Doped lithium-rich manganese-based precursor, preparation method thereof, positive electrode material and battery

Abstract

The invention provides a doped lithium-rich manganese-based precursor, a preparation method thereof, a positive electrode material and a battery, and relates to the technical field of preparation of battery positive electrode materials. Fluorine and phosphorus doped elements are synchronously added in the precursor synthesis process and can be uniformly dispersed in the precursor, the nucleation and growth modes of the precursor are induced by utilizing the adsorption characteristics and the synergistic induction effect of the fluorine and phosphorus elements, and the precursor morphology with needle-shaped radial arrangement is synthesized. The lithium-rich material with the corresponding morphology is beneficial to migration and transmission of lithium ions from the inside to the outside of the material on one hand, meanwhile, the stress is small, and the structure is more stable in the circulation process.

Description

Technical Field

[0001] The present invention relates to the technical field of battery positive electrode material preparation, and in particular to a doped lithium-rich manganese-based precursor, a preparation method thereof, a positive electrode material and a battery. Background Art

[0002] With the development of electric vehicles, large-scale energy storage and micro devices, there is a constant demand to further improve the energy density, power density, cycle life and safety of existing secondary batteries, and reduce costs. The positive electrode material is a key factor in determining the energy density, safety performance and cost of batteries. Due to its unique electrochemical reaction mechanism, lithium-rich manganese-based positive electrode materials can release a much higher discharge capacity (greater than 250mAh / g) than existing conventional positive electrode materials, and have significant advantages such as high voltage, good thermal stability and low raw material prices. This has made it a research hotspot recently and is considered to be one of the most promising positive electrode materials for future high-energy lithium batteries. However, lithium-rich materials have problems such as low lithium ion diffusion coefficient, structural phase change caused by oxygen evolution during high-voltage cycling, and transition metal dissolution, which leads to poor cycle performance, especially high-temperature cycle performance, and rapid attenuation of discharge voltage with phase change. These are all intrinsic problems that restrict its commercialization.

[0003] To overcome the above problems, the existing technology mainly uses element doping and surface coating to improve the electrochemical performance of lithium-rich materials. Patent CN 112234176 A adds magnesium and fluorine to the carbonate precursor to achieve doping, which can effectively improve the crystal stability of lithium-rich materials and inhibit voltage decay. However, the carbonate precursor is not completely precipitated, the decomposition rate is high during sintering, the material has a high specific surface area, and the compaction density is low.

[0004] At the same time, the morphology and physical properties of the precursor are also key factors affecting the performance of lithium-rich materials. At present, the conventional hydroxide co-precipitation method is usually used to synthesize lithium-rich precursors. Due to the high manganese content, the primary particles of the precursor tend to form thick and large hexagonal flakes. This large primary particle morphology is difficult to be lithiated during sintering. Moreover, since the sintering material inherits the morphology of the precursor, the primary particles of the sintering material are also thick and large, the lithium ion diffusion path is long, and the electrochemical properties such as capacity utilization and rate performance are not ideal.

[0005] Therefore, it is necessary to develop a simple and effective method to improve the electrochemical properties of lithium-rich materials and regulate the morphology of primary particles of lithium-rich precursors. Summary of the invention

[0006] The present invention simultaneously adds fluorine and phosphorus doping elements during the precursor synthesis process, which can be evenly dispersed in the precursor. The fluorine element has a high electronegativity and has a strong bonding effect with the transition metal, which can effectively stabilize the bulk phase and surface structure of the material, and has a good improvement on the material's cycle stability and pressure drop; the phosphorus element forms Li3PO4 with lithium during the high-temperature lithiation sintering process of the precursor, which has a high lithium ion diffusion coefficient, provides a rapid diffusion channel for lithium ions, reduces the impedance of lithium-rich materials, and improves the material's rate performance and electrochemical performance. At the same time, the adsorption characteristics and synergistic induction of fluorine and phosphorus elements are used to induce the nucleation and growth mode of the precursor, and a precursor morphology with a needle-like radial orientation is synthesized. Due to the inheritance of the material to the precursor, the lithium-rich material corresponding to this morphology is conducive to the migration and transmission of lithium ions from the inside to the outside of the material, and at the same time, the stress is small, and the structure is more stable during the cycle.

[0007] One of the objectives of the present invention is to provide a doped lithium-rich manganese-based precursor.

[0008] The second object of the present invention is to provide a method for preparing the doped lithium-rich manganese-based precursor.

[0009] The third object of the present invention is to provide a positive electrode material prepared from the doped lithium-rich manganese-based precursor.

[0010] A fourth object of the present invention is to provide a battery comprising the positive electrode material.

[0011] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0012] In a first aspect, the present invention provides a doped lithium-rich manganese-based precursor, wherein the doped lithium-rich manganese-based precursor is nickel manganese hydroxide or nickel cobalt manganese hydroxide doped with fluorine and phosphorus elements;

[0013] The doped lithium-rich manganese-based precursor is a secondary spherical or quasi-spherical particle composed of primary particles. The primary particles are needle-shaped and oriented along the radial direction of the secondary particles.

[0014] In some embodiments, the diameter of the primary particle is 10 to 100 nm, and the aspect ratio of the primary particle is ≥ 3. The schematic diagram of the diameter and aspect ratio is as follows: Figure 1 As shown, D2 is the diameter, and the aspect ratio is the ratio of the longest diameter passing through the inside of the particle to the longest diameter perpendicular to it, that is, D1 / D2, which tends to be the average length and diameter value of needle-shaped or thin rod-shaped primary particles.

[0015] In some embodiments, the molar ratio of manganese, nickel, and cobalt in the doped lithium-rich manganese-based precursor is 0.55-0.80: 0.10-0.45: 0-0.20.

[0016] In some embodiments, the ratio of the molar amount of fluorine to the total molar amount of nickel, cobalt and manganese in the doped lithium-rich manganese-based precursor is 0.002-0.010:1, preferably 0.003-0.006:1; the ratio of the molar amount of phosphorus to the total molar amount of nickel, cobalt and manganese is 0.003-0.010:1, preferably 0.004-0.008:1.

[0017] In a second aspect, the present invention provides a method for preparing a doped lithium-rich manganese-based precursor, comprising the following steps:

[0018] A soluble nickel salt, a soluble manganese salt and an optional soluble cobalt salt are dissolved in water to form a metal salt solution, and soluble fluoride and phosphate are dissolved in an alkaline solution to form a precipitant solution. The reaction conditions are controlled, and the metal salt solution, the precipitant solution and the complexing agent are simultaneously added into a reactor to form a precipitate. The precipitate is filtered, washed and dried to obtain a F and P doped lithium-rich manganese-based precursor.

[0019] Preferably, the soluble nickel salt includes any one of nickel sulfate, nickel acetate, nickel chloride or nickel nitrate, or a combination of at least two of them; the soluble manganese salt includes any one of manganese sulfate, manganese acetate, manganese chloride or manganese nitrate, or a combination of at least two of them; and the soluble cobalt salt includes any one of cobalt sulfate, cobalt acetate, cobalt chloride or cobalt nitrate, or a combination of at least two of them.

[0020] Preferably, the concentration of the metal salt solution is 1-4 mol / L.

[0021] Preferably, the soluble fluoride includes one or more of NH4F, NaF, and KF; the soluble phosphate includes one or more of (NH4)3PO3, (NH4)2HPO3, NH4H2PO3, Na3PO3, Na2HPO3, NaH2PO3, K3PO3, K2HPO3, and KH2PO3.

[0022] Preferably, the concentration of the alkali solution is 1-4 mol / L.

[0023] Preferably, the complexing agent is aqueous ammonia with a concentration of 0.05-2 mol / L.

[0024] Preferably, the reaction conditions include: pH 10-12, temperature 40-60° C., and stirring speed 600-1000 r / min.

[0025] In a third aspect, the present invention provides a positive electrode material obtained by mixing the above-mentioned doped lithium-rich manganese-based precursor with a lithium source and then sintering the mixture.

[0026] Preferably, the lithium source includes any one of lithium acetate, lithium nitrate, lithium carbonate, and lithium hydroxide, or a combination of at least two thereof;

[0027] Preferably, the molar ratio of lithium to the total amount of metal (nickel, cobalt, manganese) in the lithium source is 1.1-1.6:1.

[0028] Preferably, the sintering conditions include: the sintering atmosphere is air or oxygen, first sintering at 400-600°C for 4-10h, and then sintering at 800-1000°C for 6-20h.

[0029] In a fourth aspect, the present invention provides a battery comprising the above-mentioned positive electrode material.

[0030] The battery is a lithium-ion battery.

[0031] Beneficial effects:

[0032] 1. The present invention obtains a F and P co-doped lithium-rich manganese-based precursor and material thereof. F and P are precipitated synchronously and can be evenly dispersed in the precursor to achieve uniform doping. The synergistic doping effect of F and P is utilized to effectively improve the electrochemical performance and cycle stability of the lithium-rich material;

[0033] 2. The present invention has obtained a technology for F and P to coordinately regulate the morphology and arrangement of primary particles of lithium-rich material precursors, and synthesize lithium-rich material precursors with radially oriented needle-shaped morphology, which is conducive to the rapid migration of lithium ions from the inside of the material to the surface, and effectively solves the stress problem of lithium-rich materials during the cycle process;

[0034] 3. The present invention provides a means of co-doping of F and P, in which doping elements are added simultaneously during the precursor synthesis process. The process is simple, the operation is convenient, the cost is low, and it has good economic benefits and is convenient for large-scale industrialization.

[0035] The present invention has been described in detail above, but the above embodiments are only illustrative in nature and are not intended to limit the present invention. In addition, this article is not limited by any theory described in the above prior art or invention content or the following examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the diameter and aspect ratio of primary particles;

[0037] Figure 2 This is the SEM image of the precursor of Example 1;

[0038] Figure 3 This is the EDS distribution diagram of the precursor of Example 1;

[0039] Figure 4 This is the SEM image of the precursor of Example 4;

[0040] Figure 5 This is the EDS distribution diagram of the precursor of Example 4;

[0041] Figure 6 This is the SEM image of the precursor of Comparative Example 1.

[0042] Figure 7 This is the SEM image of the precursor of Comparative Example 2.

[0043] Figure 8 This is the SEM image of the precursor of Comparative Example 3.

[0044] Fig. 9 This is the SEM image of the precursor of Comparative Example 4. DETAILED DESCRIPTION

[0045] The present invention is further described below in conjunction with examples. It should be noted that the following examples are provided for illustrative purposes only and do not constitute a limitation on the scope of protection claimed for the present invention.

[0046] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are conventional raw materials, reagents, methods in the art.

[0047] Example 1

[0048] (1) According to the molar ratio of Mn, Ni, and Co being 0.65:0.30:0.05, manganese sulfate, nickel sulfate, and cobalt sulfate were weighed and dissolved in deionized water to prepare a 2 mol / L mixed salt solution, a 4 mol / L NaOH solution containing 0.010 mol / L NH4F and 0.010 mol / L (NH4)2HPO3 was prepared as a precipitant, and ammonia water with a concentration of 1 mol / L was prepared as a complexing agent. The reaction solution was mixed for precipitation, the reaction temperature was controlled to be 50°C, the pH was 11, and the stirring speed was 800 rpm. After the reaction was completed, the filter was washed and dried to obtain Mn doped with 0.5% F and 0.5% P (molar percentage). 0.65 Ni 0.30 Co 0.05 (OH)2 precursor. Its SEM image is as follows Figure 2 As shown, it can be seen that the precursor is spherical, the primary particles are needle-shaped and arranged radially, the length of the primary particles is 100-250nm, the diameter is 15-45nm, and the aspect ratio is 4-10.

[0049] EDS distribution diagram Figure 3 As shown, it can be seen that the doping elements F and P are uniformly distributed in the precursor. From the EDS results, their molar percentages with the transition metal are 0.47% and 0.49%, respectively, which are basically consistent with the added amounts.

[0050] (2) The precursor and lithium carbonate (in terms of Li) were mixed at a molar ratio of the total amount of metal to Li of 1:1.4, and the mixture was heated at 500°C for 4 hours and then at 900°C for 12 hours in an air atmosphere, and then naturally cooled to room temperature to obtain a FP-doped lithium-rich manganese-based material.

[0051] Example 2

[0052] (1) According to the molar ratio of Mn, Ni, and Co being 0.55:0.25:0.2, manganese sulfate, nickel sulfate, and cobalt sulfate were weighed and dissolved in deionized water to prepare a 2 mol / L mixed salt solution, a 4 mol / L NaOH solution containing 0.006 mol / L NH4F and 0.014 mol / L (NH4)2HPO3 was prepared as a precipitant, and ammonia water with a concentration of 1 mol / L was prepared as a complexing agent. The reaction solution was mixed for precipitation, the reaction temperature was controlled to be 50°C, the pH was 10.5, and the stirring speed was 600 rpm. After the reaction was completed, the Mn doped with 0.3% F and 0.7% P was obtained. 0.55 Ni 0.25 Co 0.2 (OH)2 precursor.

[0053] (2) The precursor and lithium carbonate (in terms of Li) were mixed at a molar ratio of the total amount of metal to Li of 1:1.1, and the mixture was heated at 500°C for 4 hours and then at 800°C for 12 hours in an air atmosphere, and then naturally cooled to room temperature to obtain a FP-doped lithium-rich manganese-based material.

[0054] Example 3

[0055] (1) According to the molar ratio of Mn to Ni of 0.80:0.20, manganese sulfate and nickel sulfate were weighed and dissolved in deionized water to prepare a 2 mol / L mixed salt solution, a 4 mol / L NaOH solution containing 0.004 mol / L NH4F and 0.006 mol / L (NH4)2HPO3 was prepared as a precipitant, and ammonia water with a concentration of 1 mol / L was prepared as a complexing agent. The reaction solution was mixed for precipitation, and the reaction temperature was controlled to be 50°C, pH to be 10, and the stirring speed to be 900 rpm. After the reaction was completed, the Mn doped with 0.2% F and 0.3% P was obtained. 0.8 Ni 0.20 (OH)2 precursor.

[0056] (2) The precursor and lithium carbonate (in terms of Li) were mixed at a molar ratio of the total amount of metal to Li of 1:1.6, and the mixture was heated at 600°C for 4 hours in an air atmosphere, and then heated at 1000°C for 12 hours, and naturally cooled to room temperature to obtain a FP-doped lithium-rich manganese-based material.

[0057] Example 4

[0058] (1) According to the molar ratio of Mn, Ni, and Co being 0.6:0.30:0.1, manganese sulfate, nickel sulfate, and cobalt sulfate were weighed and dissolved in deionized water to prepare a 2 mol / L mixed salt solution, a 4 mol / L NaOH solution containing 0.008 mol / L NH4F and 0.012 mol / L (NH4)2HPO3 was prepared as a precipitant, and ammonia water with a concentration of 1 mol / L was prepared as a complexing agent. The reaction solution was mixed for precipitation, the reaction temperature was controlled to be 50°C, the pH was 11, and the stirring speed was 800 rpm. After the reaction was completed, the Mn doped with 0.4% F and 0.6% P was obtained. 0.6 Ni 0.30 Co 0.1 (OH)2 precursor. SEM Figure 4 As shown, it can be seen that the precursor is spherical, the primary particles are also needle-shaped and arranged radially, the length of the primary particles is 120-300nm, the diameter is 30-80nm, and the aspect ratio is 3.5-7.

[0059] EDS Figure 5 As shown, it can be seen that the doping elements F and P are uniformly distributed in the precursor. From the EDS results, their molar percentages with the transition metal are 0.38% and 0.57%, respectively, which are basically consistent with the added amounts.

[0060] (2) The precursor and lithium carbonate (in terms of Li) were mixed at a molar ratio of the total amount of metal to Li of 1:1.35, and the mixture was heated at 500°C for 4 hours and then at 800°C for 12 hours in an air atmosphere, and then naturally cooled to room temperature to obtain a FP-doped lithium-rich manganese-based material.

[0061] Example 5

[0062] (1) According to the molar ratio of Mn, Ni, and Co being 0.7:0.20:0.1, manganese sulfate, nickel sulfate, and cobalt sulfate were weighed and dissolved in deionized water to prepare a 2 mol / L mixed salt solution, a 4 mol / L NaOH solution containing 0.004 mol / L NH4F and 0.016 mol / L (NH4)2HPO3 was prepared as a precipitant, and ammonia water with a concentration of 1 mol / L was prepared as a complexing agent. The reaction solution was mixed for precipitation, and the reaction temperature was controlled to be 50°C, the pH was 12, and the stirring speed was 700 rpm. After the reaction was completed, the Mn doped with 0.2% F and 0.8% P was obtained. 0.7 Ni 0.20 Co 0.1 (OH)2 precursor.

[0063] (2) The precursor and lithium carbonate (in terms of Li) were mixed at a molar ratio of the total amount of metal to Li of 1:1.5, and the mixture was heated at 500°C for 4 hours in an air atmosphere, then heated at 950°C for 12 hours, and naturally cooled to room temperature to obtain a FP-doped lithium-rich manganese-based material.

[0064] Comparative Example 1

[0065] (1) According to the molar ratio of Mn, Ni, and Co being 0.65:0.30:0.05, manganese sulfate, nickel sulfate, and cobalt sulfate were weighed and dissolved in deionized water to prepare a 2 mol / L mixed salt solution, a 4 mol / L NaOH solution was prepared as a precipitant, and ammonia water with a concentration of 1 mol / L was prepared as a complexing agent. The reaction solution was mixed for precipitation, the reaction temperature was controlled to be 50°C, the pH was 11, and the stirring speed was 800 rpm. After the reaction was completed, the Mn was washed, filtered, and dried to obtain 0.65 Ni 0.30 Co 0.05 (OH)2 precursor. SEM Figure 6 As shown, it can be seen that the precursor is a loose spherical shape with multiple macropores composed of polygonal flake primary particles with different length and thickness distribution. The length of the primary particles ranges from 200 to 600 nm, and the thickness ranges from 30 to 150 nm.

[0066] (2) The precursor and lithium carbonate (in terms of Li) are mixed in a molar ratio of the total amount of metal to Li of 1:1.4, and the mixture is heated at 500°C for 4 hours in an air atmosphere, and then heated at 900°C for 12 hours, and then naturally cooled to room temperature to obtain a lithium-rich manganese-based material.

[0067] Comparative Example 2

[0068] (1) According to the molar ratio of Mn, Ni, and Co being 0.65:0.30:0.05, manganese sulfate, nickel sulfate, and cobalt sulfate were weighed and dissolved in deionized water to prepare a 2 mol / L mixed salt solution, a 4 mol / L NaOH solution containing 0.010 mol / L NH4F was prepared as a precipitant, and ammonia water with a concentration of 1 mol / L was prepared as a complexing agent. The reaction solution was mixed for precipitation, the reaction temperature was controlled to be 50°C, the pH was 11, and the stirring speed was 800 rpm. After the reaction was completed, the Mn doped with 0.5% F was obtained by washing, filtering, and drying. 0.65 Ni 0.30 Co 0.05 (OH)2 precursor. SEM image Figure 7 It can be seen that the precursor is similar to Comparative Example 1, which is a loose, porous, spherical shape, composed of polygonal flake primary particles with different length and thickness distributions. The length distribution of the primary particles is relatively wide, ranging from 200-1400nm, and the thickness ranges from 30-180nm.

[0069] (2) The precursor and lithium carbonate (in terms of Li) were mixed at a molar ratio of the total amount of metal to Li of 1:1.4, and the mixture was heated at 500°C for 4 hours in an air atmosphere, then heated at 900°C for 12 hours, and naturally cooled to room temperature to obtain a F-doped lithium-rich manganese-based material.

[0070] Comparative Example 3

[0071] (1) According to the molar ratio of Mn, Ni, and Co being 0.65:0.30:0.05, manganese sulfate, nickel sulfate, and cobalt sulfate were weighed and dissolved in deionized water to prepare a 2 mol / L mixed salt solution, a 4 mol / L NaOH solution containing 0.010 mol / L (NH4)2HPO3 was prepared as a precipitant, and ammonia water with a concentration of 1 mol / L was prepared as a complexing agent. The reaction solution was mixed for precipitation, the reaction temperature was controlled to be 50°C, the pH was 11, and the stirring speed was 800 rpm. After the reaction was completed, the Mn doped with 0.5% P was obtained by washing, filtering, and drying. 0.65 Ni 0.30 Co 0.05 (OH)2 precursor. SEM image Figure 8 It can be seen that the precursor is also similar to Comparative Example 1, which is a spherical shape composed of flaky or blocky polygonal primary particles. The length and thickness distribution ranges of the primary particles are relatively wide, with a length range of 400-1500nm and a thickness range of 50-450nm.

[0072] (2) The precursor and lithium carbonate (in terms of Li) were mixed at a molar ratio of the total amount of metal to Li of 1:1.4, and the mixture was heated at 500° C. for 4 hours in an air atmosphere, and then heated at 900° C. for 12 hours, and naturally cooled to room temperature to obtain a P-doped lithium-rich manganese-based material.

[0073] Comparative Example 4

[0074] (1) According to the molar ratio of Mn, Ni, and Co being 0.65:0.30:0.05, manganese sulfate, nickel sulfate, and cobalt sulfate were weighed and dissolved in deionized water to prepare a 2 mol / L mixed salt solution, a 4 mol / L NaOH solution containing 0.010 mol / L Na2FPO3 was prepared as a precipitant, and ammonia water with a concentration of 1 mol / L was prepared as a complexing agent. The reaction solution was mixed for precipitation, the reaction temperature was controlled to be 50°C, the pH was 11, and the stirring speed was 800 rpm. After the reaction was completed, the Mn doped with 0.5% F and 0.5% P was obtained. 0.65 Ni 0.30 Co 0.05 (OH)2 precursor. SEM image Fig. 9 , it can be seen that the secondary particles of the precursor are also spherical, and the primary particles are non-radially arranged, similar to a loose fibrous morphology.

[0075] (2) The precursor and lithium carbonate (in terms of Li) were mixed at a molar ratio of the total amount of metal to Li of 1:1.4, and the mixture was heated at 500°C for 4 hours in an air atmosphere, then heated at 900°C for 12 hours, and naturally cooled to room temperature to obtain a F- and P-doped lithium-rich manganese-based material.

[0076] The positive electrode active materials of the above-mentioned embodiments and comparative examples, acetylene black, polyvinylidene fluoride and N-methylpyrrolidone were mixed to form a slurry, which was evenly coated on the surface of an aluminum foil to obtain a positive electrode plate; then, a lithium plate was used as a negative electrode plate, and a 1 mol / L lithium hexafluorophosphate ethylene carbonate (EC) and dimethyl carbonate (DMC) solution (the volume ratio of EC to DMC was 1:1) was used as an electrolyte, and the mixture was assembled in a glove box to obtain a lithium-ion battery.

[0077] The lithium-ion battery was tested for cycle performance using an electrochemical tester at a temperature of 25°C and current densities of 0.1C, 1C, and 3C (1C = 200 mAg -1 ), the charge and discharge voltage range is 4.6~2.0V, and the battery's initial charge and discharge performance, 1C and 3C rate performance are tested. The cycle performance is tested at 2.0-4.4V, 1C / 1C.

[0078] The results are shown in Table 1.

[0079] Table 1. Test results of buckling performance

[0080]

[0081]

[0082] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents, without departing from the spirit and essence of the claims of the present invention; and these modifications or replacements are still within the scope defined by the claims of the present invention.

Claims

1. A doped lithium-rich manganese-based precursor, characterized in that: The doped lithium-rich manganese-based precursor is nickel manganese hydroxide or nickel cobalt manganese hydroxide doped with fluorine and phosphorus elements; The doped lithium-rich manganese-based precursor is a secondary spherical or quasi-spherical particle composed of primary particles. The primary particles are needle-shaped and oriented along the radial direction of the secondary particles.

2. The doped lithium-rich manganese-based precursor according to claim 1, characterized in that: The diameter of the primary particles is 10 to 100 nm, and the aspect ratio of the primary particles is ≥3.

3. The doped lithium-rich manganese-based precursor according to claim 1, characterized in that: The molar ratio of manganese, nickel and cobalt in the doped lithium-rich manganese-based precursor is 0.55-0.80: 0.10-0.45: 0-0.

20.

4. The doped lithium-rich manganese-based precursor according to claim 1, characterized in that: The ratio of the molar amount of fluorine to the total molar amount of nickel, cobalt and manganese in the doped lithium-rich manganese-based precursor is 0.002-0.010:1; the ratio of the molar amount of phosphorus to the total molar amount of nickel, cobalt and manganese is 0.003-0.010:

1.

5. A method for preparing a doped lithium-rich manganese-based precursor according to any one of claims 1 to 4, characterized in that: The following steps are involved: A soluble nickel salt, a soluble manganese salt and an optional soluble cobalt salt are dissolved in water to form a metal salt solution, and soluble fluoride and phosphate are dissolved in an alkaline solution to form a precipitant solution. The reaction conditions are controlled, and the metal salt solution, the precipitant solution and the complexing agent are simultaneously added into a reactor to form a precipitate. The precipitate is filtered, washed and dried to obtain a F and P doped lithium-rich manganese-based precursor.

6. The preparation method according to claim 5, characterized in that: The soluble nickel salt includes any one of nickel sulfate, nickel acetate, nickel chloride or nickel nitrate or a combination of at least two thereof; the soluble manganese salt includes any one of manganese sulfate, manganese acetate, manganese chloride or manganese nitrate or a combination of at least two thereof; the soluble cobalt salt includes any one of cobalt sulfate, cobalt acetate, cobalt chloride or cobalt nitrate or a combination of at least two thereof; Soluble fluorides include one or more of NH4F, NaF, and KF; soluble phosphates include one or more of (NH4)3PO3, (NH4)2HPO3, NH4H2PO3, Na3PO3, Na2HPO3, NaH2PO3, K3PO3, K2HPO3, and KH2PO3.

7. The preparation method according to claim 5, characterized in that: The concentration of the metal salt solution is 1-4 mol / L; The concentration of alkali solution is 1-4 mol / L; The complexing agent is ammonia water with a concentration of 0.05-2 mol / L.

8. The preparation method according to claim 5, characterized in that: The reaction conditions include: pH 10-12, temperature 40-60° C., and stirring speed 600-1000 r / min.

9. A positive electrode material, characterized in that: The doped lithium-rich manganese-based precursor according to any one of claims 1 to 4 is mixed with a lithium source and then sintered.

10. A battery, characterized in that: Comprising the positive electrode material according to claim 9.

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