A lithium-rich manganese-based material for solid-state batteries, its preparation method and application

Abstract

This invention provides a lithium-rich manganese-based material for solid-state batteries, its preparation method, and its application. The preparation method includes the following steps: co-precipitating 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 obtain precursor particles; the first, second, and third complexing agent solutions contain different types of complexing agents, and the third complexing agent solution includes a porphyrin-based complexing agent; mixing and sintering a lithium source and the precursor particles to obtain the lithium-rich manganese-based material for solid-state batteries. The preparation method of this invention, by using a combination of multiple complexing agents, can prepare highly dispersed small-particle manganese-rich precursors, thereby enabling the preparation of highly dispersed small-particle lithium-rich manganese-based materials. This ensures better contact between the lithium-rich manganese-based material and the solid electrolyte, thus improving the performance of solid-state batteries.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a lithium-rich manganese-based material for solid-state batteries, its preparation method, and its application. Background Technology

[0002] With the continuous development of lithium-ion battery technology, solid-state batteries have become a research hotspot. Due to their advantages such as high energy density, long lifespan, and low cost, they have broad application prospects in electric vehicles, mobile devices, and other fields. However, because solid electrolytes have poor conductivity, conventional large-particle cathode materials are difficult to use in solid-state batteries. Therefore, single-crystal small-particle cathode materials are commonly used to improve conductivity. Lithium-rich manganese-based cathode materials, due to their ultra-high specific capacity, have become a current research and application hotspot for solid-state battery cathodes.

[0003] While current nanoscale lithium-rich manganese-based cathode materials possess high capacity, their cycle performance is extremely poor. Furthermore, current ternary precursor co-precipitation methods cannot produce highly dispersed small-particle manganese-rich precursors.

[0004] Based on the above research, there is a need to provide a method for preparing lithium-rich manganese-based cathode materials for solid-state batteries. This method can not only prepare ultra-small particle manganese-rich precursors, but also obtain highly dispersed small particle lithium-rich manganese-based cathode materials, thus better adapting them to the application of solid-state batteries. Summary of the Invention

[0005] The purpose of this invention is to provide a lithium-rich manganese-based material for solid-state batteries, its preparation method, and its application. The preparation method uses a combination of various complexing agents to prepare a highly dispersed small-particle manganese-rich precursor, thereby enabling the preparation of a highly dispersed small-particle lithium-rich manganese-based material. This ensures better contact between the lithium-rich manganese-based material and the solid electrolyte, thereby improving the performance of the solid-state battery.

[0006] To achieve this objective, the present invention adopts the following technical solution:

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

[0008] (1) 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 were subjected to a co-precipitation reaction to obtain precursor particles;

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

[0010] (2) The lithium source and the precursor particles described in step (1) are mixed and sintered to obtain the lithium-rich manganese-based material for solid-state batteries.

[0011] This invention utilizes a combination of three complexing agents during the preparation of precursor particles, enabling the production of smaller precursor particles. The porphyrin-based complexing agent is used to complement the lithium-rich manganese precursor material. Porphyrin-based complexing agents have a stronger ability to complex manganese ions, thus facilitating the preparation of smaller precursor particles. Therefore, this invention can produce highly dispersed small-particle lithium-rich manganese-based materials, ensuring better contact between the lithium-rich manganese-based material and the solid-state electrolyte, thereby improving the performance of solid-state batteries.

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

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

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

[0015] Preferably, in step (1), the second complexing agent solution includes 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℃, for example, 40℃, 50℃ or 60℃, but not limited to the listed values. Other unlisted values ​​within the 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 described in step (1) are introduced into the base liquid to carry out a co-precipitation reaction.

[0018] Preferably, the coprecipitation reaction includes a nucleation reaction stage and a growth reaction stage, wherein the third complexing agent solution is stopped being introduced 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, resulting in a higher manganese ion content in the core and reducing manganese ion dissolution.

[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 not limited to the listed values. Other unlisted values ​​within the range are also applicable.

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

[0022] Preferably, during the nucleation reaction stage, the concentration of the third complexing agent solution is 0.1-0.4 g / L, for example, it can be 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. Other unlisted values ​​within the range are also applicable.

[0023] Preferably, during the nucleation reaction stage, the concentration of the first complexing agent solution is 0.2-0.8 g / L, for example, it can be 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. Other unlisted values ​​within the range are also applicable.

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

[0025] Preferably, the base liquid 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℃, for example, 40℃, 50℃ or 60℃, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

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

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

[0029] Preferably, the concentration of the third complexing agent solution in step (1) is 30-50 g / L, for example, it can be 30 g / L, 40 g / L or 50 g / L, but is not limited to the listed values. Other unlisted values ​​within the 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, it can be 1.6 mol / L, 2 mol / L or 2.4 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] Preferably, the concentration of the precipitant solution in step (1) is 9-12 mol / L, for example, it can be 9 mol / L, 10 mol / L, 11 mol / L or 12 mol / L, but is not limited to the listed values. Other unlisted values ​​within the 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, which includes a mixture of oxygen and nitrogen in a volume ratio of (0-5):10, but does not include 0:10. For example, it can be 1:10, 2:10, 4:10 or 5:10, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

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

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

[0036] Preferably, the sintering in step (2) includes first holding at 300-500℃, for example, 300℃, 400℃ or 500℃ for 3-5 hours, for example, 3 hours, 4 hours or 5 hours, and then holding at 700-900℃, for example, 700℃, 800℃ or 900℃ for 7-9 hours, for example, 7 hours, 8 hours or 9 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] As a preferred embodiment of the preparation method of the present invention, the preparation method includes 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 passed into the bottom liquid. The nucleation reaction is carried out at a pH of 11.1-13 for 15-25 h. Then the passage of the third complexing agent solution is stopped, and the growth reaction is carried out at a pH of 9-11 for 80-100 h. Then the particles are aged, separated from solids and liquids, washed, and dried to obtain precursor particles with a particle size D50 of 1-3.5 μm.

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

[0040] (2) Mix the lithium source and the precursor particles described in step (1), then keep it at 300-500℃ for 3-5 hours, and then keep it at 700-900℃ for 7-9 hours to obtain the lithium-rich manganese-based material for solid batteries.

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

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

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

[0044] This invention utilizes a combination of three complexing agents during the preparation of precursor particles, enabling the production of smaller precursor particles. The porphyrin-based complexing agent is used to complement the lithium-rich manganese precursor material. Porphyrin-based complexing agents have a stronger ability to complex manganese ions, thus facilitating the preparation of smaller precursor particles. Therefore, this invention can produce highly dispersed small-particle lithium-rich manganese-based materials, ensuring better contact between the lithium-rich manganese-based material and the solid-state electrolyte, thereby improving the performance of solid-state batteries. Attached Figure Description

[0045] Figure 1 This is a SEM image of the precursor particles described in Embodiment 1 of the present invention. Detailed Implementation

[0046] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0047] Example 1

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

[0049] (1) Prepare a nickel-manganese mixed metal source solution with a total ion concentration of 2 mol / L using manganese sulfate and nickel sulfate, wherein the molar ratio of nickel ions to manganese ions is 25:75. Then, pass the nickel-manganese mixed metal source solution, ammonia water with a concentration of 1 mol / L, citric acid aqueous solution with a concentration of 30 g / L, meso-tetra(4-carboxyphenyl)porphyrin aqueous solution with a concentration of 40 g / L, and liquid alkali solution with a concentration of 10 mol / L into the base solution (the base solution has a pH of 12, ammonia water concentration of 0.5 g / L, citric acid concentration of 3 g / L, and meso-tetra(4-carboxyphenyl)porphyrin concentration of 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 for 20 h at 50 °C, 500 rpm, and pH 11.3. During this process, the concentrations of ammonia water, citric acid aqueous solution, and meso-tetra(4-carboxyphenyl)porphyrin were controlled at 0.5 g / L, 3 g / L, and 0.3 g / L, respectively. The temperature was maintained at 50 °C. Then, the flow of meso-tetra(4-carboxyphenyl)porphyrin aqueous solution was stopped, and the growth reaction was carried out for 90 h at pH 9.5. After the coprecipitation reaction was completed, the mixture was aged, centrifuged, washed, dried, and demagnetized to remove foreign matter, yielding precursor particles with a particle size D50 of 1.5 μm. The SEM image of the precursor particles is shown below. Figure 1 As shown;

[0050] (2) Mix lithium hydroxide and the precursor particles described in step (1), then keep at 400°C for 4 hours, and then keep at 800°C for 8 hours to obtain the lithium-rich manganese-based material for solid-state batteries.

[0051] Example 2

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

[0053] (1) Prepare a nickel-manganese mixed metal source solution with a total ion concentration of 1.6 mol / L using manganese sulfate and nickel sulfate, wherein the molar ratio of nickel ions to manganese ions is 25:75. Then, pass the nickel-manganese mixed metal source solution, ammonia water with a concentration of 5 mol / L, citric acid aqueous solution with a concentration of 20 g / L, meso-tetra(4-carboxyphenyl)porphyrin aqueous solution with a concentration of 30 g / L, and liquid alkali solution with a concentration of 9 mol / L into the base solution (the pH of the base solution is 11.5, the concentration of ammonia water is 0.8 g / L, the concentration of citric acid is 3 g / L, and the concentration of meso-tetra(4-carboxyphenyl)porphyrin is 3 g / L). In a mixture of oxygen and nitrogen at a volume ratio of 2:10 (0.2 g / L), a nucleation reaction was carried out at 60 °C and pH 13 for 15 h. During this period, the concentrations of ammonia water, citric acid aqueous solution, and meso-tetra(4-carboxyphenyl)porphyrin in the system were controlled at 0.8 g / L, 2 g / L, and 0.1 g / L. Then, the flow of meso-tetra(4-carboxyphenyl)porphyrin aqueous solution was stopped, and the growth reaction was carried out at pH 11 for 80 h. After the co-precipitation reaction was completed, the mixture was aged, centrifuged, washed, dried, and demagnetized to remove foreign matter, resulting in precursor particles with a particle size D50 of 1 μm.

[0054] (2) Mix the lithium source and the precursor particles described in step (1), then keep it at 500°C for 3 hours and then at 900°C for 7 hours to obtain the lithium-rich manganese-based material for solid-state batteries.

[0055] Example 3

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

[0057] (1) Prepare a nickel-manganese mixed metal source solution with a total ion concentration of 2.4 mol / L using manganese sulfate and nickel sulfate, wherein the molar ratio of nickel ions to manganese ions is 25:75. Then, pass the nickel-manganese mixed metal source solution, ammonia water with a concentration of 8 mol / L, citric acid aqueous solution with a concentration of 40 g / L, meso-tetra(4-carboxyphenyl)porphyrin aqueous solution with a concentration of 50 g / L, and liquid alkali solution with a concentration of 12 mol / L into the base solution (the base solution has a pH of 11, ammonia water concentration of 1.0 g / L, citric acid concentration of 4 g / L, and meso-tetra(4-carboxyphenyl)porphyrin). In a mixture of oxygen and nitrogen at a volume ratio of 5:10 (0.1 g / L), a nucleation reaction was carried out at 40 °C and pH 13 for 25 h. During this period, the concentrations of ammonia water, citric acid aqueous solution, and meso-tetra(4-carboxyphenyl)porphyrin in the system were controlled at 0.2 g / L, 6 g / L, and 0.4 g / L. Then, the flow of meso-tetra(4-carboxyphenyl)porphyrin aqueous solution was stopped, and the growth reaction was carried out at pH 9 for 100 h. After the co-precipitation reaction was completed, the mixture was aged, centrifuged, washed, dried, and demagnetized to remove foreign matter, resulting in precursor particles with a particle size D50 of 2 μm.

[0058] (2) Mix the lithium source and the precursor particles described in step (1), then keep it at 300°C for 5 hours and then at 700°C for 9 hours to obtain the lithium-rich manganese-based material for solid-state batteries.

[0059] Example 4

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

[0061] Example 5

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

[0063] Example 6

[0064] This embodiment provides a method for preparing lithium-rich manganese-based materials for solid-state batteries. The preparation method is the same as in Example 1, except that the flow of meso-tetra(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 lithium-rich manganese-based materials for solid-state batteries. The preparation method is the same as in Example 1, except that the meso-tetra(4-carboxyphenyl)porphyrin aqueous solution was not introduced during co-precipitation.

[0067] Comparative Example 2

[0068] This comparative example provides a method for preparing lithium-rich manganese-based materials for solid-state batteries. Except for the fact that only ammonia is used as a complexing agent in the nucleation and growth reactions of co-precipitation, the preparation method is the same as in Example 1.

[0069] Comparative Example 3

[0070] This comparative example provides a method for preparing lithium-rich manganese-based materials for solid-state batteries. Except for the fact that only citric acid solution is used as a complexing agent in the co-precipitation nucleation and growth reactions, the preparation method is the same as in Example 1.

[0071] Comparative Example 4

[0072] This comparative example provides a method for preparing lithium-rich manganese-based materials for solid-state batteries. The preparation method is the same as in Example 1, except that only meso-tetra(4-carboxyphenyl)porphyrin aqueous solution is used as a complexing agent in the nucleation and growth reactions of co-precipitation.

[0073] The solid-state battery lithium-rich manganese-based material obtained in the above embodiments and comparative examples was mixed with acetylene black and polyvinylidene fluoride in a mass ratio of 8:1:1. Then, N-methyl-2-pyridinyl ketone was added to prepare a solution, which was then uniformly coated on aluminum foil, dried, and stamped to form battery electrodes. The battery electrodes, elemental lithium sheets, glass fiber separators, solid electrolyte sheets, spring sheets, and battery casing were assembled into a button cell in an Ar gas glove box.

[0074] The obtained batteries were tested for capacity and cycle performance under the following conditions: activation at 2.0-4.8V and 0.1C rate for 3 cycles, followed by 100 cycles at 1C. The cycle specific capacity and capacity retention were obtained, and the test results are shown in Table 1.

[0075] Table 1

[0076] Initial specific capacity (mAh / g) Capacity retention rate (%) 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] As can be seen from Table 1:

[0078] This invention employs three complexing agents for co-precipitation, enabling the preparation of highly dispersed small-particle manganese-rich precursors, thereby improving the performance of lithium-rich manganese-based materials. As shown in Example 1 and Comparative Examples 1-4, if no porphyrin complexing agent is added, or only one complexing agent is used for the co-precipitation reaction, the co-precipitation effect decreases, and the performance of the resulting lithium-rich manganese-based material deteriorates. As shown in Example 1 and Examples 4-5, during the nucleation reaction, the concentration of the porphyrin complexing agent in the system affects its complexing effect, thus affecting the distribution of manganese ions and the performance of the final material. As shown in Example 1 and Example 6, this invention preferably introduces the porphyrin complexing agent only during the nucleation stage, thereby optimizing the distribution of manganese ions, reducing manganese ion dissolution, and thus improving the material's performance.

[0079] In summary, this invention provides a lithium-rich manganese-based material for solid-state batteries, its preparation method, and its application. The preparation method, by using a combination of multiple complexing agents, can prepare a highly dispersed small-particle manganese-rich precursor, thereby enabling the preparation of a highly dispersed small-particle lithium-rich manganese-based material. This ensures better contact between the lithium-rich manganese-based material and the solid electrolyte, thus improving the performance of the solid-state battery.

[0080] The above description is only a specific embodiment 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 conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing lithium-rich manganese-based materials for solid-state batteries, characterized in that, The preparation method includes the following steps: (1) 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 were subjected to a co-precipitation reaction to obtain precursor particles; The first complexing agent solution, the second complexing agent solution, and the third complexing agent solution contain different types of complexing agents, and the third complexing agent solution includes porphyrin complexing agents; The porphyrin complexing agent in step (1) includes water-soluble porphyrin compounds; The water-soluble porphyrin compound includes any one or a combination of at least two of meso-tetra(4-carboxyphenyl)porphyrin, meso-tetra(4-sulfonylphenyl)porphyrin, or meso-tetra(4-trimethylammoniumphenyl)porphyrin; Step (1) The first complexing agent solution includes ammonia; Step (1) The second complexing agent solution includes citric acid; (2) The lithium source and the precursor particles described in step (1) are mixed and sintered to obtain the lithium-rich manganese-based material for solid-state batteries.

2. The preparation method according to claim 1, characterized in that, The pH of the coprecipitation reaction in step (1) is 9-13 and the temperature is 40-60℃.

3. The preparation method according to claim 1 or 2, characterized in that, The nickel-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) are introduced into the bottom liquid to carry out a co-precipitation reaction.

4. The preparation method according to claim 3, characterized in that, The coprecipitation reaction includes a nucleation reaction stage and a growth reaction stage, wherein the third complexing agent solution is stopped being introduced during the growth reaction stage.

5. The preparation method according to claim 4, characterized in that, The pH of the nucleation reaction stage is 11.1-13, and the pH of the growth reaction stage is 9-11.

6. The preparation method according to claim 4, characterized in that, The nucleation reaction takes 15-25 hours, and the growth reaction takes 80-100 hours.

7. The preparation method according to claim 4, characterized in that, During the nucleation reaction stage, the concentration of the third complexing agent solution is 0.1-0.4 g / L.

8. The preparation method according to claim 4, characterized in that, During the nucleation reaction stage, the concentration of the first complexing agent solution is 0.2-0.8 g / L.

9. The preparation method according to claim 4, characterized in that, During the nucleation reaction stage, the concentration of the second complexing agent solution is 2-6 g / L.

10. The preparation method according to claim 4, characterized in that, The base liquid includes water, a precipitant solution, and a first complexing agent solution.

11. The preparation method according to claim 4, characterized in that, The pH of the base solution is 9-12, the ammonia concentration is 0.1-10 g / L, and the temperature is 40-60℃.

12. The preparation method according to claim 1, characterized in that, Step (1) The concentration of the first complexing agent solution is 1-10 mol / L.

13. The preparation method according to claim 1, characterized in that, In step (1), the concentration of the second complexing agent solution is 20-40 g / L.

14. The preparation method according to claim 1, characterized in that, The concentration of the third complexing agent solution in step (1) is 30-50 g / L.

15. The preparation method according to claim 1, characterized in that, The concentration of the nickel-manganese mixed metal source solution in step (1) is 1.6-2.4 mol / L.

16. The preparation method according to claim 1, characterized in that, The concentration of the precipitant solution in step (1) is 9-12 mol / L.

17. The preparation method according to claim 1, characterized in that, The coprecipitation reaction in step (1) is carried out in an oxygen-containing gas.

18. The preparation method according to claim 1, characterized in that, After the coprecipitation reaction described in step (1) was completed, aging, solid-liquid separation, washing and drying were carried out.

19. The preparation method according to claim 1, characterized in that, The precursor particles in step (1) have a particle size D50 of 1-3.5 μm.

20. The preparation method according to claim 1, characterized in that, The sintering in step (2) includes holding at 300-500℃ for 3-5 hours and then holding at 700-900℃ for 7-9 hours.

21. The preparation method according to claim 1, characterized in that, The preparation method includes 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 passed into the bottom liquid. The nucleation reaction is carried out at a pH of 11.1-13 for 15-25 h. Then the passage of the third complexing agent solution is stopped, and the growth reaction is carried out at a pH of 9-11 for 80-100 h. Then the particles are aged, separated from solids and liquids, washed and dried to obtain precursor particles with a particle size D50 of 1-3.5 μm. The first complexing agent solution includes ammonia, the second complexing agent solution includes citric acid, and the third complexing agent solution includes a porphyrin complexing agent; the porphyrin complexing agent includes a water-soluble porphyrin compound. The water-soluble porphyrin compound includes any one or a combination of at least two of meso-tetra(4-carboxyphenyl)porphyrin, meso-tetra(4-sulfonylphenyl)porphyrin, or meso-tetra(4-trimethylammoniumphenyl)porphyrin; (2) Mix the lithium source and the precursor particles described in step (1), then keep it at 300-500℃ for 3-5 hours, and then keep it at 700-900℃ for 7-9 hours to obtain the lithium-rich manganese-based material for solid batteries.

22. 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 using the preparation method described in any one of claims 1-21.

23. A solid-state battery, characterized in that, The solid-state battery includes the lithium-rich manganese-based material for solid-state batteries as described in claim 22.

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