Lithium-rich manganese-based material for solid-state battery as well as preparation method and application of lithium-rich manganese-based material

Abstract

The invention provides a lithium-rich manganese-based material for a solid-state battery and a preparation method and application of the lithium-rich manganese-based material, and the preparation method comprises the following steps: carrying out coprecipitation reaction on a nickel-manganese mixed metal source solution, a first complexing agent solution, a second complexing agent solution, a third complexing agent solution and a precipitator solution to obtain precursor particles; the types of complexing agents in the first complexing agent solution, the second complexing agent solution and the third complexing agent solution are different, and the third complexing agent solution comprises a porphyrin complexing agent; and mixing and sintering a lithium source and the precursor particles to obtain the lithium-rich manganese-based material for the solid-state battery. According to the preparation method disclosed by the invention, the high-dispersity small-particle manganese-rich precursor can be prepared by adopting a method of matching multiple complexing agents, so that the high-dispersity small-particle lithium-rich manganese-based material can be prepared, the lithium-rich manganese-based material can be ensured to be in better contact with a solid electrolyte, and the performance of the solid-state battery is improved.

Description

Technical Field

[0001] The battery of the present invention belongs to the technical field of batteries and relates to a lithium-rich manganese-based material for solid-state batteries and a preparation method and application thereof. Background Art

[0002] With the continuous development of lithium-ion battery technology, solid-state batteries have become one of the hot topics of research. Due to its advantages such as high energy density, long life and low cost, it has broad application prospects in electric vehicles, mobile devices and other fields. However, due to the poor conductivity of solid electrolytes, conventional large-particle positive electrode materials are difficult to use in solid-state batteries. Therefore, single-crystal small-particle positive electrode materials are generally used to improve conductivity. Lithium-rich manganese-based positive electrode materials have become a hot spot for the research and development and application of solid-state battery positive electrodes due to their ultra-high specific capacity.

[0003] Although the current nano-scale lithium-rich manganese-based cathode materials have a high capacity, their cycle performance is extremely poor. The current ternary precursor co-precipitation method cannot prepare highly dispersed small-particle manganese-rich precursors.

[0004] Based on the above research, it is necessary to provide a method for preparing a lithium-rich manganese-based positive electrode material for a solid-state battery. The preparation method can not only prepare an ultra-small particle manganese-rich precursor, but also obtain a highly dispersed small particle lithium-rich manganese-based positive electrode material, so as to better adapt to the application of solid-state batteries. Summary of the invention

[0005] The object of the present invention is to provide a lithium-rich manganese-based material for solid-state batteries, and a preparation method and application thereof. The preparation method can prepare a highly dispersible small-particle manganese-rich precursor by using a combination of multiple complexing agents, thereby preparing a highly dispersible small-particle lithium-rich manganese-based material to ensure that the lithium-rich manganese-based material is in better contact with the solid electrolyte, thereby improving the performance of the solid-state battery.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a lithium-rich manganese-based material for a solid-state battery, the preparation method comprising the following steps:

[0008] (1) subjecting a nickel-manganese mixed metal source solution, a first complexing agent solution, a second complexing agent solution, a third complexing agent solution and a precipitant solution to a coprecipitation reaction to obtain precursor particles;

[0009] The first complexing agent solution, the second complexing agent solution and the third complexing agent solution include different types of complexing agents, and the third complexing agent solution includes a porphyrin complexing agent;

[0010] (2) Mixing and sintering the lithium source and the precursor particles in step (1) to obtain the lithium-rich manganese-based material for the solid-state battery.

[0011] The present invention can prepare precursor particles with smaller particles by using three complexing agents in combination when preparing precursor particles. Among them, the porphyrin complexing agent is used to match the lithium-manganese-rich precursor material. The porphyrin complexing agent has a stronger complexing ability for manganese ions, which is conducive to the preparation of smaller precursor particles. Therefore, the present invention can prepare highly dispersible small-particle lithium-rich manganese-based materials to ensure that the lithium-rich manganese-based materials are in better contact with the solid electrolyte, thereby improving the performance of the solid-state battery.

[0012] Preferably, the porphyrin complexing agent in step (1) comprises a water-soluble porphyrin compound.

[0013] Preferably, the water-soluble porphyrin compound includes any one of meso-tetrakis(4-carboxyphenyl)porphyrin, meso-tetrakis(4-sulfonatephenyl)porphyrin or meso-tetrakis(4-trimethylammoniumphenyl)porphyrin, or a combination of at least two thereof.

[0014] Preferably, the first complexing agent solution in step (1) comprises aqueous ammonia.

[0015] Preferably, the second complexing agent solution in step (1) comprises citric acid.

[0016] Preferably, the pH of the coprecipitation reaction in step (1) is 9-13, for example, 9, 10, 11, 12 or 13, and the temperature is 40-60°C, for example, 40°C, 50°C or 60°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, the nickel-cobalt-manganese mixed metal source solution, the first complexing agent solution, the second complexing agent solution, the third complexing agent solution and the precipitant solution in step (1) are introduced into the base solution to carry out a coprecipitation reaction.

[0018] Preferably, the coprecipitation reaction includes a nucleation reaction stage and a growth reaction stage, wherein the introduction of the third complexing agent solution is stopped during the growth reaction stage.

[0019] The present invention preferably introduces the third complexing agent solution only during the nucleation reaction stage, which can achieve a gradient distribution of manganese ions, increase the manganese ion content in the core, and reduce the dissolution of manganese ions.

[0020] Preferably, the pH of the nucleation reaction stage is 11.1-13, for example, 11.1, 12 or 13, and the pH of the growth reaction stage is 9-11, for example, 9, 10 or 11, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, the nucleation reaction time is 15-25h, for example, 15h, 20h or 25h, and the growth reaction phase time is 80-100h, for example, 80h, 90h or 100h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, in the nucleation reaction stage, the concentration of the third complexing agent solution is 0.1-0.4 g / L, for example, 0.1 g / L, 0.2 g / L, 0.3 g / L or 0.4 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0023] Preferably, in the nucleation reaction stage, the concentration of the first complexing agent solution is 0.2-0.8 g / L, for example, 0.2 g / L, 0.4 g / L, 0.6 g / L or 0.8 g / L, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, in the nucleation reaction stage, the concentration of the second complexing agent solution is 2-6 g / L, for example, 2 g / L, 4 g / L or 0.6 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0025] Preferably, the base solution comprises water, a precipitant solution and a first complexing agent solution.

[0026] Preferably, the pH of the base solution is 9-12, for example, 9, 10, 11 or 12, the ammonia concentration is 0.1-10 g / L, for example, 0.1 g / L, 0.5 g / L, 1 g / L, 2 g / L, 5 g / L or 10 g / L, and the temperature is 40-60°C, for example, 40°C, 50°C or 60°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0027] Preferably, the concentration of the first complexing agent solution in step (1) is 1-10 mol / L, for example, 1 mol / L, 3 mol / L, 5 mol / L, 8 mol / L or 10 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] Preferably, the concentration of the second complexing agent solution in step (1) is 20-40 g / L, for example, 20 g / L, 30 g / L or 40 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] Preferably, the concentration of the third complexing agent solution in step (1) is 30-50 g / L, for example, 30 g / L, 40 g / L or 50 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] Preferably, the concentration of the nickel-manganese mixed metal source solution in step (1) is 1.6-2.4 mol / L, for example, 1.6 mol / L, 2 mol / L or 2.4 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] Preferably, the concentration of the precipitant solution in step (1) is 9-12 mol / L, for example, 9 mol / L, 10 mol / L, 11 mol / L or 12 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0032] Preferably, the precipitant solution in step (1) comprises liquid alkali.

[0033] Preferably, the coprecipitation reaction in step (1) is carried out in an oxygen-containing gas, wherein the oxygen-containing gas comprises a mixture of oxygen and nitrogen in a volume ratio of (0-5):10, but excluding 0:10, for example, 1:10, 2:10, 4:10 or 5:10, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0034] Preferably, after the coprecipitation reaction in step (1) is completed, aging, solid-liquid separation, washing and drying are further performed.

[0035] Preferably, the particle size D50 of the precursor particles in step (1) is 1-3.5 μm, for example, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm or 3.5 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the sintering in step (2) includes first sintering at 300-500°C, such as 300°C, 400°C or 500°C, for 3-5 hours, such as 3 hours, 4 hours or 5 hours, and then sintering at 700-900°C, such as 700°C, 800°C or 900°C, for 7-9 hours, such as 7 hours, 8 hours or 9 hours, but is not limited to the listed values, and other values ​​within the numerical range not listed are also applicable.

[0037] As a preferred technical solution of the preparation method of the present invention, the preparation method comprises the following steps:

[0038] (1) In an oxygen-containing gas, a nickel-manganese mixed metal source solution, a first complexing agent solution, a second complexing agent solution, a third complexing agent solution and a precipitant solution are introduced into a base solution, a nucleation reaction is carried out at a pH of 11.1-13 for 15-25 hours, and then the introduction of the third complexing agent solution is stopped, and a growth reaction is carried out at a pH of 9-11 for 80-100 hours, and then aging, solid-liquid separation, washing and drying are carried out to obtain precursor particles with a particle size D50 of 1-3.5 μm;

[0039] The first complexing agent solution includes ammonia water, the second complexing agent solution includes citric acid, and the third complexing agent solution includes a porphyrin complexing agent;

[0040] (2) Mixing the lithium source and the precursor particles of step (1), and then keeping the mixture at 300-500° C. for 3-5 hours, and then keeping the mixture at 700-900° C. for 7-9 hours, to obtain the lithium-rich manganese-based material for the solid-state battery.

[0041] In a second aspect, the present invention provides a lithium-rich manganese-based material for a solid-state battery, wherein the lithium-rich manganese-based material for a solid-state battery is prepared by the preparation method described in the first aspect.

[0042] In a third aspect, the present invention provides a solid-state battery, comprising the lithium-rich manganese-based material for a solid-state battery as described in the second aspect.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present invention can prepare precursor particles with smaller particles by using three complexing agents in combination when preparing precursor particles. Among them, the porphyrin complexing agent is used to match the lithium-manganese-rich precursor material. The porphyrin complexing agent has a stronger complexing ability for manganese ions, which is conducive to the preparation of smaller precursor particles. Therefore, the present invention can prepare highly dispersible small-particle lithium-rich manganese-based materials to ensure that the lithium-rich manganese-based materials are in better contact with the solid electrolyte, thereby improving the performance of the solid-state battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a SEM image of the precursor particles described in Example 1 of the present invention. DETAILED DESCRIPTION

[0046] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0047] Example 1

[0048] This embodiment provides a method for preparing a lithium-rich manganese-based material for a solid-state battery, the preparation method comprising the following steps:

[0049] (1) A nickel-manganese mixed metal source solution with a total ion concentration of 2 mol / L is prepared by using manganese sulfate and nickel sulfate, wherein the molar ratio of nickel ions to manganese ions is 25:75, and then the nickel-manganese mixed metal source solution, ammonia water with a concentration of 1 mol / L, a citric acid aqueous solution with a concentration of 30 g / L, a meso-tetrakis(4-carboxyphenyl)porphyrin aqueous solution with a concentration of 40 g / L and a liquid alkali solution with a concentration of 10 mol / L are introduced into a base liquid (the pH of the base liquid is 12, the ammonia concentration is 0.5 g / L, the citric acid concentration is 3 g / L, and the meso-tetrakis(4-carboxyphenyl)porphyrin concentration is 0.3 g / L) at a volume ratio of 3:1. In a mixed atmosphere of oxygen and nitrogen, a nucleation coprecipitation reaction was carried out at a temperature of 50°C, a rotation speed of 500 rpm and a pH of 11.3 for 20 hours, during which the concentration of ammonia water in the system was controlled to be 0.5 g / L, the concentration of citric acid aqueous solution was 3 g / L, the concentration of meso-tetra(4-carboxyphenyl)porphyrin was 0.3 g / L, and the temperature was 50°C. Then, the introduction of meso-tetra(4-carboxyphenyl)porphyrin aqueous solution was stopped, and a growth reaction was carried out at a pH of 9.5 for 90 hours. After the coprecipitation reaction was completed, the particles were aged, centrifuged, washed, dried, and magnetic foreign matter was removed to obtain precursor particles with a particle size D50 of 1.5 μm. The SEM image of the precursor particles is shown in FIG. Figure 1 As shown;

[0050] (2) Mixing lithium hydroxide and the precursor particles of step (1), and then keeping the mixture at 400° C. for 4 hours and then keeping the mixture at 800° C. for 8 hours to obtain the lithium-rich manganese-based material for the solid-state battery.

[0051] Example 2

[0052] This embodiment provides a method for preparing a lithium-rich manganese-based material for a solid-state battery, the preparation method comprising the following steps:

[0053] (1) A nickel-manganese mixed metal source solution with a total ion concentration of 1.6 mol / L is prepared using manganese sulfate and nickel sulfate, wherein the molar ratio of nickel ions to manganese ions is 25:75, and then the nickel-manganese mixed metal source solution, ammonia water with a concentration of 5 mol / L, a citric acid aqueous solution with a concentration of 20 g / L, a meso-tetrakis(4-carboxyphenyl)porphyrin aqueous solution with a concentration of 30 g / L, and a liquid alkali solution with a concentration of 9 mol / L are introduced into a base solution (the pH of the base solution is 11.5, the ammonia concentration is 0.8 g / L, the citric acid concentration is 3 g / L, and the meso-tetrakis(4-carboxyphenyl)porphyrin is 9 mol / L). The method comprises the following steps: a) performing a nucleation reaction at a temperature of 60°C and a pH of 13 for 15 hours in a mixed atmosphere of oxygen and nitrogen with a volume ratio of 2:10, during which the concentration of ammonia in the system is controlled to be 0.8 g / L, the concentration of citric acid aqueous solution is controlled to be 2 g / L, and the concentration of meso-tetra(4-carboxyphenyl)porphyrin is controlled to be 0.1 g / L, and then stopping the introduction of meso-tetra(4-carboxyphenyl)porphyrin aqueous solution, and performing a growth reaction at a pH of 11 for 80 hours. After the coprecipitation reaction is completed, the system is aged, centrifuged, washed, dried, and magnetic foreign matter is removed to obtain precursor particles with a particle size D50 of 1 μm.

[0054] (2) Mixing the lithium source and the precursor particles of step (1), and then keeping the mixture at 500° C. for 3 h, and then keeping the mixture at 900° C. for 7 h, to obtain the lithium-rich manganese-based material for the solid-state battery.

[0055] Example 3

[0056] This embodiment provides a method for preparing a lithium-rich manganese-based material for a solid-state battery, the preparation method comprising the following steps:

[0057] (1) A nickel-manganese mixed metal source solution with a total ion concentration of 2.4 mol / L is prepared by using manganese sulfate and nickel sulfate, wherein the molar ratio of nickel ions to manganese ions is 25:75, and then the nickel-manganese mixed metal source solution, 8 mol / L ammonia water, 40 g / L citric acid aqueous solution, 50 g / L meso-tetrakis(4-carboxyphenyl)porphyrin aqueous solution and 12 mol / L liquid alkali solution are introduced into a base solution (the pH of the base solution is 11, the ammonia concentration is 1.0 g / L, the citric acid concentration is 4 g / L, the meso-tetrakis(4-carboxyphenyl)porphyrin The method comprises the following steps: in a mixture of oxygen and nitrogen with a volume ratio of 5:10, a nucleation reaction is carried out at a temperature of 40°C and a pH of 13 for 25 hours, during which the concentration of ammonia water in the system is controlled to be 0.2 g / L, the concentration of citric acid aqueous solution is controlled to be 6 g / L, and the concentration of meso-tetrakis(4-carboxyphenyl)porphyrin is controlled to be 0.4 g / L, and then the introduction of meso-tetrakis(4-carboxyphenyl)porphyrin aqueous solution is stopped, and a growth reaction is carried out at a pH of 9 for 100 hours. After the coprecipitation reaction is completed, the particles are aged, centrifuged, washed, dried, and magnetic foreign matter is removed to obtain precursor particles with a particle size D50 of 2 μm.

[0058] (2) Mixing the lithium source and the precursor particles of step (1), and then keeping the mixture at 300° C. for 5 hours and then at 700° C. for 9 hours to obtain the lithium-rich manganese-based material for the solid-state battery.

[0059] Example 4

[0060] This embodiment provides a method for preparing a lithium-rich manganese-based material for a solid-state battery. The preparation method is the same as that of Example 1, except that during the nucleation reaction, the concentration of the meso-tetrakis(4-carboxyphenyl)porphyrin aqueous solution in the system is 0.05 g / L.

[0061] Example 5

[0062] This embodiment provides a method for preparing a lithium-rich manganese-based material for a solid-state battery. The preparation method is the same as that of Example 1, except that during the nucleation reaction, the concentration of the meso-tetrakis(4-carboxyphenyl)porphyrin aqueous solution in the system is 0.6 g / L.

[0063] Example 6

[0064] This embodiment provides a method for preparing a lithium-rich manganese-based material for a solid-state battery. The preparation method is the same as that of Example 1, except that the introduction of the meso-tetrakis(4-carboxyphenyl)porphyrin aqueous solution is not stopped during the growth reaction.

[0065] Comparative Example 1

[0066] This comparative example provides a method for preparing a lithium-rich manganese-based material for a solid-state battery. The preparation method is the same as Example 1 except that the meso-tetrakis(4-carboxyphenyl)porphyrin aqueous solution is not introduced during the coprecipitation.

[0067] Comparative Example 2

[0068] This comparative example provides a method for preparing a lithium-rich manganese-based material for a solid-state battery. The preparation method is the same as Example 1 except that only ammonia water is used as a complexing agent in the nucleation reaction and the growth reaction of the co-precipitation.

[0069] Comparative Example 3

[0070] This comparative example provides a method for preparing a lithium-rich manganese-based material for a solid-state battery. The preparation method is the same as Example 1 except that only citric acid solution is used as a complexing agent in both the nucleation reaction and the growth reaction of the co-precipitation.

[0071] Comparative Example 4

[0072] This comparative example provides a method for preparing a lithium-rich manganese-based material for a solid-state battery. The preparation method is the same as Example 1, except that only meso-tetrakis(4-carboxyphenyl)porphyrin aqueous solution is used as a complexing agent in both the nucleation reaction and the growth reaction of the coprecipitation.

[0073] The lithium-rich manganese-based material for solid-state batteries obtained in the above embodiments and comparative examples is mixed with lithium-rich manganese-based material for solid-state batteries, acetylene black and polyvinylidene fluoride in a mass ratio of 8:1:1, and then N-methyl-2-pyridine is dropped into the solution to prepare the solution, which is evenly applied on an aluminum foil, dried and stamped into battery pole pieces, and the battery pole pieces, single lithium sheets, glass fiber diaphragms, solid electrolyte sheets, shrapnel and battery shells are assembled into button batteries in an Ar gas glove box.

[0074] The obtained battery was tested for its capacity and cycle performance. The test conditions were: after activation for 3 cycles at a voltage of 2.0-4.8V and a rate of 0.1C, it was cycled for 100 cycles at 1C to obtain its cycle specific capacity and capacity retention rate. The test results are shown in Table 1:

[0075] Table 1

[0076] Initial specific capacity (mAh / g) Capacity retention after 100 cycles (%) Example 1 288.3 87.0 Example 2 283.7 87.2 Example 3 282.4 86.5 Example 4 273.8 85.5 Example 5 267.6 86.7 Example 6 262.9 88.4 Comparative Example 1 274.2 67.5 Comparative Example 2 262.4 72.5 Comparative Example 3 267.1 68.5 Comparative Example 4 259.4 71.2

[0077] From Table 1 we can see that:

[0078] The present invention adopts three complexing agents for co-precipitation, and can prepare a highly dispersible small-particle manganese-rich precursor, thereby improving the performance of lithium-rich manganese-based materials; it can be seen from Example 1 and Comparative Examples 1-4 that if no porphyrin complexing agent is added, or only one complexing agent is used for co-precipitation reaction, the co-precipitation reaction effect is reduced, and the performance of the obtained lithium-rich manganese-based material is reduced; it can be seen from Example 1 and Examples 4-5 that during the nucleation reaction, the concentration of the porphyrin complexing agent in the system will affect its complexing effect, thereby affecting the distribution of manganese ions and affecting the performance of the material finally obtained; it can be seen from Example 1 and Example 6 that the present invention preferably introduces the porphyrin complexing agent only in the nucleation stage, so as to optimize the distribution of manganese ions, reduce the dissolution of manganese ions, and thus improve the performance of the material.

[0079] In summary, the present invention provides a lithium-rich manganese-based material for solid-state batteries, and a preparation method and application thereof. The preparation method can prepare a highly dispersible small-particle manganese-rich precursor by using a combination of multiple chelating agents, thereby preparing a highly dispersible small-particle lithium-rich manganese-based material, to ensure that the lithium-rich manganese-based material is in better contact with the solid electrolyte, thereby improving the performance of the solid-state battery.

[0080] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a lithium-rich manganese-based material for a solid-state battery, characterized in that: The preparation method comprises the following steps: (1) subjecting a nickel-manganese mixed metal source solution, a first complexing agent solution, a second complexing agent solution, a third complexing agent solution and a precipitant solution to a coprecipitation reaction to obtain precursor particles; The first complexing agent solution, the second complexing agent solution and the third complexing agent solution include different types of complexing agents, and the third complexing agent solution includes a porphyrin complexing agent; (2) Mixing and sintering the lithium source and the precursor particles in step (1) to obtain the lithium-rich manganese-based material for the solid-state battery.

2. The preparation method according to claim 1, characterized in that: The porphyrin complexing agent in step (1) comprises a water-soluble porphyrin compound; Preferably, the water-soluble porphyrin compound includes any one or a combination of at least two of meso-tetrakis(4-carboxyphenyl)porphyrin, meso-tetrakis(4-sulfonatephenyl)porphyrin or meso-tetrakis(4-trimethylammoniumphenyl)porphyrin; Preferably, the first complexing agent solution in step (1) comprises aqueous ammonia; Preferably, the second complexing agent solution in step (1) comprises citric acid; Preferably, the pH of the coprecipitation reaction in step (1) is 9-13 and the temperature is 40-60°C.

3. The preparation method according to claim 1 or 2, characterized in that: Passing the nickel-cobalt-manganese mixed metal source solution, the first complexing agent solution, the second complexing agent solution, the third complexing agent solution and the precipitant solution described in step (1) into the base solution to carry out a coprecipitation reaction; Preferably, the coprecipitation reaction includes a nucleation reaction stage and a growth reaction stage, wherein the introduction of the third complexing agent solution is stopped during the growth reaction stage.

4. The preparation method according to claim 3, characterized in that: The pH value of the nucleation reaction stage is 11.1-13, and the pH value of the growth reaction stage is 9-11; Preferably, the nucleation reaction time is 15-25 hours, and the growth reaction time is 80-100 hours; Preferably, in the nucleation reaction stage, the concentration of the third complexing agent solution is 0.1-0.4 g / L; Preferably, in the nucleation reaction stage, the concentration of the first complexing agent solution is 0.2-0.8 g / L; Preferably, in the nucleation reaction stage, the concentration of the second complexing agent solution is 2-6 g / L; Preferably, the base solution comprises water, a precipitant solution and a first complexing agent solution; Preferably, the pH of the base solution is 9-12, the ammonia concentration is 0.1-10 g / L, and the temperature is 40-60°C.

5. The preparation method according to any one of claims 1 to 4, characterized in that: Step (1) The concentration of the first complexing agent solution is 1-10 mol / L; Preferably, the concentration of the second complexing agent solution in step (1) is 20-40 g / L; Preferably, the concentration of the third complexing agent solution in step (1) is 30-50 g / L; Preferably, the concentration of the nickel-manganese mixed metal source solution in step (1) is 1.6-2.4 mol / L; Preferably, the concentration of the precipitant solution in step (1) is 9-12 mol / L.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The coprecipitation reaction in step (1) is carried out in an oxygen-containing gas; Preferably, after the coprecipitation reaction in step (1) is completed, aging, solid-liquid separation, washing and drying are further performed.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The particle size D50 of the precursor particles in step (1) is 1-3.5 μm; Preferably, the sintering in step (2) includes first keeping the temperature at 300-500° C. for 3-5 hours, and then keeping the temperature at 700-900° C. for 7-9 hours.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: (1) In an oxygen-containing gas, a nickel-manganese mixed metal source solution, a first complexing agent solution, a second complexing agent solution, a third complexing agent solution and a precipitant solution are introduced into a base solution, a nucleation reaction is carried out at a pH of 11.1-13 for 15-25 hours, and then the introduction of the third complexing agent solution is stopped, and a growth reaction is carried out at a pH of 9-11 for 80-100 hours, and then aging, solid-liquid separation, washing and drying are carried out to obtain precursor particles with a particle size D50 of 1-3.5 μm; The first complexing agent solution includes ammonia water, the second complexing agent solution includes citric acid, and the third complexing agent solution includes a porphyrin complexing agent; (2) Mixing the lithium source and the precursor particles of step (1), and then keeping the mixture at 300-500° C. for 3-5 hours, and then keeping the mixture at 700-900° C. for 7-9 hours, to obtain the lithium-rich manganese-based material for the solid-state battery.

9. A lithium-rich manganese-based material for solid-state batteries, characterized in that: The lithium-rich manganese-based material for solid-state batteries is prepared by the preparation method according to any one of claims 1 to 8.

10. A solid-state battery, characterized in that: The solid-state battery comprises the lithium-rich manganese-based material for a solid-state battery as claimed in claim 9.

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