Ferromanganese phosphate, and preparation method therefor and use thereof

Abstract

A preparation method for ferromanganese phosphate, which preparation method comprises: stirring and mixing an iron source, a manganese source and phosphoric acid, adding a phosphorus source thereto, and controlling the pH value to be 3.0-4.0 to prepare a mixed solution; and then charging an ammonia water solution A into a reaction kettle, adding the mixed solution and ammonia water B thereto dropwise at the same time in an inert gas atmosphere, controlling the pH of the whole reaction process to be (7.5-8.0) ± 0.1, and performing co-precipitation to prepare ferromanganese phosphate, wherein the use of the prepared ferromanganese phosphate is as a positive electrode material.

Description

Ferromanganous phosphate and its preparation method and application Technical Field

[0001] The present invention belongs to the technical field of battery positive electrode material manufacturing, and in particular relates to a method for preparing ferromanganese phosphate, ferromanganese phosphate prepared by the preparation method, and application of the ferromanganese phosphate in iron-manganese phosphate lithium batteries. Background Art

[0002] There have been many reports on the preparation methods of lithium iron manganese phosphate battery materials and precursors. The current methods for preparing lithium iron manganese phosphate mainly include high-temperature solid-phase method, sol-gel method and co-precipitation method. Among them, the high-temperature solid-phase method is more widely used and more suitable for industrial production. However, it is difficult to control the nucleation rate of the product phase and the diffusion rate of the phase ions in the solid-phase reaction. Therefore, the synthesized lithium iron manganese phosphate product has poor consistency, uneven particle morphology, wide particle size distribution, and a large amount of waste gas pollution will be generated during the entire high-temperature solid-phase reaction process, mainly NH3, CO2, etc. In order to solve the above shortcomings, the use of co-precipitation method to prepare iron manganese phosphate precursors has become the focus of research.

[0003] Summary of the Invention

[0004] The object of the present invention is to provide a solution to the problem of unstable ratios of various components in current ferromanganese phosphate.

[0005] To achieve the above object, the technical solution adopted by the present invention is, on the one hand, a method for preparing ferromanganese phosphate, comprising the following steps:

[0006] S1. Stir and mix the iron source, manganese source, and phosphoric acid, add a phosphorus source, and control the pH to 3.0-4.0 to prepare a mixed solution;

[0007] S2. Ammonia solution A is added to a reactor, and under an inert gas atmosphere, the mixed solution and ammonia solution B are added dropwise simultaneously, and the pH of the entire reaction process is controlled to be (7.5-8.0) ± 0.1, and ferromanganese phosphate is prepared by coprecipitation.

[0008] Optionally, in step S1, the iron source includes at least one of ferrous sulfate, hydrous ferrous sulfate, ferrous nitrate, and ferrous chloride.

[0009] Optionally, in step S1, the phosphorus source includes at least one of phosphoric acid, sodium phosphate, potassium phosphate, ammonium dihydrogen phosphate and diammonium hydrogen phosphate.

[0010] Optionally, in step S1, the manganese source includes at least one of manganous sulfate, manganous nitrate, manganous chloride and manganous acetate.

[0011] Optionally, the step S1 further includes adding an antioxidant, wherein the antioxidant includes ascorbic acid, and the amount of the added antioxidant is 1% of the mass fraction of the iron source.

[0012] Optionally, in step S1, the molar ratio of the added manganese source to the iron source Mn / Fe is 8:2-2:8, and the molar ratio of the sum of the molar amounts of the added manganese source and the iron source to phosphorus is 1.41-1.43. Preferably, the molar ratio of the manganese source to the iron source Mn / Fe is 7:3-3:7. Further, preferably, the molar ratio of the manganese source to the iron source Mn / Fe is 6:4-4:6.

[0013] Optionally, in step S2, the mass percentage of the ammonia solution A is 16-20%, and the mass percentage of the ammonia solution B is 8-10%.

[0014] Optionally, in step S2, when the mixed solution and ammonia water B are added dropwise, the pH of the system is maintained at 5-8.

[0015] Optionally, in step S2, the ferromanganese phosphate is filtered, washed, dried, flash evaporated, ground, and mixed. The washing, flash evaporated, sintered, mixed, and packaged are all performed under air atmosphere.

[0016] In another aspect, the present invention further provides ferromanganese phosphate, which is prepared by the above-mentioned preparation method.

[0017] On the other hand, the present invention also provides a use of ferromanganese phosphate prepared by the above-mentioned preparation method of ferromanganese phosphate in a manganese iron phosphate lithium battery.

[0018] After the iron source and the manganese source are prepared into a solution, phosphoric acid is added to lower the pH value of the solution, thereby reducing the probability of ferrous ion oxidation. An antioxidant is added to prevent the mixed solution from being easily oxidized during the preparation and addition process.

[0019] The ammonium phosphate salt is added to the mixed solution of the present invention. After the ammonium phosphate salt is dissolved, the ammonium phosphate salt can provide a phosphorus source and utilize the coordination effect of ammonium. 4+ The coordination of Mn and ammonia was solved by imitating the method of adding the ternary precursors at the same time. 2+ ,Fe 2+ In the problem of uniform precipitation of phosphate, Mn 2+ 、Fe 2+ The precipitation rate in the phosphate system is of the same order of magnitude, and the requirements of co-precipitation are met from the perspective of chemical reaction. Finally, the content of the three elements Mn, Fe, and P in the manganese ferrophosphate is uniform and the ratio is stable.

[0020] According to the present invention, an ammonia solution A is first added into a reaction kettle, and the pH of the ammonia solution A is adjusted to 7.5-8.0. Under a nitrogen atmosphere, the mixed solution and the base (ammonia solution B) are simultaneously added dropwise using a peristaltic pump. By fixing the flow rate of the mixed solution at 239 ml / min and controlling the flow rate of the ammonia solution at 80 ml / mins, the pH is controlled to be 7.5±0.1 during the entire addition process.

[0021] The ferromanganese phosphate prepared by the present invention produces hollow balls in the initial synthesis reaction, and the looseness and compactness of the solid balls increase with the extension of the feeding time. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the technical problems solved by the present invention, the technical means adopted, and the technical effects achieved more clearly, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, it should be noted that the drawings described below are only drawings of exemplary embodiments of the present invention. Those skilled in the art can derive drawings of other embodiments based on these drawings without inventive effort.

[0023] FIG1 is a flow chart of a method for preparing ferromanganous phosphate.

[0024] 2A-D are SEM images of ferromanganous phosphate in Example 1.

[0025] 3A-C are SEM images of ferromanganous phosphate in Example 3.

[0026] 4A-D are SEM images of ferromanganous phosphate in Example 4.

[0027] 5A-E are EDS element distribution diagrams of ferromanganese phosphate in Example 1.

[0028] 6A-C are EDS line scans of ferromanganese phosphate in Example 1.

[0029] 7A-E are SEM images of ferromanganous phosphate in Comparative Example 1. DETAILED DESCRIPTION

[0030] The exemplary embodiments of the present invention will now be described more fully with reference to the accompanying drawings. Although each exemplary embodiment can be implemented in a variety of specific ways, it should not be understood that the present invention is limited to the embodiments set forth herein. On the contrary, these exemplary embodiments are provided to make the content of the present invention more complete and to more conveniently convey the inventive concept to those skilled in the art. Under the premise of being consistent with the technical concept of the present invention, the structure, performance, effect or other features described in a specific embodiment may be combined in any suitable manner into one or more other embodiments.

[0031] In the process of introducing specific embodiments, the detailed description of the structure, performance, effect or other features is to enable those skilled in the art to fully understand the embodiments. However, it does not exclude that those skilled in the art can implement the present invention with technical solutions that do not contain the above-mentioned structure, performance, effect or other features under specific circumstances.

[0032] Although the steps in the present invention are arranged with reference numerals, they are not used to limit the order of the steps. Unless the order of the steps is clearly stated or the execution of a certain step requires other steps as a basis, the relative order of the steps can be adjusted. It can be understood that the term "and / or" used herein relates to and encompasses any and all possible combinations of one or more of the associated listed items.

[0033] Unless otherwise specified, the chemical reagents and materials in the present invention are purchased through market channels.

[0034] A preparation method of iron manganese phosphate includes the following steps:

[0035] Stir and mix an iron source, a manganese source, and phosphoric acid, wherein the ratio of the sum of the molar amounts of Mn and Fe to the molar amount of phosphorus is 1.41 - 1.43. The molar ratio of Mn / Fe is 8:2 - 2:8. Then add an antioxidant, and the antioxidant is 1% of the mass fraction of the iron source. Then add a phosphorus source, and control the pH value to be 3.0 - 4.0 throughout the process to prepare a mixed solution; Dilute commercially available ammonia water with pure water to a mass percentage of 16 - 20% at pH 7.5 to prepare an ammonia water solution B. Put an ammonia water solution A with a mass percentage of 16% (diluted 1:1 with pure water) into a reaction kettle, introduce nitrogen, and the reaction temperature is 25 - 40°C. As the temperature rises, the sphericity becomes denser and the primary particles are smaller. At the same time, dropwise add the mixed solution (flow rate of 239 ml / min) and ammonia water B (flow rate of 80 ml / mins), and maintain the pH of the entire reaction system at 5 - 8. The higher the pH value, the smaller the primary and secondary particles. However, if the pH > 9.0, it is difficult to make spherical particles even under the condition of introducing nitrogen. The feeding times are 0.5, 2, 4, 6 h respectively, and the loose bulk density of the solid spheres increases as the feeding time extends. After the feeding is completed, age for 1 hour, and co-precipitate to prepare iron manganese phosphate. The chemical formula of the obtained iron manganese phosphate is (MnxFe1x)3(PO4)2·yH2O, where 0 < x < 1 and 0 ≤ y ≤ 8. Filter, wash, separate and purify the iron manganese phosphate to wash away impurities, and the main impurities include (NH4 4+ , SO4 2- ). Dry, flash vaporize, with an inlet air temperature of 220 ± 5°C and an outlet air temperature of 100 ± 5°C, sinter in a rotary kiln at 610 - 620°C for 3 - 4 h. After the iron manganese phosphate is sintered, mechanically grind and pulverize it, mix it in a mixer, and package it with a packaging machine to obtain a finished product.

[0036] Example 1

[0037] In batching kettle 1, 20,000.00 g of pure water, 500.00 g of phosphoric acid (85%), 5,000 g of ferrous sulfate heptahydrate (20.12%), 4,578.938 g of manganese sulfate (32.42%), and 3,213.15 g of monoammonium phosphate (26.81%) were added and stirred to form a mixed solution. In batching kettle 2, 13,050 g of ammonia water (16%) was diluted with pure water in a 1:1 ratio to form ammonia solution B. The reactor was purged with nitrogen, the reaction temperature was 30°C, and 15,000g of ammonia solution A (pure water adjusted to pH 7.50 with ammonia solution) was added as the base liquid. The mixed solution and ammonia solution B were added to the reactor using 1# and 2# peristaltic pumps, respectively. The flow rate of the 1# peristaltic pump was fixed, and the flow rate of the 2# peristaltic pump was automatically adjusted by pH meter signal feedback to maintain the pH at 7.50±0.1 during the entire feeding process. The feeding time was 4h. The mixed solution and ammonia solution B were added dropwise simultaneously. Nitrogen was continued to be purged in the reactor and the aging reaction was carried out for 1h. After the reaction was completed, the mixture was filtered using a filter press and washed with water (cake: water = 1:4) 7 times. The filter cake was flash dried with a flash inlet air temperature of 220±5°C and an outlet air temperature of 100±5°C. The mixture was sintered in a rotary kiln at 610-620°C for 3-4h. After sintering, the material was mechanically ground and then fed into a mixer and a packaging machine to obtain the finished ferromanganese phosphate. As can be seen from Figures 2A-D, the secondary particles of the prepared ferromanganese phosphate are spherical and solid. Figures 5A-E are EDS element distribution diagrams of ferromanganese phosphate, which show that the three elements Mn, Fe, and P are uniform.

[0038] Figure 6A-C is the EDS line scan of ferromanganese phosphate. It can be seen from the line scan that the three elements Mn, Fe, and P are evenly distributed in ferromanganese phosphate. It can also be seen that the CP surface is flat and the elements are uniform.

[0039] Example 2:

[0040] In batching kettle 1, 20,000.00 g of pure water, 500.00 g of phosphoric acid (85%), 5,000 g of ferrous sulfate heptahydrate (20.12%), 4,578.938 g of manganese sulfate (32.42%), and 3,213.15 g of monoammonium phosphate (26.81%) were added and stirred to form a mixed solution. In batching kettle 2, 13,050 g of ammonia water (16%) was diluted with pure water in a 1:1 ratio to form ammonia solution B. The reactor was purged with nitrogen, the reaction temperature was 30°C, and 15,000g of ammonia solution A (pure water adjusted to pH 7.50 with ammonia solution) was added as the base liquid. The mixed solution and ammonia solution B were added to the reactor using 1# and 2# peristaltic pumps, respectively. The flow rate of the 1# peristaltic pump was fixed, and the flow rate of the 2# peristaltic pump was automatically adjusted by pH meter signal feedback to maintain the pH at 7.50±0.1 during the entire feeding process. The feeding time was 2h. The mixed solution and ammonia solution B were added dropwise simultaneously. Nitrogen was continued to be purged in the reactor and the aging reaction was carried out for 1h. After the reaction was completed, the mixture was filtered using a filter press and washed with water (cake: water = 1:4) 7 times. The filter cake was flash dried with a flash inlet air temperature of 220±5°C and an outlet air temperature of 100±5°C. The mixture was sintered in a rotary kiln at 610-620°C for 3-4h. After sintering, the material was mechanically ground and then fed into a mixer and a packaging machine to obtain the finished ferromanganese phosphate.

[0041] Example 3:

[0042] In batching kettle 1, add 20,000.00 g of pure water, 500.00 g of phosphoric acid (85%), 5,000 g of ferrous sulfate heptahydrate (20.12%), 4,578.938 g of manganese sulfate (32.42%), and 3,213.15 g of monoammonium phosphate (26.81%), and stir the solution to form a mixed solution. In batching kettle 2, dilute ammonia water (16%) with pure water in a 1:1 ratio to form 13,050 g of ammonia solution B. The reactor was purged with nitrogen, the reaction temperature was 30°C, and 15,000g of ammonia solution A (pure water adjusted to pH 7.50 with ammonia solution) was added as the base liquid. The mixed solution and ammonia solution B were added to the reactor using 1# and 2# peristaltic pumps, respectively. The flow rate of the 1# peristaltic pump was fixed, and the flow rate of the 2# peristaltic pump was automatically adjusted by pH meter signal feedback to maintain the pH at 7.50±0.1 during the entire feeding process. The feeding time was 0.5h. The mixed solution and ammonia solution B were added dropwise simultaneously. Nitrogen was continued to be purged in the reactor and the aging reaction was carried out for 1h. After the reaction was completed, the mixture was filtered using a filter press and washed with water (cake: water = 1:4) 7 times. The filter cake was flash dried with a flash inlet air temperature of 220±5°C and an outlet air temperature of 100±5°C. The mixture was sintered in a rotary kiln at 610-620°C for 3-4h. After sintering, the material was mechanically ground and then fed into a mixer and a packaging machine to obtain the finished ferromanganese phosphate. As can be seen from FIG3A-C, the addition time is 0.5 h, and the prepared ferromanganese phosphate is a hollow sphere.

[0043] Example 4:

[0044] In batching kettle 1, add 20,000.00 g of pure water, 500.00 g of phosphoric acid (85%), 5,000 g of ferrous sulfate heptahydrate (20.12%), 4,578.938 g of manganese sulfate (32.42%), and 3,213.15 g of monoammonium phosphate (26.81%), and stir the solution to form a mixed solution. In batching kettle 2, dilute ammonia water (16%) with pure water in a 1:1 ratio to form 13,050 g of ammonia solution B. The reactor was purged with nitrogen, the reaction temperature was 30°C, and 15,000g of ammonia solution A (pure water adjusted to pH 7.50 with ammonia solution) was added as the base liquid. The mixed solution and ammonia solution B were added to the reactor using 1# and 2# peristaltic pumps, respectively. The flow rate of the 1# peristaltic pump was fixed, and the flow rate of the 2# peristaltic pump was automatically adjusted by pH meter signal feedback to maintain the pH at 7.50±0.1 during the entire feeding process. The feeding time was 6h. The mixed solution and ammonia solution B were added dropwise simultaneously. Nitrogen was continued to be purged in the reactor and the aging reaction was carried out for 1h. After the reaction was completed, the mixture was filtered using a filter press and washed with water (cake: water = 1:4) 7 times. The filter cake was flash dried with a flash inlet air temperature of 220±5°C and an outlet air temperature of 100±5°C. The mixture was sintered in a rotary kiln at 610-620°C for 3-4h. After sintering, the material was mechanically ground and then fed into a mixer and a packaging machine to obtain the finished ferromanganese phosphate. As can be seen from Figures 4A-4D, when the feeding time is 6 hours, the prepared ferromanganese phosphate is a solid sphere.

[0045] Example 5:

[0046] Add 20000.00 g of pure water, 500.00 g of phosphoric acid (85%), 5000 g of ferrous sulfate (20.12%), 4578.938 g of manganese sulfate (32.42%), and 3213.15 g of monoammonium phosphate (26.81%) into batching kettle 1, and stir the solution to form a mixed solution; dilute ammonia water (16%) with pure water in a 1:1 ratio in batching kettle 2 to 13050 g, as ammonia solution B. The reactor was purged with nitrogen, the reaction temperature was 35°C, and 15,000g of ammonia solution A (pure water adjusted to pH 7.50 with ammonia solution) was added as the base liquid. The mixed solution and ammonia solution B were added to the reactor using 1# and 2# peristaltic pumps, respectively. By fixing the flow rate of the 1# peristaltic pump, the flow rate of the 2# peristaltic pump was automatically adjusted by pH meter signal feedback to maintain the pH at 7.50±0.1 during the entire feeding process. The feeding time was 4h. The mixed solution and ammonia solution B were added dropwise simultaneously. Nitrogen was continued to be purged in the reactor and the aging reaction was carried out for 1h. After the reaction was completed, the mixture was filtered using a filter press and washed with water (cake: water = 1:4) 7 times. The filter cake was flash dried with a flash inlet temperature of 220±5°C and an outlet temperature of 100±5°C. The mixture was sintered in a rotary kiln at 610-620°C for 3-4h. After sintering, the material was mechanically ground and then fed into a mixer and a packaging machine to obtain the finished ferromanganese phosphate.

[0047] Example 6:

[0048] In batching kettle 1, 20,000.00 g of pure water, 500.00 g of phosphoric acid (85%), 5,000 g of ferrous sulfate heptahydrate (20.12%), 4,578.938 g of manganese sulfate (32.42%), and 3,213.15 g of monoammonium phosphate (26.81%) were added and stirred to form a mixed solution. In batching kettle 2, 13,050 g of ammonia water (16%) was diluted with pure water in a 1:1 ratio to form ammonia solution B. The reactor was purged with nitrogen, the reaction temperature was 40°C, and 15,000g of ammonia solution A (pure water adjusted to pH 7.50 with ammonia solution) was added as the base liquid. The mixed solution and ammonia solution B were added to the reactor using 1# and 2# peristaltic pumps, respectively. The flow rate of the 1# peristaltic pump was fixed, and the flow rate of the 2# peristaltic pump was automatically adjusted by pH meter signal feedback to maintain the pH at 7.50±0.1 during the entire feeding process. The feeding time was 4h. The mixed solution and ammonia solution B were added dropwise simultaneously. Nitrogen was continued to be purged in the reactor and the aging reaction was carried out for 1h. After the reaction was completed, the mixture was filtered using a filter press and washed with water (cake: water = 1:4) 7 times. The filter cake was flash dried with a flash inlet air temperature of 220±5°C and an outlet air temperature of 100±5°C. The mixture was sintered in a rotary kiln at 610-620°C for 3-4h. After sintering, the material was mechanically ground and then fed into a mixer and a packaging machine to obtain the finished ferromanganese phosphate.

[0049] Example 7:

[0050] The difference between this embodiment and embodiment 1 is that the reaction temperature is 25° C., and the other steps and reaction conditions are exactly the same.

[0051] Example 8:

[0052] The difference between this embodiment and embodiment 1 is that the pH value of the reaction is maintained at 7.0±0.1 during the entire addition process, and the other steps and reaction conditions are exactly the same.

[0053] Example 9:

[0054] The difference between this embodiment and embodiment 1 is that the pH value of the reaction is maintained at 8.0±0.1 during the entire addition process, and the other steps and reaction conditions are exactly the same.

[0055] Example 10:

[0056] The difference between this example and Example 1 is that the sum of the molar amounts of manganous sulfate and ferrous sulfate and the molar amount of ammonium dihydrogen phosphate is 1.41, wherein the molar ratio of manganous sulfate to ferrous sulfate is 6:4, and the other steps and reaction conditions are exactly the same.

[0057] Example 11:

[0058] The difference between this embodiment and embodiment 1 is that the mass fraction of ascorbic acid and ferrous sulfate powder is 1%, and the other steps and reaction conditions are exactly the same.

[0059] Comparative Example 1

[0060] This comparative example differs from Example 1 in that the pH was adjusted to 8.5 during the reaction, resulting in oxidation of the raw materials, inability to completely precipitate manganese and iron ions, and a high ion loss rate in the mother liquor. This resulted in a low M / P ratio of 1.435 in the finished ferromanganese phosphate, which does not meet the required M / P ratio range of 1.450-1.465 for the finished ferromanganese phosphate. As can be seen from the SEM images in Figures 7A-E, the morphology of the prepared ferromanganese phosphate is not spherical.

[0061] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0062] It should be noted that for the aforementioned method embodiments, for simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should be aware that the present invention is not limited by the order of the actions described, because according to the present invention, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0063] In the above examples, the endpoints of the disclosed ranges and any values ​​are not limited to the exact ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in this article.

[0064] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0065] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0066] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for preparing ferromanganese phosphate, It is characterized in that The steps include: S1. Stir and mix the iron source, manganese source and phosphoric acid, add the phosphorus source, control the pH value to 3.0-4.0, and prepare a mixed solution; S2. Put ammonia solution A into a reactor, and under an inert gas atmosphere, simultaneously add the mixed solution and ammonia solution B dropwise, control the pH of the entire reaction process to (7.5-8.0) ± 0.1, and prepare ferromanganese phosphate by coprecipitation.

2. The method for preparing ferromanganese phosphate according to claim 1, It is characterized in that In the step S1, the iron source includes at least one of ferrous sulfate, hydrous ferrous sulfate, ferrous nitrate, and ferrous chloride.

3. The method for preparing ferromanganese phosphate according to claim 1, It is characterized in that In the step S1, the phosphorus source includes at least one of phosphoric acid, sodium phosphate, potassium phosphate, ammonium dihydrogen phosphate and diammonium hydrogen phosphate.

4. The method for preparing ferromanganese phosphate according to claim 1, It is characterized in that In the step S1, the manganese source includes at least one of manganous sulfate, manganous nitrate, manganous chloride and manganous acetate.

5. The method for preparing ferromanganese phosphate according to claim 1, It is characterized in that The step S1 further includes adding an antioxidant, wherein the antioxidant includes ascorbic acid, and the amount of the added antioxidant is 1% of the mass fraction of the iron source.

6. The method for preparing ferromanganese phosphate according to claim 1, It is characterized in that In the step S1, the molar ratio of the added manganese source to the iron source Mn / Fe is 8:2-2:8, and the molar ratio of the sum of the molar amounts of the added manganese source and the iron source to phosphorus is 1.41-1.

43.

7. The method for preparing ferromanganese phosphate according to claim 1, It is characterized in that In the step S2, the mass percentage of the ammonia solution A is 16-20%, and the mass percentage of the ammonia solution B is 8-10%.

8. The method for preparing ferromanganese phosphate according to claim 1, It is characterized in that In the step S2, when the mixed solution and ammonia water B are added dropwise, the pH of the system is maintained at 5-8; Preferably, in step S2, the ferromanganese phosphate is filtered, washed, dried, flash evaporated, ground and mixed.

9. A ferromanganese phosphate, Features: The ferromanganese phosphate is prepared by the preparation method described in any one of claims 1-8.

10. Use of ferromanganese phosphate prepared by the method for preparing ferromanganese phosphate according to any one of claims 1 to 8 in a lithium iron manganese phosphate battery.

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