A method for continuously and efficiently preparing nanoscale cobalt oxyhydroxide and tricobalt tetraoxide and application thereof

Abstract

This invention discloses a continuous and efficient method for preparing nano-sized cobalt hydroxyl oxide and cobalt tetroxide, and their applications. The method includes the following steps: (1) adding a cobalt salt solution, an oxidant, and a precipitant to a complexing agent and a solvent, and stirring to obtain a reactant; (2) drying the reactant at 150-160°C to obtain the cobalt hydroxyl oxide; and drying the reactant at 220-230°C to obtain the cobalt tetroxide. Compared with batch production methods, the continuous method of this invention has higher production efficiency, and the prepared cobalt hydroxyl oxide has advantages such as large specific surface area, easy crushing, and small particle size.

Description

Technical Field

[0001] This invention belongs to the field of batteries, specifically relating to a method for the continuous and efficient preparation of nano-scale cobalt hydroxyl oxide and cobalt tetroxide, and their applications. Background Technology

[0002] Surface coating technology is one of the most significant and convenient methods to improve the overall performance of ternary cathode materials, including cycle stability, thermal stability, and safety. However, current production processes are mostly batch-based, resulting in low efficiency, and insufficient specific surface area is a current challenge for cobalt hydroxyl oxide materials. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a continuous and efficient method for preparing nano-sized cobalt hydroxyl oxide and cobalt tetroxide.

[0004] The present invention also proposes nanoscale cobalt hydroxyoxide prepared by the above method.

[0005] The present invention also proposes a method for preparing cobalt tetroxide.

[0006] The present invention also proposes applications of the above method.

[0007] According to a first aspect of the present invention, a method for the continuous and efficient preparation of nano-sized cobalt hydroxyl oxide and cobalt tetroxide is provided, the method comprising the following steps: (1) Add cobalt salt solution, oxidant and precipitant to complexing agent and solvent, stir to react and obtain reactants; (2) The reactants are dried at 150-160°C to obtain cobalt hydroxyl oxide; the reactants are dried at 220-230°C to obtain cobalt tetroxide.

[0008] In some embodiments of the present invention, the cobalt salt solution includes one or more of cobalt chloride aqueous solution, cobalt sulfate aqueous solution, and cobalt nitrate aqueous solution.

[0009] In some embodiments of the present invention, the concentration of the cobalt salt solution is 1.3-1.7 mol / L.

[0010] In some embodiments of the present invention, the complexing agent includes one or more of ammonia, potassium hydroxide aqueous solution, sodium hydroxide aqueous solution, and lithium hydroxide aqueous solution.

[0011] In some embodiments of the present invention, the complexing agent is ammonia.

[0012] In some embodiments of the present invention, the concentration of the complexing agent is 8 to 9 mol / L.

[0013] In some embodiments of the present invention, the solvent includes water.

[0014] In some embodiments of the present invention, the oxidant includes one or more of hydrogen peroxide, ammonium persulfate, sodium hypochlorite, sodium perchlorate, sodium persulfate, sodium peroxide, and ozone.

[0015] In some embodiments of the present invention, the oxidant is sodium persulfate.

[0016] In some embodiments of the present invention, the concentration of the oxidant is 8 to 9 mol / L.

[0017] In some embodiments of the present invention, the precipitant includes potassium hydroxide and sodium hydroxide.

[0018] In some embodiments of the present invention, the concentration of the precipitant is 10 to 11 mol / L.

[0019] In some embodiments of the present invention, the molar mass ratio of the cobalt salt to the oxidant is (1-4):1. Optionally, the molar mass ratio of the cobalt salt to the oxidant can be any value between 1:1, 2:1, 3:1, 4:1, and (1-4):1.

[0020] In some embodiments of the present invention, the molar mass ratio of the cobalt salt to the complexing agent is (1-10):1. Optionally, the molar mass ratio of the cobalt salt to the oxidizing agent can be any value between 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, and (1-10):1.

[0021] The optimal selection and dosage control of each raw material can better control the reaction process and obtain cobalt hydroxyl oxide and cobalt tetroxide with better specific surface area and performance.

[0022] In some embodiments of the present invention, the stirring speed of the stirring reaction is 350-450 rpm.

[0023] In some embodiments of the present invention, the stirring speed of the stirring reaction is 395-405 rpm. Optionally, the stirring speed of the stirring reaction can be any value between 395, 400, 405, and 395-405 rpm.

[0024] In some embodiments of the present invention, the temperature of the stirring reaction is 45–55°C. Optionally, the temperature of the stirring reaction can be any value between 45°C, 50°C, 55°C, and 45–55°C.

[0025] In some embodiments of the invention, the pH of the stirring reaction is greater than 12.5.

[0026] In some embodiments of the present invention, a step of washing the reactants is further included, the step of washing the reactants with hot pure water at 75-85°C.

[0027] In some embodiments of the present invention, the reactants are recovered using a reflux method.

[0028] In some embodiments of the present invention, the moisture content of the dried cobalt hydroxyoxide is <1.5%.

[0029] In some embodiments of the present invention, the method further includes a step of pulverizing the dried cobalt hydroxyl oxide and cobalt tetroxide.

[0030] In some embodiments of the present invention, the pulverization includes coarse pulverization using a roller mill followed by fine pulverization using an air jet mill.

[0031] In some embodiments of the present invention, the D50 of the cobalt hydroxyl oxide and cobalt tetroxide is 0.01-0.5 μm, and the Dmax is ≤5 μm; In some embodiments of the present invention, a step of demagnetizing the pulverized cobalt hydroxyoxide and cobalt tetroxide is further included, wherein the magnetic content of the cobalt hydroxyoxide and cobalt tetroxide is ≤70ppb.

[0032] In some embodiments of the present invention, the step involves drying the reactants at 150-160°C to obtain the cobalt hydroxyoxide. The specific temperature can be 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, or 160°C.

[0033] In some embodiments of the present invention, the step involves drying the reactants at 220-230°C, specifically at temperatures of 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, or 230°C.

[0034] According to a second aspect of the present invention, a cobalt hydroxyoxide is provided, which is prepared using the aforementioned preparation method.

[0035] In some embodiments of the present invention, the cobalt hydroxyoxide has a particle size of 0.01-5 μm.

[0036] In some embodiments of the present invention, the cobalt hydroxyoxide has a particle size of 0.01-0.5 μm.

[0037] In some embodiments of the present invention, the specific surface area of ​​the cobalt hydroxyoxide is 100-180 m². 2 / g.

[0038] According to a third aspect of the present invention, a cobalt tetroxide is provided, which is prepared using the aforementioned preparation method.

[0039] In some embodiments of the present invention, the particle size of the cobalt tetroxide is 0.01-5 μm.

[0040] In some embodiments of the present invention, the particle size of the cobalt tetroxide is 0.01-0.5 μm.

[0041] According to a fourth aspect of the present invention, an application of the above method in the preparation of cobalt hydroxyoxide and / or cobalt tetroxide is proposed.

[0042] According to some embodiments of the present invention, at least the following beneficial effects are achieved: The present invention provides a continuous and efficient method for preparing nano-sized cobalt hydroxyl oxide and cobalt tetroxide. This involves preparing a cobalt salt solution of a certain concentration, a precipitant, a complexing agent, and an oxidant; adding a certain amount of pure water, an appropriate amount of precipitant and complexing agent to a reaction vessel, raising the vessel temperature to a certain level, and starting stirring; sequentially introducing the oxidant, precipitant, complexing agent, and cobalt salt solution into the vessel. The pH is controlled to ≥12.5 by the precipitant until the liquid level in the vessel reaches 75%, at which point the discharge pump is started to continuously discharge the material. The pH value is controlled by the precipitant flow rate, thereby adjusting the particle size D50 ≤3μm in the vessel. After the transfer tank is full, the material is washed, dried, coarsely crushed, finely crushed, demagnetized, and packaged. Compared with batch production methods, the continuous production method of the present invention has higher production efficiency and produces cobalt hydroxyl oxide with a large specific surface area (100-180m²). 2 The cobalt hydroxyoxide prepared in this invention has advantages such as easy crushing, small particle size (D50: 0.01~0.5μm, Dmax≤5μm), etc. As a coating agent for ternary materials, it has significant advantages in the field of lithium-ion batteries, reducing battery internal resistance, improving electronic conductivity, charge / discharge efficiency and power performance, and improving thermal stability. Attached Figure Description

[0043] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a SEM image of cobalt hydroxyoxide oxidized by normal ammonium persulfate in an embodiment of the present invention; Figure 2 This is a SEM image of cobalt hydroxyl oxide oxidized by ammonium persulfate at an excess flow rate of 1.65 times in an embodiment of the present invention. Figure 3 This is a SEM image of cobalt hydroxyl oxide oxidized by normal sodium persulfate in an embodiment of the present invention; Figure 4 This is a SEM image of cobalt hydroxyl oxide oxidized by sodium persulfate at an excess flow rate of 1.5 times in an embodiment of the present invention. Figure 5 This is an XRD pattern of cobalt hydroxyl oxide oxidized by normal sodium persulfate in an embodiment of the present invention; Figure 6 The image shows the XRD pattern of cobalt hydroxyl oxide oxidized by sodium persulfate at an excess flow rate of 1.5 times in an embodiment of the present invention. Figure 7 This is a SEM image of cobalt hydroxyl oxide obtained at an ammonia flow rate of 0 L / min in an embodiment of the present invention. Figure 8 The image shows a SEM image of cobalt hydroxide obtained with an ammonia flow rate of 0.0058 L / min in an embodiment of the present invention. Figure 9 This is a SEM image of cobalt hydroxide obtained with an ammonia flow rate of 0.01 L / min in an embodiment of the present invention. Figure 10 The image shows a SEM image of cobalt hydroxide obtained with an ammonia flow rate of 0.012 L / min in an embodiment of the present invention. Figure 11 The image shows a SEM image of cobalt hydroxide obtained with an ammonia flow rate of 0.047 L / min in an embodiment of the present invention. Figure 12 This is a flowchart of a conventional solid-liquid separation process in an embodiment of the present invention; Figure 13 This is a flowchart of the cyclic recirculation method in an embodiment of the present invention; Figure 14 The image shows the XRD pattern of cobalt hydroxyl oxide obtained at a drying temperature of 150°C in this embodiment of the invention. Figure 15 The image shows the XRD pattern of cobalt hydroxyl oxide obtained at a drying temperature of 180°C in this embodiment of the invention. Figure 16 The image shows the XRD pattern of cobalt hydroxyl oxide obtained at a drying temperature of 200°C in this embodiment of the invention. Figure 17 The image shows the XRD pattern of cobalt tetroxide obtained at a drying temperature of 220°C in this embodiment of the invention. Figure 18 This is a process flow diagram in an embodiment of the present invention. Detailed Implementation

[0044] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0045] Example 1: A continuous and efficient method for preparing nano-sized cobalt hydroxyl oxide and cobalt tetroxide and its application. This embodiment provides a method for the continuous and efficient preparation of nano-sized cobalt hydroxyl oxide and cobalt tetroxide, the specific steps of which are as follows: 1. Preparation of the metal liquid: The metal liquid is a cobalt salt solution, and the molar concentration of the metal ions in the metal liquid is 1.3–1.7 mol / L; Prepare sodium hydroxide or potassium hydroxide with a molar concentration of 10–11 mol / L as a precipitating agent; Prepare ammonia solution with a molar concentration of 8–9 mol / L as a complexing agent; Prepare sodium persulfate with a molar concentration of 1.25–1.68 mol / L as an oxidizing agent; 2. Add 150-250L of pure water to the reactor, add a precipitant to adjust the pH to 12.5±0.1, add a complexing agent, start stirring, and raise the reactor temperature to 45-55℃; 3. Inject the precipitant into the reactor at a flow rate of 0.2–0.6 L / min; inject the oxidant into the reactor at a flow rate of 0.20–0.99 L / min; inject the complexing agent into the reactor at a flow rate of 0.01–0.03 L / min; inject the cobalt salt solution into the reactor at a flow rate of 0.55–1.65 L / min; during this process, adjust the flow rate of the precipitant to ensure that the pH in the reactor is ≥12.5. 4. When the liquid level in the reactor reaches 700-800L, turn on the discharge pump to transfer the material to the transfer tank; 5. Start cleaning the material when the liquid level in the intermediate transfer tank reaches 50%; 6. When cleaning materials, turn on the feed pump, open the reflux valve, and turn on the reflux pump. The purpose of this step is to wait for the material to form a filter cake layer on the filter cloth to effectively reduce material loss. When the discharged mother liquor is clear and contains very little material, spin dry, and then pass in 75-85℃ hot pure water to wash away S and Na impurities in the material. 7. After cleaning, the qualified materials are dried in an oven at 150-160℃ until the moisture content is less than 1.5%. At this temperature, the material is pure cobalt hydroxyl oxide. If the drying temperature is adjusted to 220-230℃, the material will be pure cobalt tetroxide. 8. The dried material is coarsely crushed using a roller mill. The particle size D50 of the crushed material is 1.5~3.5μm. 9. The coarsely crushed material is then finely crushed using an air jet mill. The particle size of the crushed material is D50: 0.01-0.5μm, Dmax≤5μm. 10. The finely pulverized material is demagnetized, and the magnetic content is ≤70ppb; 11. Pack the demagnetized materials.

[0046] The system flowchart used in this method is as follows: Figure 18 As shown.

[0047] Example 2: A continuous and efficient method for preparing nano-sized cobalt hydroxyl oxide and cobalt tetroxide and its application. This embodiment provides a method for the continuous and efficient preparation of nano-sized cobalt hydroxyl oxide and cobalt tetroxide, the specific steps of which are as follows: 1. Preparation of the metal solution: The metal solution is a cobalt sulfate solution, and the molar concentration of the metal ions in the metal solution is 1.3 to 1.7 mol / L (specifically 1.5 mol / L in this embodiment). Prepare sodium hydroxide with a molar concentration of 10–11 mol / L (specifically 10 mol / L in this example) as a precipitant; Prepare ammonia solution with a molar concentration of 8-9 mol / L (specifically 8 mol / L in this example) as a complexing agent; Sodium persulfate with a molar concentration of 1.25–1.68 mol / L (specifically 1.61 mol / L in this example) was prepared as an oxidant; 2. Add 150-250L (approximately 200L in this example) of pure water to the reactor, add a precipitant to adjust the pH to 12.5±0.1, add a complexing agent, start stirring, and stir at a speed of 400±5 rpm to raise the reactor temperature to 45-55℃ (approximately 50℃ in this example). 3. Inject the precipitant into the reactor at a flow rate of 0.2–0.6 L / min (0.5 L / min in this embodiment); inject the oxidant into the reactor at a flow rate of 0.20–0.99 L / min (0.23 L / min in this embodiment); inject the complexing agent into the reactor at a flow rate of 0.01–0.03 L / min (0.01 L / min in this embodiment); inject the cobalt salt solution into the reactor at a flow rate of 0.55–1.65 L / min (1 L / min in this embodiment); during this process, adjust the flow rate of the precipitant to ensure that the pH in the reactor is ≥12.5. 4. When the liquid level in the reactor reaches 700-800L (750L in this embodiment), turn on the discharge pump to transfer the material to the transfer tank; 5. Start cleaning the material when the liquid level in the intermediate transfer tank reaches 50%; 6. When cleaning materials, turn on the feed pump, open the reflux valve, and turn on the reflux pump. The purpose of this step is to wait for the material to form a filter cake layer on the filter cloth to effectively reduce material loss. When the discharged mother liquor is clear and contains very little material, spin dry, and then pass in 75-85℃ hot pure water to wash away S and Na impurities in the material. 7. The cleaned and qualified materials are dried in an oven at a temperature of 150-160℃ (150℃ in this example) until the moisture content is <1.5%. At this time, the material is pure cobalt hydroxyl oxide. If the drying temperature is adjusted to 220-230℃ (220℃ in this example), the material is pure cobalt tetroxide. 8. The dried material is coarsely crushed using a roller mill. The particle size D50 of the crushed material is 1.5~3.5μm. 9. The coarsely crushed material is then finely crushed using an air jet mill. The particle size of the crushed material is D50: 0.01-0.5μm, Dmax≤5μm. 10. The finely pulverized material is demagnetized, and the magnetic content is ≤70ppb; 11. Pack the demagnetized materials.

[0048] Example 3: Selection of Oxidizing Agent, Complexing Agent, and Material Drying Temperature This embodiment has screened the reagents and method parameters in Example 2, as detailed below: 1. Screening of oxidant type and flow rate: Using the scheme in Example 2, hydrogen peroxide (30%), ammonium persulfate (400 g / L), and sodium persulfate (400 g / L) were used as oxidants for detection.

[0049] (1) Hydrogen peroxide (30%) Experimental method: The only difference from Example 2 is that hydrogen peroxide (30%) was used as the oxidant, the reactor temperature (synthesis temperature) was set to 35, 45, 50 and 60℃ respectively, and the flow rate of the oxidant was set to 0.077 and 0.154 L / min respectively. The synthesized phase and the specific surface area of ​​the phase were detected.

[0050] Table 1

[0051] The test results are shown in Table 1. As can be seen from the table, hydrogen peroxide can act as an oxidant to oxidize divalent cobalt hydroxide to trivalent cobalt hydroxyl oxide. When hydrogen peroxide is added in excess by 2 times to oxidize cobalt hydroxide to cobalt hydroxyl oxide, its BET does not increase significantly. At the same time, the reaction temperature has little effect on the BET of cobalt hydroxyl oxide. When the temperature is low (35℃), the reactivity of hydrogen peroxide is low, resulting in a lower BET of cobalt hydroxyl oxide. When the temperature is too high (60℃), hydrogen peroxide partially decomposes, reducing its oxidizing ability and resulting in a lower BET of cobalt hydroxyl oxide.

[0052] 2. Ammonium persulfate (400g / L) Experimental method: The only difference from Example 2 is that ammonium persulfate (400 g / L) was used as the oxidant, the reactor temperature (synthesis temperature) was set to 50°C, and the flow rate of the oxidant was set to 0.213 L / min and 0.35 L / min, respectively. The synthesized phase and the specific surface area of ​​the phase were detected.

[0053] Table 2

[0054] The test results are shown in Table 2 and Figure 1-2 As shown, ammonium persulfate, as an oxidant, can oxidize divalent cobalt hydroxide to trivalent cobalt hydroxyl oxide. The BET of cobalt hydroxyl oxide oxidized using ammonium persulfate is higher, possibly because the standard electrode potential of ammonium persulfate is 2.01V, while that of hydrogen peroxide is 1.77V, thus ammonium persulfate has a stronger oxidizing ability than hydrogen peroxide. However, the BET of cobalt hydroxyl oxide oxidized with an excess of 1.65 times ammonium persulfate is lower. This is because ammonium persulfate itself releases NH4+ under strongly alkaline conditions. + With OH - The trivalent cobalt hydroxide combines with ammonia to form a complex and dissolve in a strongly alkaline environment, resulting in material loss. The incompletely dissolved trivalent cobalt hydroxide is very dense, causing a lower BET.

[0055] 3. Sodium persulfate (400g / L) Experimental method: The only difference from Example 2 is that sodium persulfate (400 g / L) was used as the oxidant, the reactor temperature (synthesis temperature) was set to 50°C, and the flow rate of the oxidant was set to 0.23 and 0.35 L / min, respectively. The synthesized phase and the specific surface area of ​​the phase were detected.

[0056] Table 3

[0057] The test results are shown in Table 3 and Figure 3-6 As shown, sodium persulfate can act as an oxidant to oxidize divalent cobalt hydroxide to trivalent cobalt hydroxide. The cobalt hydroxide BET oxidized by sodium persulfate in excess of 1.5 times is equivalent to that oxidized by sodium persulfate in normal amounts, indicating that sodium persulfate does not need to be in excess to meet the requirements.

[0058] In summary, sodium persulfate has a stronger oxidizing power than ammonium persulfate and hydrogen peroxide. Therefore, sodium persulfate was chosen as the oxidant for subsequent experiments.

[0059] 2. Screening of complexing agent dosage and flow rate Experimental method: The only difference from Example 2 is that ammonia (NH3·H2O) was used as the complexing agent, the reactor temperature (synthesis temperature) was set to 50℃, and the flow rate of ammonia was set to 0, 0.0058, 0.01, 0.012, and 0.047 L / min, respectively. The synthesized phase and the specific surface area of ​​the phase were detected.

[0060] Table 4

[0061] The test results are shown in Table 4 and Figure 7-11 As shown, a higher ammonia flow rate during synthesis results in higher crystallinity of cobalt hydroxyoxide, lower BET, and lower levels of impurities Na and S. Ammonia affects the crystallinity of cobalt hydroxyoxide, thus reducing the content of impurities Na and S. Conversely, the absence of ammonia during synthesis results in lower crystallinity, higher BET, and higher levels of impurities Na and S. Considering both product specifications and production costs, an ammonia flow rate of 0.01 L / min is more suitable. Therefore, an ammonia flow rate of 0.01 L / min was selected for subsequent experiments.

[0062] 3. Screening of separation methods Since cobalt hydroxyoxide has nanoscale particles (D50 < 3.5 μm) during synthesis, the small particle size leads to significant material percolation during solid-liquid separation. This percolation is caused by insufficient filter cake thickness. Therefore, a material recycling method is employed to form a thicker filter cake, thus addressing the percolation issue and improving the yield. This embodiment compares the effects of conventional solid-liquid separation and recycling methods on the recovery rate of cobalt hydroxyoxide using the method described in Example 2. Figure 12 This is a flowchart of a conventional solid-liquid separation process. Figure 13 The flowchart shows the process of using a cyclic reflux method (i.e., the separation method in Example 2).

[0063] The typical solid-liquid separation process is as follows: Step 1: Use a feeding pump to pump cobalt hydroxide from the transfer tank into the already opened release machine; Step 2: While feeding, solid-liquid separation is carried out. Some material will penetrate the filter cloth with the filtrate, resulting in material loss. Step 3: After the material has been dried by the centrifuge, use hot water at 75-85℃ to clean the impurities inside the material. Step 4: Dry the material again; Step 5: Unload and prepare for drying.

[0064] The specific process using the cyclic reflow method is as follows: Step 1: Use a feeding pump to pump cobalt hydroxide from the transfer tank into the already opened release machine; Step 2: Close the reflux valve and start the circulation pump; Step 3: While feeding, solid-liquid separation is carried out. The material that penetrates the filter cloth is circulated to the transfer tank. The repeated circulation makes the material form a thicker filter cake layer, thereby reducing the material permeation. Step 4: After the material has been dried by the centrifuge, open the reflux valve, turn off the circulation pump, and use 75-85℃ hot water to clean the impurities inside the material. Step 5: Dry the material again; Step 6: Unload and prepare for drying.

[0065] The yield comparison results of different separation methods are shown in Table 5. It can be seen from the table that the yield of the reflux method is significantly higher.

[0066] Table 5

[0067] 4. Material drying temperature screening Experimental method: The only difference from Example 2 is the drying temperature. Drying was carried out at 150℃, 180℃, 200℃ and 220℃. The synthesized phase and the specific surface area of ​​the phase were measured.

[0068] Table 6

[0069] The results are shown in Table 6 and Figure 14-17 As shown, the drying temperature at 220℃ transforms the material into cobalt tetroxide; therefore, the drying temperature for preparing cobalt hydroxyl oxide cannot exceed 200℃. Furthermore, from... Figure 14-17 As can be seen from the results, the cobalt hydroxyl oxide and cobalt tetroxide prepared by the method of the present invention have high purity and no impurity peaks.

[0070] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method for the continuous and efficient preparation of nano-sized cobalt hydroxyl oxide and cobalt tetroxide, characterized in that, The method includes the following steps: (1) Add cobalt salt solution, oxidant and precipitant to complexing agent and solvent, stir to react and obtain reactants; (2) The reactants are dried at 150-160°C to obtain cobalt hydroxyl oxide; the reactants are dried at 220-230°C to obtain cobalt tetroxide.

2. The method according to claim 1, characterized in that, The cobalt salt solution includes one or more of cobalt chloride aqueous solution, cobalt sulfate aqueous solution, and cobalt nitrate aqueous solution; Preferably, the concentration of the cobalt salt solution is 1.3-1.7 mol / L.

3. The method according to claim 1, characterized in that, The complexing agent includes one or more of ammonia, potassium hydroxide aqueous solution, sodium hydroxide aqueous solution, and lithium hydroxide aqueous solution; Preferably, the concentration of the complexing agent is 8-9 mol / L.

4. The method according to claim 1, characterized in that, The oxidant includes one or more of hydrogen peroxide, ammonium persulfate, sodium hypochlorite, sodium perchlorate, sodium persulfate, sodium peroxide, and ozone; Preferably, the oxidant is sodium persulfate; More preferably, the concentration of the oxidant is 8-9 mol / L.

5. The method according to claim 1, characterized in that, The precipitant includes potassium hydroxide and sodium hydroxide.

6. The method according to claim 1, characterized in that, The molar mass ratio of the cobalt salt to the oxidant is (1-4):1; And / or, the molar mass ratio of the cobalt salt to the complexing agent is (1-10):

1.

7. The method according to claim 1, characterized in that, The temperature of the stirring reaction is 45-55℃; And / or, the pH of the stirring reaction is >12.

5.

8. A cobalt hydroxyl oxide, characterized in that, Prepared by the method described in any one of claims 1-7.

9. A cobalt tetroxide, characterized in that, Prepared by the method described in any one of claims 1-7.

10. The use of the method according to any one of claims 1-7 in the preparation of cobalt hydroxyoxide and / or cobalt tetroxide.

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