Method for calculating specific surface area of nanometer cobalt hydroxide

Abstract

The application provides a method for calculating the specific surface area of nanometer cobalt hydroxide, and belongs to the technical field of lithium ion battery material preparation, and solves the problem of difficult accurate adjustment of the specific surface area of nanometer cobalt hydroxide, wherein the application uses cobalt sulfate as raw material to prepare solution A and solution B; the prepared solution is subjected to nanometer cobalt hydroxide synthesis reaction; then the synthesized slurry is aged, washed, dried and airflow broken to obtain nanometer cobalt hydroxide product; the concentration of sodium hydroxide, the synthesis temperature range, the specific surface area of the prepared nanometer cobalt hydroxide, the negative linear relationship and the numerical relationship between the concentration of the sodium hydroxide solution, the synthesis temperature and the specific surface area of the nanometer cobalt hydroxide are set. By adjusting the concentration of the sodium hydroxide solution and the synthesis temperature during the wet synthesis of nanometer cobalt hydroxide, the specific surface area of the nanometer cobalt hydroxide can be accurately adjusted within a range, and the control precision reaches the theoretical requirement.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery material preparation technology, specifically relating to a method for calculating the specific surface area of ​​nano-cobalt hydroxide. Background Technology

[0002] Lithium cobalt oxide is the earliest commercially available cathode material for lithium-ion batteries. It has advantages such as high operating voltage, stable discharge, high specific energy, and good cycle performance. It is mainly used to manufacture cathode materials for lithium-ion batteries in mobile phones, laptops, and other portable electronic devices.

[0003] Currently, high-voltage lithium cobalt oxide cathode materials are typically prepared using a lithium-to-cobalt ratio of 1.05-1.1:1 to compensate for lithium loss during sintering. However, this results in residual Li₂O on the surface of the cathode material. This residual Li₂O readily reacts with H₂O and CO₂ to form Li₂CO₃ / LiOH, which adheres to the cathode material surface. During charge and discharge, Li₂CO₃ / LiOH reacts with the electrolyte to generate CO₂, causing internal expansion and potentially explosion. Related research has found that coating the cathode material with a layer of nano-cobalt hydroxide during lithium cobalt oxide sintering not only effectively reduces residual lithium but also forms a cobalt-rich concentration gradient layer on the cathode material surface, thereby improving the material's cycle performance. Therefore, sheet-like nano-cobalt hydroxide is the optimal choice for preparing high-voltage lithium cobalt oxide cathode materials.

[0004] Specific surface area refers to the total surface area per unit mass of a substance, and it is one of the important parameters affecting the performance of cathode materials. Cobalt hydroxide (Co(OH)₂), as a precursor material for the synthesis of lithium cobalt oxide (LiCoO₂), has a significant impact on the performance of the final lithium cobalt oxide due to its specific surface area. Firstly, a larger specific surface area of ​​cobalt hydroxide means more surface active sites and a larger contact area with the lithium source, thus facilitating a more uniform and faster synthesis of lithium cobalt oxide. However, a larger specific surface area increases the difficulty of oxidation prevention and washing / drying during the preparation of cobalt hydroxide. Therefore, when developing new products, it is necessary to comprehensively consider specific surface area and other factors to find the optimal balance. Consequently, finding a method for calculating the specific surface area of ​​nano-cobalt hydroxide is particularly important. However, a literature review shows that there are currently no relevant studies available. Summary of the Invention

[0005] The purpose of this invention is to provide a method for calculating the specific surface area of ​​nano-cobalt hydroxide, so as to solve the problem that the specific surface area of ​​nano-cobalt hydroxide is difficult to adjust accurately.

[0006] The technical solution of this invention is: a method for calculating the specific surface area of ​​nano-cobalt hydroxide, comprising the following steps: Step 1: Using cobalt sulfate as raw material, prepare a cobalt solution with a cobalt concentration of 90-110 g / L as solution A, and prepare a mixed solution of sodium hydroxide and hydrazine hydrate as solution B; Step 2: Add solution B, which is prepared to account for 40% of the volume of the reaction vessel, to the reaction vessel, and then add solution A to the reaction vessel. The nano-cobalt hydroxide synthesis reaction is carried out under stirring conditions. Step 3: When the pH value of the synthesized slurry in the reactor drops to 12.0-12.1, stop adding liquid. Then, age, wash, dry, and air-jet break the synthesized slurry to obtain nano cobalt hydroxide product. Step 4: Define the concentration range of sodium hydroxide prepared in Step 1 as x, where x ranges from 50 to 300 g / L. Define the specific surface area of ​​the nano-cobalt hydroxide prepared in Step 3 as y, where y ranges from 20 to 30 m². 2 / g, a negative linear relationship is set between the sodium hydroxide solution concentration x and the specific surface area y of nano cobalt hydroxide, with the numerical relationship being y=-0.04x+32; Let the synthesis temperature in step two be t, ranging from 30 to 70℃, and let the specific surface area of ​​the nano-cobalt hydroxide prepared in step three be y, ranging from 10 to 20 m². 2 / g, the synthesis temperature t is set to have a negative linear relationship with the specific surface area y of nano cobalt hydroxide, and the numerical relationship is y=-0.25t+27.5.

[0007] As a further improvement of the present invention, in step two, the flow rate of solution A is strictly controlled to be 50-60% of the volume of the reactor per hour, the reaction temperature is 20±1℃, and the stirring intensity is 50Hz.

[0008] As a further improvement of the present invention, in step three, the other physicochemical properties of the obtained nano-cobalt hydroxide product are at the nanoscale, and the microstructure is lamellar.

[0009] As a further improvement of the present invention, in step four, the specific surface area y of nano-cobalt hydroxide calculated according to the equation y=-0.04x+32 has an error compared with the actual experimentally prepared specific surface area y* of nano-cobalt hydroxide, with an error range of ±0.5m. 2 / g, that is, |y*-y|≤0.5m 2 / g.

[0010] As a further improvement of the present invention, in step four, the specific surface area y of nano-cobalt hydroxide calculated according to the equation y=-0.25t+27.5 has an error range of ±1.0m compared with the specific surface area y* of nano-cobalt hydroxide actually prepared in the experiment. 2 / g, that is, |y*-y|≤1.0m 2 / g.

[0011] The beneficial effects of this invention are as follows: The precise setting of raw material and solution preparation in this invention lays a solid foundation for establishing a negative linear relationship. This invention fixes cobalt sulfate as the sole raw material, limiting the cobalt concentration in solution A to 90-110 g / L. Solution B uses a mixture of sodium hydroxide and hydrazine hydrate, occupying 40% of the reactor volume. This setting eliminates interference from raw material substitution, concentration imbalance, or fluctuations in system component ratios on the reaction mechanism, making sodium hydroxide concentration and synthesis temperature the core controllable variables affecting specific surface area. This provides a prerequisite for the stable establishment of the two subsequent negative linear relationships, ensuring the purity of the variable influence.

[0012] This invention employs synergistic control of multiple reaction process parameters to ensure the stable effectiveness of the negative linear relationship. By strictly controlling the flow rate of liquid A, reaction temperature, stirring intensity, and termination pH, this invention eliminates irrelevant interference factors such as uneven local reaction rates and system environmental fluctuations. This ensures that the effects of sodium hydroxide concentration and synthesis temperature on the relative surface area exhibit a purely linear correlation, avoiding relationship deviations caused by uncontrolled process parameters. This guarantees that the two relationships, y = -0.04x + 32 and y = -0.25t + 27.5, remain valid within the industrial-scale parameter range.

[0013] This invention quantifies the negative linear relationship, enabling precise prediction and reverse control of specific surface area, breaking through the bottlenecks of traditional processes. This invention clearly establishes a negative linear correlation between sodium hydroxide concentration, synthesis temperature, and specific surface area. The required process parameters can be directly deduced from the target specific surface area, replacing the traditional blind experimentation method and significantly improving R&D and production efficiency. Simultaneously, the errors of the two relationships are controlled within ±0.5 μm. 2 / g, ±1.0m 2 Within / g, ensuring precise control, it not only meets the structural and activity requirements for high-voltage lithium cobalt oxide coating, but also balances the difficulties of anti-oxidation, washing and drying in the preparation process of cobalt hydroxide, achieving synergistic optimization of performance and process.

[0014] This invention provides the industry with a method for precisely controlling the specific surface area of ​​nano-cobalt hydroxide. In the process of developing nano-cobalt hydroxide products, the inventors discovered and confirmed that there is a negative linear relationship between the concentration of sodium hydroxide solution, the synthesis temperature and the specific surface area of ​​nano-cobalt hydroxide. Based on the experimental results, specific formulas for the relationship between the specific surface area of ​​nano-cobalt hydroxide and the concentration of sodium hydroxide and the synthesis temperature were obtained, and the error range meets the theoretical requirements. Attached Figure Description

[0015] Figure 1 The image shows the microstructure of the nano-cobalt hydroxide prepared in Example 1 at 10,000x magnification, under the condition that there is a negative linear relationship between the concentration of sodium hydroxide solution and the specific surface area of ​​nano-cobalt hydroxide. Figure 2The image shows the microstructure of the nano-cobalt hydroxide prepared in Example 1 at 30,000x magnification, under the condition that there is a negative linear relationship between the concentration of sodium hydroxide solution and the specific surface area of ​​nano-cobalt hydroxide. Figure 3 The image shows the microstructure of the nano-cobalt hydroxide prepared in Example 1 at 10,000x magnification, under conditions where there is a negative linear relationship between the synthesis temperature and the specific surface area of ​​the nano-cobalt hydroxide. Figure 4 The image shows the microstructure of the nano-cobalt hydroxide prepared in Example 1 at 30,000x magnification, under conditions where there is a negative linear relationship between the synthesis temperature and the specific surface area of ​​the nano-cobalt hydroxide. Figure 5 The image shows the microstructure of the nano-cobalt hydroxide prepared in Example 2 at 10,000x magnification, under the condition that there is a negative linear relationship between the concentration of sodium hydroxide solution and the specific surface area of ​​nano-cobalt hydroxide. Figure 6 The image shows the microstructure of the nano-cobalt hydroxide prepared in Example 2 at 30,000x magnification, under the condition that there is a negative linear relationship between the concentration of sodium hydroxide solution and the specific surface area of ​​nano-cobalt hydroxide. Figure 7 The image shows the microstructure of the nano-cobalt hydroxide prepared in Example 2 at 10,000x magnification, under conditions where there is a negative linear relationship between the synthesis temperature and the specific surface area of ​​the nano-cobalt hydroxide. Figure 8 The image shows the microstructure of the nano-cobalt hydroxide prepared in Example 2 at 30,000x magnification, under the condition that there is a negative linear relationship between the synthesis temperature and the specific surface area of ​​the nano-cobalt hydroxide. Figure 9 The image shows the microstructure of the nano-cobalt hydroxide prepared in Example 3 at 10,000x magnification, under the condition that there is a negative linear relationship between the concentration of sodium hydroxide solution and the specific surface area of ​​nano-cobalt hydroxide. Figure 10 The image shows the microstructure of the nano-cobalt hydroxide prepared in Example 3 at 30,000x magnification, under the condition that there is a negative linear relationship between the concentration of sodium hydroxide solution and the specific surface area of ​​nano-cobalt hydroxide. Figure 11 The image shows the microstructure of the nano-cobalt hydroxide prepared in Example 3 at 10,000x magnification, under conditions where there is a negative linear relationship between the synthesis temperature and the specific surface area of ​​the nano-cobalt hydroxide. Figure 12 The image shows the microstructure of the nano-cobalt hydroxide prepared in Example 3 at magnification of 30,000, under conditions where there is a negative linear relationship between the synthesis temperature and the specific surface area of ​​the nano-cobalt hydroxide. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Example 1 Step 1: Using cobalt sulfate as raw material, prepare a cobalt solution with a cobalt concentration of 100 g / L as solution A, and prepare a mixed solution of sodium hydroxide and hydrazine hydrate as solution B.

[0018] Step 2: Add solution B, which is prepared to account for 40% of the volume of the reactor, to the reactor. Then add solution A to the reactor and carry out the nano-cobalt hydroxide synthesis reaction under stirring conditions. During the reaction, strictly control the flow rate of solution A to 55% of the reactor volume per hour, the reaction temperature to 21℃, and the stirring intensity to 50Hz.

[0019] Step 3: When the pH value of the synthesized slurry in the reactor drops to 12.0, stop adding liquid. Then, age, wash, dry, and air-jet break the synthesized slurry to obtain nano cobalt hydroxide product. The other physicochemical properties of the obtained nano cobalt hydroxide product are nanoscale, and the microstructure is lamellar.

[0020] Step 4: Define the concentration range of sodium hydroxide prepared in Step 1 as x, where x ranges from 50 to 300 g / L. Define the specific surface area of ​​the nano-cobalt hydroxide prepared in Step 3 as y, where y ranges from 20 to 30 m². 2 / g, a negative linear relationship is set between the sodium hydroxide solution concentration x and the specific surface area y of nano cobalt hydroxide, with the numerical relationship being y=-0.04x+32; The specific surface area y of nano-cobalt hydroxide calculated using the equation y = -0.04x + 32 differs from the actual experimentally prepared specific surface area y* of nano-cobalt hydroxide by an error range of ±0.5m. 2 / g, that is, |y*-y|≤0.5m 2 / g.

[0021] The specific surface area of ​​nano-cobalt hydroxide was measured to be 27.67 m². 2 / g, calculated according to y=-0.04x+32, the theoretical specific surface area of ​​nano-cobalt hydroxide is y=28m². 2 / g, error |y*-y|=|27.67-28|=0.33m 2 / g≤0.5m 2 / g.

[0022] The microstructure of the prepared nano-cobalt hydroxide is shown in the figure. Figures 1-2 .

[0023] Step 1: Using cobalt sulfate as raw material, prepare a cobalt solution with a cobalt concentration of 100 g / L as solution A, and prepare a mixed solution of sodium hydroxide and hydrazine hydrate as solution B.

[0024] Step 2: Add solution B, which is prepared to account for 40% of the volume of the reactor, to the reactor. Then add solution A to the reactor and carry out the nano-cobalt hydroxide synthesis reaction under stirring conditions. During the reaction, strictly control the flow rate of solution A to 55% of the reactor volume per hour, the reaction temperature to 21℃, and the stirring intensity to 50Hz.

[0025] Step 3: When the pH value of the synthesized slurry in the reactor drops to 12.0, stop adding liquid. Then, age, wash, dry, and air-jet break the synthesized slurry to obtain nano cobalt hydroxide product. The other physicochemical properties of the obtained nano cobalt hydroxide product are nanoscale, and the microstructure is lamellar.

[0026] Step 4: Set the synthesis temperature of the synthesis process in Step 2 as t, with a range of 30-70℃. Set the specific surface area of ​​the nano-cobalt hydroxide prepared in Step 3 as y, with a range of 10-20m². 2 / g, the synthesis temperature t is set to have a negative linear relationship with the specific surface area y of nano cobalt hydroxide, and the numerical relationship is y=-0.25t+27.5.

[0027] The specific surface area y of nano-cobalt hydroxide calculated using the equation y = -0.25t + 27.5 differs from the actual experimentally prepared specific surface area y* of nano-cobalt hydroxide by an error range of ±1.0 m. 2 / g, that is, |y*-y|≤1.0m 2 / g.

[0028] The specific surface area of ​​nano-cobalt hydroxide was measured to be 20.41 m². 2 / g, calculated according to y=-0.25t+27.5, the theoretical specific surface area of ​​nano-cobalt hydroxide is y=20m². 2 / g, error |y*-y|=|20.41-20|=0.41m 2 / g≤1.0m 2 / g.

[0029] The microstructure of the prepared nano-cobalt hydroxide is shown in the figure. Figures 3-4 .

[0030] Example 2 Step 1: Using cobalt sulfate as raw material, prepare a cobalt solution with a cobalt concentration of 110 g / L as solution A, and prepare a mixed solution of sodium hydroxide and hydrazine hydrate as solution B.

[0031] Step 2: Add solution B, which is prepared to account for 40% of the volume of the reaction vessel, to the reaction vessel. Then add solution A to the reaction vessel and carry out the nano-cobalt hydroxide synthesis reaction under stirring conditions. During the reaction, strictly control the flow rate of solution A to 60% of the reaction vessel volume per hour, the reaction temperature to 21℃, and the stirring intensity to 50Hz.

[0032] Step 3: When the pH value of the synthesized slurry in the reactor drops to 12.1, stop adding liquid. Then, age, wash, dry, and air-jet break the synthesized slurry to obtain nano-cobalt hydroxide product. Other physicochemical properties of the obtained nano-cobalt hydroxide product are nanoscale, and the microstructure is lamellar.

[0033] Step 4: Define the concentration range of sodium hydroxide prepared in Step 1 as x, where x ranges from 50 to 300 g / L. Define the specific surface area of ​​the nano-cobalt hydroxide prepared in Step 3 as y, where y ranges from 20 to 30 m². 2 / g, a negative linear relationship is set between the sodium hydroxide solution concentration x and the specific surface area y of nano cobalt hydroxide, with the numerical relationship being y=-0.04x+32; The specific surface area y of nano-cobalt hydroxide calculated using the equation y = -0.04x + 32 differs from the actual experimentally prepared specific surface area y* of nano-cobalt hydroxide by an error range of ±0.5m. 2 / g, that is, |y*-y|≤0.5m 2 / g.

[0034] The specific surface area of ​​nano-cobalt hydroxide was measured to be 25.70 m². 2 / g, calculated according to y=-0.04x+32, the theoretical specific surface area of ​​nano-cobalt hydroxide is y=26m². 2 / g, error |y*-y|=|25.70-26|=0.30m 2 / g≤0.5m 2 / g.

[0035] The microstructure of the prepared nano-cobalt hydroxide is shown in the figure. Figures 5-6 .

[0036] Step 1: Using cobalt sulfate as raw material, prepare a cobalt solution with a cobalt concentration of 110 g / L as solution A, and prepare a mixed solution of sodium hydroxide and hydrazine hydrate as solution B.

[0037] Step 2: Add solution B, which is prepared to account for 40% of the volume of the reaction vessel, to the reaction vessel. Then add solution A to the reaction vessel and carry out the nano-cobalt hydroxide synthesis reaction under stirring conditions. During the reaction, strictly control the flow rate of solution A to 60% of the reaction vessel volume per hour, the reaction temperature to 21℃, and the stirring intensity to 50Hz.

[0038] Step 3: When the pH value of the synthesized slurry in the reactor drops to 12.1, stop adding liquid. Then, age, wash, dry, and air-jet break the synthesized slurry to obtain nano-cobalt hydroxide product. Other physicochemical properties of the obtained nano-cobalt hydroxide product are nanoscale, and the microstructure is lamellar.

[0039] Step 4: Set the synthesis temperature of the synthesis process in Step 2 as t, with a range of 30-70℃. Set the specific surface area of ​​the nano-cobalt hydroxide prepared in Step 3 as y, with a range of 10-20m². 2 / g, the synthesis temperature t is set to have a negative linear relationship with the specific surface area y of nano cobalt hydroxide, and the numerical relationship is y=-0.25t+27.5.

[0040] The specific surface area y of nano-cobalt hydroxide calculated using the equation y = -0.25t + 27.5 differs from the actual experimentally prepared specific surface area y* of nano-cobalt hydroxide by an error range of ±1.0 m. 2 / g, that is, |y*-y|≤1.0m 2 / g.

[0041] The specific surface area of ​​nano-cobalt hydroxide was measured to be 17.07 m². 2 / g, calculated according to y=-0.25t+27.5, the theoretical specific surface area of ​​nano-cobalt hydroxide is y=17.5m². 2 / g, error |y*-y|=|17.07-17.50|=0.43m 2 / g≤1.0m 2 / g.

[0042] The microstructure of the prepared nano-cobalt hydroxide is shown in the figure. Figures 7-8 .

[0043] Example 3 Step 1: Using cobalt sulfate as raw material, prepare a cobalt solution with a cobalt concentration of 90 g / L as solution A, and prepare a mixed solution of sodium hydroxide and hydrazine hydrate as solution B.

[0044] Step 2: Add solution B, which is prepared to account for 40% of the volume of the reaction vessel, to the reaction vessel. Then add solution A to the reaction vessel and carry out the nano-cobalt hydroxide synthesis reaction under stirring conditions. During the reaction, strictly control the flow rate of solution A to 50% of the reaction vessel volume per hour, the reaction temperature to 19℃, and the stirring intensity to 50Hz.

[0045] Step 3: When the pH value of the synthesized slurry in the reactor drops to 12.1, stop adding liquid. Then, age, wash, dry, and air-jet break the synthesized slurry to obtain nano-cobalt hydroxide product. Other physicochemical properties of the obtained nano-cobalt hydroxide product are nanoscale, and the microstructure is lamellar.

[0046] Step 4: Define the concentration range of sodium hydroxide prepared in Step 1 as x, where x ranges from 50 to 300 g / L. Define the specific surface area of ​​the nano-cobalt hydroxide prepared in Step 3 as y, where y ranges from 20 to 30 m². 2 / g, a negative linear relationship is set between the sodium hydroxide solution concentration x and the specific surface area y of nano cobalt hydroxide, with the numerical relationship being y=-0.04x+32; The specific surface area y of nano-cobalt hydroxide calculated using the equation y = -0.04x + 32 differs from the actual experimentally prepared specific surface area y* of nano-cobalt hydroxide by an error range of ±0.5m. 2 / g, that is, |y*-y|≤0.5m 2 / g.

[0047] The specific surface area of ​​nano-cobalt hydroxide was measured to be 22.16 m². 2 / g, calculated according to y=-0.04x+32, the theoretical specific surface area of ​​nano-cobalt hydroxide is y=22m². 2 / g, error |y*-y|=|22.16-22|=0.16m 2 / g≤0.5m 2 / g.

[0048] The microstructure of the prepared nano-cobalt hydroxide is shown in the figure. Figures 9-10 .

[0049] Step 1: Using cobalt sulfate as raw material, prepare a cobalt solution with a cobalt concentration of 90 g / L as solution A, and prepare a mixed solution of sodium hydroxide and hydrazine hydrate as solution B.

[0050] Step 2: Add solution B, which is prepared to account for 40% of the volume of the reaction vessel, to the reaction vessel. Then add solution A to the reaction vessel and carry out the nano-cobalt hydroxide synthesis reaction under stirring conditions. During the reaction, strictly control the flow rate of solution A to 50% of the reaction vessel volume per hour, the reaction temperature to 19℃, and the stirring intensity to 50Hz.

[0051] Step 3: When the pH value of the synthesized slurry in the reactor drops to 12.1, stop adding liquid. Then, age, wash, dry, and air-jet break the synthesized slurry to obtain nano-cobalt hydroxide product. Other physicochemical properties of the obtained nano-cobalt hydroxide product are nanoscale, and the microstructure is lamellar.

[0052] Step 4: Set the synthesis temperature of the synthesis process in Step 2 as t, with a range of 30-70℃. Set the specific surface area of ​​the nano-cobalt hydroxide prepared in Step 3 as y, with a range of 10-20m². 2 / g, the synthesis temperature t is set to have a negative linear relationship with the specific surface area y of nano cobalt hydroxide, and the numerical relationship is y=-0.25t+27.5.

[0053] The specific surface area y of nano-cobalt hydroxide calculated using the equation y = -0.25t + 27.5 differs from the actual experimentally prepared specific surface area y* of nano-cobalt hydroxide by an error range of ±1.0 m. 2 / g, that is, |y*-y|≤1.0m 2 / g.

[0054] The specific surface area of ​​nano-cobalt hydroxide was measured to be 10.71 m². 2 / g, calculated according to y=-0.25t+27.5, the theoretical specific surface area of ​​nano-cobalt hydroxide is y=10m². 2 / g, error |y*-y|=|10.71-10|=0.71m 2 / g≤1.0m 2 / g.

[0055] The microstructure of the prepared nano-cobalt hydroxide is shown in the figure. Figures 11-12 .

[0056] Examples 1-3 were conducted under different process combinations with cobalt concentrations of 90-110 g / L, flow rates of solution A of 50-60% / h, and reaction temperatures of 19-21℃. The results showed that the error between the theoretical specific surface area calculated based on y=-0.04x+32 and the actual measured value was 0.16-0.33 m². 2 / g, the error calculated based on y=-0.25t+27.5 is 0.41-0.71m. 2 / g, none of which exceeded the limit; combined with Figures 1-12 As can be seen from the scanning electron microscope images, all products exhibit a uniform layered nanostructure, and their physicochemical properties meet the design requirements. In summary, the negative linear relationship between sodium hydroxide concentration, synthesis temperature, and specific surface area established in this invention is stable and reliable, and it forms an effective synergy with process parameters such as solution preparation and reaction control, achieving precise control of the specific surface area of ​​nano-cobalt hydroxide. The process is stable and controllable, and is fully applicable to industrial production scenarios.

Claims

1. A method for calculating the specific surface area of ​​nano-cobalt hydroxide, characterized in that: Includes the following steps: Step 1: Using cobalt sulfate as raw material, prepare a cobalt solution with a cobalt concentration of 90-110 g / L as solution A, and prepare a mixed solution of sodium hydroxide and hydrazine hydrate as solution B; Step 2: Add solution B, which is prepared to account for 40% of the volume of the reaction vessel, to the reaction vessel, and then add solution A to the reaction vessel. The nano-cobalt hydroxide synthesis reaction is carried out under stirring conditions. Step 3: When the pH value of the synthesized slurry in the reactor drops to 12.0-12.1, stop adding liquid. Then, age, wash, dry, and air-jet break the synthesized slurry to obtain nano cobalt hydroxide product. Step 4: Define the concentration range of sodium hydroxide prepared in Step 1 as x, where x ranges from 50 to 300 g / L. Define the specific surface area of ​​the nano-cobalt hydroxide prepared in Step 3 as y, where y ranges from 20 to 30 m². 2 / g, a negative linear relationship is set between the sodium hydroxide solution concentration x and the specific surface area y of nano cobalt hydroxide, with the numerical relationship being y=-0.04x+32; Let the synthesis temperature in step two be t, ranging from 30 to 70℃, and let the specific surface area of ​​the nano-cobalt hydroxide prepared in step three be y, ranging from 10 to 20 m². 2 / g, the synthesis temperature t is set to have a negative linear relationship with the specific surface area y of nano cobalt hydroxide, and the numerical relationship is y=-0.25t+27.

5.

2. The method for calculating the specific surface area of ​​nano-cobalt hydroxide according to claim 1, characterized in that: In step two, the flow rate of solution A is strictly controlled to be 50-60% of the reactor volume per hour, the reaction temperature is 20±1℃, and the stirring intensity is 50Hz.

3. The method for calculating the specific surface area of ​​nano-cobalt hydroxide according to claim 1, characterized in that: In step three, the other physicochemical properties of the obtained nano-cobalt hydroxide product are at the nanoscale, and the microstructure is lamellar.

4. The method for calculating the specific surface area of ​​nano-cobalt hydroxide according to claim 1, characterized in that: In step four, the specific surface area y of nano-cobalt hydroxide calculated according to the equation y=-0.04x+32 differs from the actual experimentally prepared specific surface area y* of nano-cobalt hydroxide by an error range of ±0.5m. 2 / g, that is, |y*-y|≤0.5m 2 / g.

5. The method for calculating the specific surface area of ​​nano-cobalt hydroxide according to claim 1, characterized in that: In step four, the specific surface area y of nano-cobalt hydroxide calculated according to the equation y = -0.25t + 27.5 differs from the actual experimentally prepared specific surface area y* of nano-cobalt hydroxide by an error range of ±1.0m. 2 / g, that is, |y*-y|≤1.0m 2 / g.

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