Preparation method of nickel-iron-manganese sodium ion battery precursor

Abstract

The invention discloses a preparation method of a nickel-iron-manganese sodium-ion battery precursor, which comprises the following steps: S1, adding ferrous sulfate into a sulfuric acid solution with the pH value of 0.5-3 to obtain a ferrous sulfate mixed solution; mixing the ferrous sulfate mixed solution with a nickel sulfate solution and a manganese sulfate solution to obtain a ternary solution; s2, nitrogen is introduced into the reaction base solution, then a ternary solution, liquid caustic soda and an ammonia water solution are introduced at the same time, a primary reaction is conducted, and first slurry is obtained; s3, adjusting the flow of the ternary liquid, the liquid caustic soda and the ammonia water solution, introducing the ternary liquid, the liquid caustic soda and the ammonia water solution into the first slurry, and carrying out secondary reaction to obtain second slurry containing particles with the particle size D50 of 3.0-4.0 m; s4, carrying out filter pressing and washing on the second slurry to obtain a nickel-iron-manganese sodium ion battery precursor; according to the preparation method, sulfuric acid with a certain concentration is firstly added when the ferrous sulfate mixed solution is prepared, then ferrous sulfate is added, and cold water is used for washing during subsequent washing, so that the crystallinity of the nickel-iron-manganese ternary precursor is improved, and meanwhile, the layered structure stability of the precursor is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium ion batteries, and in particular to a method for preparing a nickel-iron-manganese sodium ion battery precursor. Background Art

[0002] At present, ternary layered hydroxide materials containing nickel, iron and manganese have excellent electrochemical properties and good thermal stability, and are widely used in the preparation of positive electrode materials for sodium ion batteries.

[0003] In the related art, when preparing nickel-iron-manganese ternary precursors, the small particles have poor sphericity, poor dispersibility, and sphere adhesion. The nickel-iron-manganese material with a large BET morphology is prone to breakage during the sintering process, affecting the cycle life of the sodium battery material.

[0004] Therefore, it is necessary to provide a technical solution for improving the crystallinity and stability of nickel-iron-manganese sodium ion battery precursors to improve the battery's charge and discharge efficiency and the cycle life of sodium battery materials. Summary of the invention

[0005] In view of this, the present application provides a method for preparing a nickel-iron-manganese sodium ion battery precursor, which is used to solve the problem of how to improve the crystallinity and stability of the nickel-iron-manganese sodium ion battery precursor.

[0006] In order to achieve the above technical objectives, this application adopts the following technical solutions: In a first aspect, the present application provides a method for preparing a nickel-iron-manganese sodium ion battery precursor, comprising the following steps: S1. Add ferrous sulfate to a sulfuric acid solution having a pH value of 0.5-3 to obtain a ferrous sulfate mixture; the ferrous sulfate mixture is mixed with a nickel sulfate solution and a manganese sulfate solution to obtain a ternary solution; S2. Nitrogen is introduced into the reaction bottom liquid, and then ternary liquid, liquid alkali and ammonia solution are introduced simultaneously to carry out a reaction to obtain a first slurry; S3. adjusting the flow rate of the ternary liquid, the liquid alkali and the ammonia solution and passing them into the first slurry to perform a secondary reaction to obtain a second slurry comprising particles having a particle size D50 of 3.0-4.0µm; S4. Filter and wash the second slurry to obtain a nickel-iron-manganese sodium ion battery precursor.

[0007] Preferably, in step S1, the concentration of the ternary liquid is 80-100 g / L, the molar ratio of nickel, iron and manganese in the ternary liquid is 30:40:30-40; the ferrous sulfate mixture includes 0.5-2 m 3 of sulfuric acid solution, the concentration of the sulfuric acid solution is 30-40%.

[0008] Preferably, in step S2, the reaction base liquid includes pure water, 30-35wt% liquid alkali, and 12-18wt% ammonia solution; the pH of the reaction base liquid is 9.0-11.0, the ammonia concentration is 5-10g / L, and the alkali concentration is 10-15g / L; the flow rate of the nitrogen introduced is 4-8m³ / h.

[0009] Preferably, in step S2, the flow rates of the ternary liquid, liquid alkali and aqueous ammonia solution are 200-250 L / h, 65-75 L / h and 15-20 L / h respectively.

[0010] Preferably, in step S2, the temperature of the primary reaction is 40-55° C., the stirring speed is 100-380 r / min, and the reaction time is 10-15 h.

[0011] Preferably, in step S2, the ammonia concentration in the first slurry is 5-10 g / L, the alkali concentration is 10-15 g / L, and the pH value is 9.5-10.5.

[0012] Preferably, in step S3, the flow rates of the ternary liquid, liquid alkali and aqueous ammonia solution are 300-350 L / h, 95-105 L / h and 25-35 L / h respectively.

[0013] Preferably, in step S3, the pH value of the second slurry is 9.0-10.5.

[0014] Preferably, in step S4, the washing step is: washing with alkaline solution and pure water alternately.

[0015] In a second aspect, the present application provides a nickel-iron-manganese sodium ion battery precursor.

[0016] The beneficial effects of the present application are as follows: The present application controls the pH value, ammonia concentration, anti-oxidation degree and alkali concentration in the reaction process, as well as the conditions of the ternary reaction process, liquid alkali, ammonia water flow rate, etc., so as to enable small particles to grow in a shorter time, increase the collision frequency and number of collisions between seed particles, and form small particles with high sphericity. The nickel-iron-manganese sodium ion battery precursor has good crystallinity and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the SEM image of the product of Example 1; Figure 2 This is the SEM image of the product of Comparative Example 1. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] The present application provides a method for preparing a nickel-iron-manganese sodium ion battery precursor, comprising the following steps: S1. Add ferrous sulfate to a sulfuric acid solution having a pH value of 0.5-3 to obtain a ferrous sulfate mixture; the ferrous sulfate mixture is mixed with a nickel sulfate solution and a manganese sulfate solution to obtain a ternary solution; S2. Nitrogen is introduced into the reaction bottom liquid, and then ternary liquid, liquid alkali and ammonia solution are introduced simultaneously to carry out a reaction to obtain a first slurry; S3. adjusting the flow rate of the ternary liquid, the liquid alkali and the ammonia solution and passing them into the first slurry to perform a secondary reaction to obtain a second slurry containing particles having a particle size D50 of 3.0-4.0µm; S4. Filter and wash the second slurry to obtain a nickel-iron-manganese sodium ion battery precursor.

[0020] In the present application, by first adding a certain concentration of sulfuric acid and then adding ferrous sulfate when preparing the ferrous sulfate mixture, and washing with cold water during the subsequent washing, the prepared precursor has good sphericity, increased TD, strong particle consistency and no adhesion. The present application improves the crystallinity of the nickel-iron-manganese ternary precursor, while enhancing the stability of the precursor layered structure, thereby improving the charge and discharge efficiency of the battery and the cycle life of the sodium electric material.

[0021] In some embodiments, in step S1, the concentration of the ternary liquid is 80-100 g / L, the molar ratio of nickel, iron and manganese in the ternary liquid is 30:40:30-40; the ferrous sulfate mixture includes 0.5-2 m 3 of sulfuric acid solution, the concentration of the sulfuric acid solution is 30-40%.

[0022] In some embodiments, in step S2, the reaction base liquid includes pure water, 30-35wt% liquid alkali, and 12-18wt% ammonia solution; the pH of the reaction base liquid is 9.0-11.0, the ammonia concentration is 5-10g / L, and the alkali concentration is 10-15g / L; the flow rate of the nitrogen gas is 4-8m³ / h. The purity of the nitrogen gas is ≥99.99%, and the duration of the nitrogen gas is ≥8h.

[0023] In some embodiments, in step S2, the flow rates of the ternary liquid, liquid alkali and aqueous ammonia solution are 200-250 L / h, 65-75 L / h and 15-20 L / h, respectively.

[0024] In some embodiments, in step S2, the temperature of a single reaction is 40-55°C, the stirring speed is 100-380r / min, and the reaction time is 10-15h.

[0025] In some embodiments, in step S2, the ammonia concentration in the first slurry is 5-10 g / L, the alkali concentration is 10-15 g / L, and the pH value is 9.5-10.5.

[0026] After obtaining the first slurry, the flow rates of the ternary liquid, the liquid alkali and the ammonia solution are changed to continue the secondary reaction, and the temperature of the secondary reaction is 40-55°C.

[0027] In some embodiments, in step S3, the flow rates of the ternary liquid, liquid alkali and aqueous ammonia solution are 300-350 L / h, 95-105 L / h and 25-35 L / h, respectively.

[0028] In some embodiments, in step S3, the pH value of the second slurry is 9.0-10.5. At this pH value, after the D50 of the particles grows to 3.0-4.0 µm, the feeding is stopped and the slurry in the reactor is discharged into the aging tank.

[0029] In some embodiments, in step S4, the washing step is: washing alternately with alkaline solution and pure water.

[0030] Specifically, the second slurry is washed by a filter press to remove sodium ions and sulfate ions. The washing process is: 1-5 times of alkaline washing and 1-5 times of cold water (normal temperature) washing respectively, and then drying, screening, and packaging steps are performed to prepare a finished product, which is a nickel-iron-manganese sodium ion battery precursor.

[0031] The present application provides a nickel-iron-manganese sodium ion battery precursor.

[0032] The present solution is further described below through specific embodiments.

[0033] Example 1 A method for preparing a nickel-iron-manganese sodium ion battery precursor comprises the following steps: S1. at 1m 3 , adding 10 mol of ferrous sulfate to a sulfuric acid solution with a pH value of 1 to obtain a ferrous sulfate mixed solution; mixing the ferrous sulfate mixed solution, the nickel sulfate solution, and the manganese sulfate solution in an amount such that the molar ratio of nickel, iron, and manganese metal elements is 30:40:30 and the total concentration of nickel, iron, and manganese metal elements is 100 g / L to obtain a ternary solution; S2. To 6m 34.5m³ of pure water, 30% liquid alkali and 18% ammonia solution were added to the reactor, the pH of the mixed solution of the pure water, liquid alkali and ammonia solution was adjusted to 11.0, the ammonia concentration was 8g / L, 4m³ / h of nitrogen was introduced, the temperature was raised to 45°C and maintained stable, which was the reaction bottom liquid, the stirring speed was set to 350rpm / min, and the ternary liquid, 30% liquid alkali and 18% ammonia solution were accurately added to the reactor at a flow rate of 200L / h, 65L / h and 15L / h respectively through a flow meter, while maintaining 4m³ / h of nitrogen introduction, a reaction was carried out, and the particle D50 continued to grow. After the first reaction lasted for 10h, the pH value dropped to 10.5, the ammonia value was stabilized at 5.0g / L, and the total alkalinity was 10g / L, to obtain the first slurry; S3. Maintaining the reaction conditions in step S2, the reaction was continued until the 24th hour, the flow rates of the ternary liquid, the liquid alkali and the ammonia solution were adjusted to 300 L / h, 95 L / h and 25 L / h, and the reaction was continued until the D50 of the particles grew to 3.3 µm, the feed was stopped, and the second slurry obtained in the reactor was discharged to the aging tank; S4. The second slurry is washed by a filter press to remove sodium ions and sulfate ions, wherein the washing process is 5 times of alkaline washing and 5 times of cold water (normal temperature) washing, respectively, to obtain a nickel-iron-manganese sodium ion battery precursor.

[0034] Example 2 A method for preparing a nickel-iron-manganese sodium ion battery precursor comprises the following steps: S1. at 1m 3 , adding 10 mol of ferrous sulfate to a sulfuric acid solution with a pH value of 1 to obtain a ferrous sulfate mixed solution; mixing the ferrous sulfate mixed solution, the nickel sulfate solution, and the manganese sulfate solution in an amount such that the molar ratio of nickel, iron, and manganese metal elements is 30:40:30 and the total concentration of nickel, iron, and manganese metal elements is 100 g / L to obtain a ternary solution; S2. To 6m 3 4.5m³ of pure water, 35% liquid alkali and 18% ammonia solution were added to the reactor, the pH of the mixed solution of the pure water, liquid alkali and ammonia solution was adjusted to 11.0, the ammonia concentration was 5g / L, 8m³ / h of nitrogen was introduced, the temperature was raised to 45°C and maintained stable, which was the reaction bottom liquid, the stirring speed was set to 350rpm / min, and the ternary liquid, 30-35% liquid alkali and 12%% ammonia solution were accurately added to the reactor at a flow rate of 200L / h, 65L / h and 15L / h respectively through a flow meter, while maintaining 4m³ / h of nitrogen introduction, a reaction was carried out, and the particle D50 continued to grow. After the first reaction lasted for 15h, the pH value dropped to 9.8, the ammonia value was stabilized at 8.0g / L, and the total alkalinity was 15g / L, and the first slurry was obtained; S3. Maintaining the reaction conditions in step S2, the reaction was continued until the 24th hour, the flow rates of the ternary liquid, the liquid alkali and the ammonia solution were adjusted to 300 L / h, 95 L / h and 25 L / h, and the reaction was continued until the D50 of the particles grew to 3.3 µm, the feed was stopped, and the second slurry obtained in the reactor was discharged to the aging tank; S4. The second slurry is washed by a filter press to remove sodium ions and sulfate ions, wherein the washing process is 2 alkaline washings and 2 cold water (normal temperature) washings respectively, to obtain a nickel-iron-manganese sodium ion battery precursor.

[0035] Comparative Example 1 A method for preparing a nickel-iron-manganese sodium ion battery precursor, the other contents are the same as those of Example 1, except that the ferrous sulfate mixture in step S1 does not include the addition of sulfuric acid; and the washing water in step S4 replaces cold water with hot water.

[0036] Test and Evaluation The nickel-iron-manganese sodium ion battery precursors obtained in Example 1 and Comparative Example 1 were examined by electron microscopy, and the results were as follows: Figure 1 , Figure 2 shown.

[0037] The nickel-iron-manganese sodium ion battery precursor obtained in Example and Comparative Example 1 was tested for Na and S content, tap density and specific surface area, and the results are shown in Table 1.

[0038] Table 1 Test results

[0039] From the above data, it can be seen that the present application adds a certain concentration of sulfuric acid and then adds ferrous sulfate when preparing the ferrous sulfate mixture, and washes with cold water during the subsequent washing, so that the prepared precursor has good sphericity, increased TD, strong particle consistency and no adhesion. The present application improves the crystallinity of the nickel-iron-manganese ternary precursor, and at the same time enhances the stability of the precursor layered structure, thereby improving the charge and discharge efficiency of the battery and the cycle life of the sodium electric material.

[0040] The above are only preferred specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a nickel-iron-manganese sodium ion battery precursor, characterized in that: The following steps are involved: S1. Add ferrous sulfate to a sulfuric acid solution having a pH value of 0.5-3 to obtain a ferrous sulfate mixture; the ferrous sulfate mixture is mixed with a nickel sulfate solution and a manganese sulfate solution to obtain a ternary solution; S2. Nitrogen is introduced into the reaction bottom liquid, and then ternary liquid, liquid alkali and ammonia solution are introduced simultaneously to carry out a reaction to obtain a first slurry; S3. adjusting the flow rate of the ternary liquid, the liquid alkali and the ammonia solution and passing them into the first slurry to perform a secondary reaction to obtain a second slurry comprising particles having a particle size D50 of 3.0-4.0µm; S4. Filter and wash the second slurry to obtain a nickel-iron-manganese sodium ion battery precursor.

2. The method for preparing a nickel-iron-manganese sodium ion battery precursor according to claim 1, characterized in that: In step S1, the concentration of the ternary liquid is 80-100 g / L, the molar ratio of nickel, iron and manganese in the ternary liquid is 30:40:30-40; the ferrous sulfate mixture includes 0.5-2 m 3 of sulfuric acid solution, the concentration of the sulfuric acid solution is 30-40%.

3. The method for preparing a nickel-iron-manganese sodium ion battery precursor according to claim 1, characterized in that: In step S2, the reaction base liquid includes pure water, 30-35wt% liquid alkali, and 12-18wt% ammonia solution; the pH of the reaction base liquid is 9.0-11.0, the ammonia concentration is 5-10g / L, and the alkali concentration is 10-15g / L; the flow rate of the nitrogen introduced is 4-8m³ / h.

4. The method for preparing a nickel-iron-manganese sodium ion battery precursor according to claim 1, characterized in that: In step S2, the flow rates of the ternary liquid, liquid alkali and aqueous ammonia solution are 200-250 L / h, 65-75 L / h and 15-20 L / h respectively.

5. The method for preparing a nickel-iron-manganese sodium ion battery precursor according to claim 1, characterized in that: In step S2, the temperature of the primary reaction is 40-55° C., the stirring speed is 100-380 r / min, and the reaction time is 10-15 h.

6. The method for preparing a nickel-iron-manganese sodium ion battery precursor according to claim 1, characterized in that: In step S2, the ammonia concentration in the first slurry is 5-10 g / L, the alkali concentration is 10-15 g / L, and the pH value is 9.5-10.

5.

7. The method for preparing a nickel-iron-manganese sodium ion battery precursor according to claim 1, characterized in that: In step S3, the flow rates of the ternary liquid, liquid alkali and aqueous ammonia solution are 300-350 L / h, 95-105 L / h and 25-35 L / h respectively.

8. The method for preparing a nickel-iron-manganese sodium ion battery precursor according to claim 1, characterized in that: In step S3, the pH value of the second slurry is 9.0-10.

5.

9. The method for preparing a nickel-iron-manganese sodium ion battery precursor according to claim 1, characterized in that: In step S4, the washing step is: washing with alkaline solution and pure water alternately.

10. A nickel-iron-manganese sodium ion battery precursor obtained by the preparation method according to any one of claims 1 to 9.

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