preferably, the volume of the base liquid accounts for 20-80% of the total volume of the reaction kettle used in the reaction process.

9. The method for preparing a cathode precursor according to any one of claims 1 to 8, wherein: When the target particle size is greater than 5 μm, the difference between the particle size value of the target particle size and the particle size value of the first target particle size is ≤ 2 μm; Preferably, when the target particle size is ≤5 μm, the difference between the particle size value of the target particle size and the particle size value of the first target particle size is ≤1 μm.

10. The method for preparing a cathode precursor according to any one of claims 1 to 9, comprising the following steps: A nickel-cobalt-manganese mixed salt solution, a dopant solvent, a complexing agent solution and a precipitant solution are added to the base solution in parallel, and a first-stage coprecipitation reaction is performed at 30 to 70° C. in an environment with a pH value of 7 to 12 at a reaction speed of 100 to 600 r / min. After reaching a first target particle size, the addition of the nickel-cobalt-manganese mixed salt solution and the dopant solution is stopped, and replaced by adding a coating agent solution, and a second-stage coprecipitation reaction is performed at 30 to 70° C. in an environment with a pH value of 7 to 12 at a reaction speed of 100 to 600 r / min to obtain a positive electrode precursor with a target particle size; The doping ions in the dopant solution are doping cations and doping anions, and the doping anions include F - , Cl - ,I - PO4 3- , BO2 - 、SiO4 4- 、CO3 2- or HCO3 - any one or a combination of at least two of the following; when the target particle size is greater than 5 μm, the difference between the particle size value of the target particle size and the particle size value of the first target particle size is ≤2 μm; when the target particle size is ≤5 μm, the difference between the particle size value of the target particle size and the particle size value of the first target particle size is ≤1 μm.

11. A cathode precursor, wherein: The positive electrode precursor is prepared by the preparation method according to any one of claims 1 to 10; the positive electrode precursor comprises a doped precursor core and a coating layer coated on the surface of the doped precursor core.

12. The cathode precursor according to claim 11, wherein The D50 of the positive electrode precursor is 2 to 19 μm.

13. A positive electrode material, wherein: The positive electrode material is obtained by mixing and sintering the positive electrode precursor as claimed in claim 11 or 12 with a lithium source or a sodium source.

14. A battery, wherein: The battery comprises the positive electrode material as claimed in claim 13.

15. The battery according to claim 14, wherein The battery includes a lithium ion battery and / or a sodium ion battery.

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