Preparation method of sodium ferromanganese phosphate material

Abstract

The invention discloses a preparation method of a sodium ferromanganese phosphate material. The preparation method comprises the following steps: S1, preparing an ammonium phosphate solution, a manganese source solution and an ammonium persulfate solution; s2, taking the ammonium phosphate solution as a base solution, heating to 90-100 DEG C while stirring, then separately and synchronously adding the manganese source solution and the ammonium persulfate solution, and reacting to obtain manganese phosphate monohydrate slurry; s3, filtering and washing the manganese phosphate monohydrate slurry, drying the washed material, and mixing and shearing to a target particle size; s4, adding a powder iron source and a powder sodium salt, mixing and shearing to reach a target particle size, adding a powder carbon source, and continuously mixing and shearing until the required particle size is obtained; and S5, carrying out high-temperature sintering on the mixed dry powder under gas protection to obtain the sodium ferromanganese phosphate material. The preparation method disclosed by the invention has the advantages of cheap and easily available raw materials, simple process, convenience in operation, low energy consumption and the like, and the obtained sodium ferromanganese phosphate material has the advantages of high crystallinity, high compaction and good electrical property.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy and sodium batteries, and in particular to a method for preparing a sodium ferromanganese phosphate material. Background Art

[0002] Compared to lithium-ion batteries, sodium-ion batteries (SIBs) have the advantages of low cost, improved safety, and superior low-temperature and rate performance. In recent years, they have gradually become a hot topic for research and industrial applications. Although sodium ions have a larger radius than lithium ions, their Stokes radius is smaller than that of lithium ions, resulting in faster transport in the electrolyte. In sodium-ion batteries, polyanion cathode materials have lower costs, higher safety performance, and higher energy density than other cathode materials, such as ternary sodium batteries and Prussian materials, making them the mainstream materials for industrial applications. Sodium manganese iron phosphate materials have attracted widespread attention due to their higher discharge voltage, higher compaction density, lower cost, and environmental friendliness.

[0003] CN109659525 uses an electrospinning method to prepare sodium manganese ferrophosphate. The method involves mixing a sodium source, an iron source, a manganese source, a phosphoric acid source, a fluorine source, a chelating agent, and a polymer to form a spinning solution. This solution is then electrospun to obtain a precursor. A conductive polymer is then added, stirred, filtered, washed, and dried to obtain the sodium manganese ferrophosphate product. This method requires the use of organic solvents and polymers, making wastewater treatment difficult. Furthermore, the electrospinning method has limited production capacity and is difficult to meet the requirements of large-scale industrialization.

[0004] In CN117673330 A, a phosphorus source, a manganese source, an iron source I, a metal doping compound, a reducing agent, etc. are mixed and reacted to obtain a slurry containing phosphorus, iron, and manganese; the slurry is then mixed with a sodium source, a carbon source, and an iron source II through ball milling, sand milling, spray drying, pre-calcination, roller pressing, and secondary sintering to obtain a sodium manganese ferrophosphate pyrophosphate product. However, this method has a long process flow and high energy consumption. Summary of the Invention

[0005] The present invention aims to solve one of the technical problems existing in the production and preparation of existing sodium cathode materials. The present invention provides a method for preparing sodium ferromanganese phosphate material.

[0006] A method for preparing a sodium ferromanganese phosphate material according to an embodiment of the present invention comprises the following steps: S1. Prepare ammonium phosphate solution, manganese source solution and ammonium persulfate solution.

[0007] S2. Add the ammonium phosphate solution into the reactor as a base solution, heat it to 90-100° C. while stirring, then slowly add the manganese source solution and the ammonium persulfate solution into the reactor separately and synchronously. After reacting for a period of time, a manganese phosphate monohydrate slurry is obtained.

[0008] S3. The slurry is filtered and washed. The washed material is dried and then added to a high-speed mixing and shearing machine for mixing and shearing without adding any other solvents. The material is mixed and sheared to the target particle size.

[0009] S4. Add powdered iron source and powdered sodium salt to a high-speed mixing and shearing machine. After mixing and shearing for a period of time to reach the target particle size, add powdered carbon source and work for a period of time until the desired particle size is obtained.

[0010] S5. The mixed dry powder is sintered at high temperature in a roller kiln under gas protection to obtain the desired sodium ferromanganese phosphate product.

[0011] Preferably, the ammonium phosphate solution in step S1 is at least one of monoammonium phosphate and diammonium phosphate solutions, and the manganese source solution is selected from at least one of manganese sulfate, manganese chloride and manganese nitrate solutions.

[0012] Preferably, the molar ratio of phosphorus, manganese and ammonium persulfate in the ammonium phosphate solution and the manganese source solution in step S1 is 1-1.5:1:0.5-1.0.

[0013] Preferably, in step S2, the stirring speed of the reactor is 50-150 rpm, the manganese source and ammonium persulfate are added simultaneously for 5-8 hours, and the reaction time after the addition is 2-4 hours.

[0014] Preferably, in step S3, the slurry is washed until the conductivity of the washing water is less than 800 μs / cm, the inlet air temperature during drying is 130-180°C, the outlet air temperature is 80-100°C, the classifier frequency is 20-50 Hz, the high-speed mixing speed is 500-1000 rpm, the shear speed is 3000-5000 rpm, and the target particle size is 200-500 nm.

[0015] Preferably, the powdered iron source in step S4 is at least one of ferric phosphate, iron powder, red iron oxide, and ferrosoferric oxide; the powdered sodium source is at least one of sodium carbonate, sodium bicarbonate, and sodium chloride; and the powdered carbon source is at least one of fructose, glucose, and sucrose.

[0016] Preferably, the target particle size after adding the powdered iron source and the powdered sodium source in step S4 is 200-300 nm, and the target particle size after adding the powdered carbon source is 150-250 nm.

[0017] Preferably, the protective gas in step S5 is at least one of nitrogen, argon, and helium, preferably nitrogen. During sintering in a roller kiln, the temperature in the heating section is 500-700°C, the temperature in the constant temperature section is 800-900°C, and the temperature in the cooling section is 200-300°C. The total sintering time is 15-20 hours, and the sodium ferromanganese phosphate product is obtained after sintering.

[0018] The solution of the present invention first generates a manganese phosphate monohydrate precipitate, which is filtered, washed, and dried, and then mixed and sheared with an iron source, a sodium source, and a carbon source. The mixed and sheared materials are sintered at high temperature to obtain the desired sodium ferromanganese phosphate product. The preparation method has the advantages of cheap and readily available raw materials, simple process, convenient operation, and low energy consumption. The obtained sodium ferromanganese phosphate material has the advantages of high crystallinity, high compaction, and good electrical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the XRD pattern of the sodium ferromanganese phosphate material prepared in Example 3 of the present invention; Figure 2 This is an SEM image of the sodium ferromanganese phosphate material prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0020] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. Those who do not specify specific conditions in the embodiments are carried out according to normal conditions or the conditions recommended by the manufacturer. Those whose reagents or instruments are not specified by the manufacturer are conventional products that can be purchased commercially.

[0021] <Example 1> A method for preparing sodium ferromanganese phosphate material comprises the following steps: 1. Prepare 600 L of 1 mol / L monoammonium phosphate solution, 500 L of 1 mol / L manganese sulfate solution, and 500 L of 0.5 mol / L ammonium persulfate solution.

[0022] 2. Add monoammonium phosphate solution to the reactor as a primer, heat it to 90-100°C with stirring, and stir at a speed of 100 rpm. Then, add manganese sulfate solution and ammonium persulfate solution separately and slowly to the reactor simultaneously. The addition time is 7 hours. After reacting for 3 hours, a manganese phosphate monohydrate slurry is obtained.

[0023] 3. The slurry is filtered and washed until the conductivity of the washing water is less than 800us / cm. The washed material is dried at an air inlet temperature of 130°C, an air outlet temperature of 80°C, and a classifier frequency of 20Hz. After drying, the slurry is added to a high-speed mixing and shearing machine for mixing and shearing without adding any other solvents. The high-speed mixing speed is 800rpm, the shearing speed is 4000rpm, and the target particle size is 300nm.

[0024] 4. Add 22.8 kg of powdered ferric phosphate and 45 kg of sodium carbonate into a high-speed mixing and shearing machine. After mixing and shearing for a period of time until the particle size reaches 300 nm, add 1.2 kg of powdered glucose and continue mixing for a period of time until the particle size reaches 250 nm.

[0025] 5. The mixed dry powder is sintered at high temperature in a roller kiln under gas protection. Nitrogen is used as the protective gas. During the sintering in the roller kiln, the temperature of the heating section is 500°C, the temperature of the constant temperature section is 850°C, the temperature of the cooling section is 200-300°C, and the total sintering time is 17 hours to obtain the desired sodium ferromanganese phosphate product.

[0026] <Example 2> A method for preparing sodium ferromanganese phosphate material comprises the following steps: 1. Prepare 1200 L of 1 mol / L monoammonium phosphate solution, 1000 L of 1 mol / L manganese sulfate solution, and 1000 L of 0.5 mol / L ammonium persulfate solution.

[0027] 2. Add monoammonium phosphate solution to the reactor as a primer, heat it to 90-100°C with stirring, and stir at a speed of 100 rpm. Then, add manganese sulfate solution and ammonium persulfate solution separately and slowly to the reactor simultaneously. The addition time is 8 hours. After reacting for 4 hours, a manganese phosphate monohydrate slurry is obtained.

[0028] 3. The slurry is filtered and washed until the conductivity of the washing water is less than 800us / cm. The washed material is dried at an inlet air temperature of 180°C, an outlet air temperature of 100°C, and a classifier frequency of 50Hz. After drying, the slurry is added to a high-speed mixing and shearing machine for mixing and shearing without adding any other solvents. The high-speed mixing speed is 1000rpm, the shearing speed is 5000rpm, and the target particle size is 300nm.

[0029] 4. Add 50kg of powdered iron oxide red and 92kg of sodium carbonate into a high-speed mixing and shearing machine. After mixing and shearing for a period of time until the particle size reaches 300nm, add 2.4kg of powdered fructose and continue mixing for a period of time until the particle size reaches 200nm.

[0030] 5. The mixed dry powder is sintered at high temperature in a roller kiln under gas protection. Nitrogen is used as the protective gas. During the sintering in the roller kiln, the temperature of the heating section is 500-700°C, the temperature of the constant temperature section is 850°C, the temperature of the cooling section is 200-300°C, and the total sintering time is 17 hours to obtain the desired sodium ferromanganese phosphate product.

[0031] <Example 3> A method for preparing sodium ferromanganese phosphate material comprises the following steps: 1. Prepare 3600 L of 1 mol / L monoammonium phosphate solution, 3000 L of 1 mol / L manganese sulfate solution, and 3000 L of 0.5 mol / L ammonium persulfate solution.

[0032] 2. Add monoammonium phosphate solution to the reactor as a primer, heat it to 90-100°C with stirring, and stir at a speed of 100 rpm. Then, add manganese sulfate solution and ammonium persulfate solution separately and slowly to the reactor simultaneously. The addition time is 5 hours. After reacting for 2 hours, a manganese phosphate monohydrate slurry is obtained.

[0033] 3. The slurry is filtered and washed until the conductivity of the washing water is less than 800us / cm. The washed material is dried at an air inlet temperature of 150°C, an air outlet temperature of 90°C, and a classifier frequency of 35Hz. After drying, the slurry is added to a high-speed mixing and shearing machine for mixing and shearing without adding any other solvents. The high-speed mixing speed is 800rpm, the shearing speed is 4000rpm, and the target particle size is 300nm.

[0034] 4. Add 151kg of powdered ferroferric oxide and 276kg of sodium carbonate into a high-speed mixing and shearing machine. After mixing and shearing for a period of time until the particle size reaches 300nm, add 10kg of powdered sucrose and continue mixing for a period of time until the particle size reaches 150nm.

[0035] 5. The mixed dry powder is sintered at high temperature in a roller kiln under gas protection. Nitrogen is used as the protective gas. During the roller kiln sintering, the temperature of the heating section is 500-700°C, the temperature of the constant temperature section is 850°C, and the temperature of the cooling section is 200-300°C. The total sintering time is 17 hours to obtain the desired sodium manganese iron phosphate product. Then, a small amount of sample is taken for XRD and SEM detection.

[0036] The sodium manganese iron phosphate prepared in Examples 1-3 was tested for compaction density, then prepared into button-type batteries under the same conditions, and then its electrical properties were tested under the same conditions according to conventional methods in the art. The electrical performance test results of Examples 1-3 are shown in Table 1 below: Table 1 Comparison of electrical properties

[0037] As can be seen from Table 1, the sodium ferromanganese phosphate prepared in the example has a high compaction density, close to 2.50 g / cc, and good electrical properties. The 0.1C discharge capacity reaches 148-153 mAh / g. The prepared sodium ferromanganese phosphate product has a high capacity and thus a high energy density. The process operation is simple and has the ability to be industrialized.

[0038] The above implementation cases are only for illustrating the technical solutions and features of the present invention, and their purpose is to enable people familiar with the technology to implement them better. They cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention are within the scope of protection of the present invention. The ones not described in detail are prior art.

Claims

1. A method for preparing sodium ferromanganese phosphate material, characterized in that: The following steps are involved: S1, prepare ammonium phosphate solution, manganese source solution and ammonium persulfate solution; S2. The ammonium phosphate solution is used as a base solution, and the temperature is raised to 90-100° C. under stirring, and then the manganese source solution and the ammonium persulfate solution are added separately and simultaneously to obtain a manganese phosphate monohydrate slurry after reaction; S3, filtering and washing the manganese phosphate monohydrate slurry, drying the washed material and adding it to a high-speed mixing and shearing machine for mixing and shearing to a target particle size; S4. Add powdered iron source and powdered sodium salt to a high-speed mixing and shearing machine. After mixing and shearing to reach the target particle size, add powdered carbon source and continue mixing and shearing until the desired particle size is obtained; S5. Sintering the mixed dry powder at high temperature under gas protection to obtain the sodium ferromanganese phosphate material.

2. The method for preparing a sodium ferromanganese phosphate material according to claim 1, wherein: The ammonium phosphate solution in step S1 is at least one of monoammonium phosphate and diammonium phosphate solutions, and the manganese source solution is selected from at least one of manganese sulfate, manganese chloride and manganese nitrate solutions.

3. The method for preparing a sodium ferromanganese phosphate material according to claim 1, wherein: In step S1, the molar ratio of phosphorus, manganese and ammonium persulfate in the ammonium phosphate solution and the manganese source solution is (1-1.5):1:(0.5-1.0).

4. The method for preparing a sodium ferromanganese phosphate material according to claim 1, wherein: Step S2 is carried out in a reactor with a stirring speed of 50-150 rpm. The manganese source solution and the ammonium persulfate solution are added simultaneously for 5-8 hours, and the reaction time after the addition is 2-4 hours.

5. The method for preparing a sodium ferromanganese phosphate material according to claim 1, wherein: In step S3, the slurry is washed until the conductivity of the washing water is less than 800 μs / cm. During drying, the inlet air temperature is 130-180°C, the outlet air temperature is 80-100°C, the classifier frequency is 20-50 Hz, the high-speed mixing speed is 500-1000 rpm, the shear speed is 3000-5000 rpm, and the target particle size is 200-500 nm.

6. The method for preparing a sodium ferromanganese phosphate material according to claim 1, wherein: The powdered iron source in step S4 is at least one of ferric phosphate, iron powder, red iron oxide, and ferrosoferric oxide; the powdered sodium source is at least one of sodium carbonate, sodium bicarbonate, and sodium chloride; and the powdered carbon source is at least one of fructose, glucose, and sucrose.

7. The method for preparing a sodium ferromanganese phosphate material according to claim 1, wherein: The target particle size after adding the powdered iron source and the powdered sodium source in step S4 is 200-300 nm, and the target particle size after adding the powdered carbon source is 150-250 nm.

8. The method for preparing a sodium ferromanganese phosphate material according to claim 1, wherein: The protective gas in step S5 is at least one of nitrogen, argon and helium.

9. The method for preparing a sodium ferromanganese phosphate material according to claim 1, wherein: Step S5 is to perform high-temperature sintering in a roller kiln. During sintering, the temperature of the heating section is 500-700°C, the temperature of the constant temperature section is 800-900°C, the temperature of the cooling section is 200-300°C, and the total sintering time is 15-20h. After sintering, the sodium ferromanganese phosphate product is obtained.

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