Preparation process of ultrafine and highly dispersed cobalt oxide

Abstract

The present invention discloses a preparation process of ultrafine and highly dispersed cobalt oxide, belonging to the technical field of cobalt oxide preparation. The process includes the following steps: S1. Mix cobalt nitrate hexahydrate and deionized water, and stir for 15 - 20 min to obtain a cobalt nitrate solution; S2. Take the cobalt nitrate solution, add a dispersant, stir for 30 - 40 min, adjust the pH to 9.2 - 9.5, age at 5 - 10 °C for 24 h, perform centrifugal separation, take the solid phase and wash it to obtain material A; S3. Place material A in a 100 mL autoclave, add absolute ethanol and n-butanol, stir for 30 - 40 min, purge the autoclave with nitrogen to expel the air in the autoclave, seal it, pressurize, heat and stir for 30 - 40 min, discharge the fluid in the autoclave, and cool the solid phase material in the autoclave to obtain material B; S4. Place material B in a muffle furnace for calcination, grind it, and sieve it to obtain ultrafine cobalt oxide with high dispersibility.

Description

Technical Field

[0001] The present invention belongs to the technical field of cobalt oxide preparation, and particularly relates to a preparation process of ultrafine and highly dispersed cobalt oxide. Background Art

[0002] Cobalt oxide occupies an indispensable position in many fields such as lithium-ion batteries, glass, ceramics, cemented carbide, and electronic materials. As a raw material for preparing key products such as lithium cobaltate and electronic pastes, cobalt oxide has extremely low requirements for impurity content, and also has extremely high standards for physical properties such as morphology, particle size, and distribution. Lithium-ion batteries have attracted much attention in the market due to their many advantages such as high voltage, large energy density, long cycle life, and environmental friendliness.

[0003] In recent years, with the continuous surge in the demand for small portable power sources, new vitality has been injected into the development of the lithium-ion battery industry. The rapid development of this industry has further promoted the research and production of cobalt-based cathode materials such as lithium cobaltate, lithium nickel cobaltate, and lithium nickel cobalt manganate. Therefore, the demand for cobalt-based cathode materials for lithium-ion batteries has also shown a rapid growth trend. Among them, cobalt oxide has become the main raw material for preparing these cathode materials.

[0004] There are various methods for preparing cobalt oxide, including solid-phase method, gas-phase method, liquid-phase method (such as chemical precipitation method, solvothermal method, hydrothermal method, sol-gel method, microemulsion method, electrodeposition method, reduction oxidation method, etc.), and combined method (such as hard template method, soft template method, grafting / modification-thermal decomposition method, etc.). However, due to traditional cobalt oxide preparation techniques and subsequent high-temperature calcination treatment, problems such as severe particle agglomeration, poor dispersion, unstable crystal structure, and difficulty in controlling crystal grains and crystal forms often occur, which to a certain extent limits the wide application of cobalt oxide materials. Therefore, researching and developing new cobalt oxide preparation techniques and optimizing their physical and chemical properties are of great significance for promoting the development of lithium-ion batteries and their related industries. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation process of ultrafine and highly dispersed cobalt oxide, which is used to improve the dispersion of cobalt oxide during the preparation process and improve the product quality.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A preparation process of ultrafine and highly dispersed cobalt oxide includes the following steps:

[0008] S1. Take cobalt nitrate hexahydrate and deionized water and mix them, stir for 15 - 20 min to obtain a cobalt nitrate solution;

[0009] S2. Take the cobalt nitrate solution, add a dispersant, stir for 30 - 40 min, adjust the pH to 9.2 - 9.5, age at 5 - 10 °C for 24 h, perform centrifugal separation, take the solid phase for washing to obtain Material A;

[0010] S3. Take Material A and place it in a 100 mL autoclave, add anhydrous ethanol and n - butanol, stir for 30 - 40 min, purge the autoclave with nitrogen to expel the air inside the autoclave, seal it, apply pressure, heat and stir for 30 - 40 min, discharge the fluid inside the autoclave, and cool the solid phase material inside the autoclave to obtain Material B;

[0011] S4. Take Material B and calcine it in a muffle furnace, grind it, and sieve it to obtain the ultrafine highly dispersed cobalt oxide.

[0012] As a preferred technical solution of the present invention, in step S1, the concentration of the cobalt nitrate solution is 0.2 mol / L.

[0013] As a preferred technical solution of the present invention, in step S2, the dosage ratio of the cobalt nitrate solution to the dispersant is 10 - 12 mL: 2 - 3 g.

[0014] As a preferred technical solution of the present invention, in step S3, the mass ratio of Material A, anhydrous ethanol, and n - butanol is 8 - 10: 30: 20.

[0015] As a preferred technical solution of the present invention, in step S3, the pressure heating refers to a pressure of 6.9 - 7.2 MPa and a temperature of 260 - 280 °C.

[0016] As a preferred technical solution of the present invention, the preparation of the dispersant includes the following steps:

[0017] Take N - dodecyl succinic anhydride, L - tert - leucine, and acetone and mix them, perform ultrasonic dispersion for 25 - 35 min, add N,N - dimethyl - 4 - pyridineamine, stir at 35 - 45 °C for 3 - 4 h, add 2 - (2 - butoxyethoxy) ethanol, continue to stir for 1 - 2 h, and rotary evaporate to remove acetone to obtain the dispersant.

[0018] As a preferred technical solution of the present invention, the mass ratio of N - dodecyl succinic anhydride, L - tert - leucine, acetone, N,N - dimethyl - 4 - pyridineamine, and 2 - (2 - butoxyethoxy) ethanol is 10 - 12: 8 - 10: 50: 1 - 2: 10 - 12.

[0019] As a preferred technical solution of the present invention, in step S4, the calcination refers to heating at 5 - 8 °C / min to 400 - 500 °C and calcining for 3 - 5 h.

[0020] The beneficial effects of the present invention:

[0021] The preparation process of an ultrafine and highly dispersed cobalt oxide disclosed by the present invention reduces the surface tension during the preparation process of cobalt oxide by adding a dispersant, inhibits its agglomeration, increases its dispersibility, makes the prepared cobalt oxide have uniform size, and has good tap density. Specific Embodiments

[0022] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following, in combination with embodiments, details the specific embodiments, structures, features and their effects according to the present invention as follows.

[0023] Example 1

[0024] A preparation process of an ultrafine and highly dispersed cobalt oxide includes the following steps:

[0025] S1. Take cobalt nitrate hexahydrate and deionized water, mix them, and stir for 15 min to obtain a cobalt nitrate solution; the concentration of the cobalt nitrate solution is 0.2 mol / L;

[0026] S2. Take the cobalt nitrate solution, add a dispersant, stir for 30 min, adjust the pH to 9.2, age at 5°C for 24 h, perform centrifugal separation, take the solid phase for washing to obtain material A; the dosage ratio of the cobalt nitrate solution to the dispersant is 10 mL:2 g;

[0027] S3. Take material A and place it in a 100 mL autoclave, add absolute ethanol and n-butanol, stir for 30 min, purge the autoclave with nitrogen to remove the air in the autoclave, seal it, pressurize, heat and stir for 30 min, discharge the fluid in the autoclave, and cool the solid phase material in the autoclave to obtain material B; the mass ratio of material A, absolute ethanol and n-butanol is 8:30:20; the pressurized heating refers to a pressure of 6.9 MPa and a temperature of 260°C;

[0028] S4. Take material B and place it in a muffle furnace for calcination, grinding, and sieving to obtain the ultrafine and highly dispersed cobalt oxide; the calcination refers to heating to 400°C at a rate of 5°C / min and calcining for 3 h.

[0029] The preparation of the dispersant includes the following steps:

[0030] Take N-dodecyl succinic anhydride, L-tert-leucine, and acetone, ultrasonically disperse for 25 min, add N,N-dimethyl-4-pyridinamine, stir at 35°C for 3 h, add 2-(2-butoxyethoxy)ethanol, continue to stir for 1 h, and rotary evaporate to remove acetone to obtain the dispersant; the mass ratio of N-dodecyl succinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridinamine, and 2-(2-butoxyethoxy)ethanol is 10:8:50:1:10.

[0031] Example 2

[0032] A preparation process of ultrafine and highly dispersed cobalt oxide includes the following steps:

[0033] S1. Take cobalt nitrate hexahydrate and deionized water, mix them, and stir for 18 min to obtain a cobalt nitrate solution; the concentration of the cobalt nitrate solution is 0.2 mol / L.

[0034] S2. Take the cobalt nitrate solution, add a dispersant, stir for 35 min, adjust the pH to 9.3, age at 8°C for 24 h, perform centrifugal separation, take the solid phase for washing to obtain material A; the dosage ratio of the cobalt nitrate solution to the dispersant is 11 mL: 2.5 g.

[0035] S3. Take material A and place it in a 100 mL autoclave, add absolute ethanol and n-butanol, stir for 35 min, purge the autoclave with nitrogen to remove the air in the autoclave, seal it, pressurize, heat, and stir for 35 min, discharge the fluid in the autoclave, and cool the solid phase material in the autoclave to obtain material B; the mass ratio of material A, absolute ethanol, and n-butanol is 9: 30: 20; the pressurized heating means a pressure of 7.1 MPa and a temperature of 270°C.

[0036] S4. Take material B and place it in a muffle furnace for calcination, grinding, and sieving to obtain the ultrafine and highly dispersed cobalt oxide; the calcination means heating to 450°C at a rate of 6°C / min and calcining for 4 h.

[0037] The preparation of the dispersant includes the following steps:

[0038] Take N-dodecyl succinic anhydride, L-tert-leucine, and acetone, mix them, perform ultrasonic dispersion for 30 min, add N,N-dimethyl-4-pyridinamine, stir at 40°C for 3.5 h, add 2-(2-butoxyethoxy)ethanol, continue to stir for 1.5 h, and rotary evaporate to remove acetone to obtain the dispersant; the mass ratio of N-dodecyl succinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridinamine, and 2-(2-butoxyethoxy)ethanol is 11: 9: 50: 1.5: 11.

[0039] Example 3

[0040] A preparation process of ultrafine and highly dispersed cobalt oxide includes the following steps:

[0041] S1. Take cobalt nitrate hexahydrate and deionized water, mix them, and stir for 20 min to obtain a cobalt nitrate solution; the concentration of the cobalt nitrate solution is 0.2 mol / L.

[0042] S2. Take the cobalt nitrate solution, add a dispersant, stir for 40 min, adjust the pH to 9.5, age at 10 °C for 24 h, perform centrifugal separation, take the solid phase for washing to obtain Material A; the dosage ratio of the cobalt nitrate solution to the dispersant is 12 mL: 3 g;

[0043] S3. Take Material A and place it in a 100 mL autoclave, add absolute ethanol and n-butanol, stir for 40 min, purge the autoclave with nitrogen to remove the air in the autoclave, seal it, pressurize and heat while stirring for 40 min, drain the fluid in the autoclave, and cool the solid phase material in the autoclave to obtain Material B; the mass ratio of Material A, absolute ethanol, and n-butanol is 10: 30: 20; the pressurized heating refers to a pressure of 7.2 MPa and a temperature of 280 °C;

[0044] S4. Take Material B and calcine it in a muffle furnace, grind it, and sieve it to obtain the ultrafine highly dispersed cobalt oxide; the calcination refers to heating to 500 °C at a rate of 8 °C / min and calcining for 5 h.

[0045] The preparation of the dispersant includes the following steps:

[0046] Take N-dodecyl succinic anhydride, L-tert-leucine, and acetone, mix them, perform ultrasonic dispersion for 35 min, add N,N-dimethyl-4-pyridineamine, stir at 45 °C for 4 h, add 2-(2-butoxyethoxy)ethanol, continue stirring for 2 h, and rotary evaporate to remove acetone to obtain the dispersant; the mass ratio of N-dodecyl succinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridineamine, and 2-(2-butoxyethoxy)ethanol is 12: 10: 50: 2: 12.

[0047] Comparative Example 1

[0048] The difference from Example 3 is that in the preparation of the dispersant, the mass ratio of N-dodecyl succinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridineamine, and 2-(2-butoxyethoxy)ethanol is 0: 22: 50: 2: 12.

[0049] Comparative Example 2

[0050] The difference from Example 3 is that in the preparation of the dispersant, the mass ratio of N-dodecyl succinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridineamine, and 2-(2-butoxyethoxy)ethanol is 22: 0: 50: 2: 12.

[0051] Comparative Example 3

[0052] The difference from Example 3 lies in that in the preparation of the dispersant, the mass ratio of N-dodecyl succinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridinamine, and 2-(2-butoxyethoxy)ethanol is 24:10:50:2:0.

[0053] Comparative Example 4

[0054] The difference from Example 3 lies in that a preparation process of ultrafine highly dispersed cobalt oxide includes the following steps:

[0055] S1. Take cobalt nitrate hexahydrate and deionized water and mix them, stir for 20 min to obtain a cobalt nitrate solution; the concentration of the cobalt nitrate solution is 0.2 mol / L;

[0056] S2. Take the cobalt nitrate solution, adjust the pH to 9.5, age at 10°C for 24 h, perform centrifugal separation, take the solid phase and wash it to obtain Material A;

[0057] S3. Take Material A and place it in a 100 mL autoclave, add absolute ethanol and n-butanol, stir for 40 min, purge the autoclave with nitrogen to remove the air in the autoclave, seal it, pressurize and heat while stirring for 40 min, discharge the fluid in the autoclave, and cool the solid phase material in the autoclave to obtain Material B; the mass ratio of Material A, absolute ethanol, and n-butanol is 10:30:20; the pressurized heating means a pressure of 7.2 MPa and a temperature of 280°C;

[0058] S4. Take Material B and calcine it in a muffle furnace, grind it, and sieve it to obtain the ultrafine highly dispersed cobalt oxide; the calcination means heating to 500°C at a rate of 8°C / min and calcining for 5 h.

[0059] Comparative Example 5

[0060] The difference from Example 3 lies in that a preparation process of ultrafine highly dispersed cobalt oxide includes the following steps:

[0061] S1. Take cobalt nitrate hexahydrate and deionized water and mix them, stir for 20 min to obtain a cobalt nitrate solution; the concentration of the cobalt nitrate solution is 0.2 mol / L;

[0062] S2. Take the cobalt nitrate solution, add a dispersant, stir for 40 min, adjust the pH to 9.5, age at 10°C for 24 h, perform centrifugal separation, take the solid phase and wash it to obtain Material A; the dosage ratio of the cobalt nitrate solution to the dispersant is 12 mL:3 g;

[0063] S3. Place the material A in a 100 mL autoclave, add absolute ethanol, stir for 40 min, purge the autoclave with nitrogen to remove the air inside the autoclave, seal it, pressurize, heat and stir for 40 min, discharge the fluid inside the autoclave, and cool the solid-phase material inside the autoclave to obtain material B; the mass ratio of the material A to the absolute ethanol is 10:30; the pressurized heating means a pressure of 7.2 MPa and a temperature of 280 °C.

[0064] S4. Place the material B in a muffle furnace for calcination, grinding, and sieving to obtain the ultrafine highly dispersed cobalt oxide; the calcination means heating to 500 °C at a rate of 8 °C / min and calcining for 5 h.

[0065] Performance Test

[0066] Perform particle size tests on the cobalt oxides prepared in Examples 1-3 and Comparative Examples 1-5, and conduct high-resolution scanning electron microscope tests and tapped density tests on the cobalt oxide powders prepared in Examples 1-3 and Comparative Examples 1-5. The specific method is to disperse the samples under ultrasonic waves, then use a capillary to drop the suspension of suspended particles onto the sample stage with conductive glue, spray molten gold solution before the reaction, and finally place the sample stage into the SEM instrument for scanning tests. The data are shown in Table 1.

[0067] Table 1

[0068] Average particle size Tap density (g / mL) Example 1 Uniform in size, 32 nm 2.31 Example 2 Uniform in size, 28 nm 2.35 Example 3 Uniform in size, 31 nm 2.32 Comparative Example 1 Relatively uniform in size, 82 nm 2.07 Comparative Example 2 Relatively uniform in size, 79 nm 2.12 Comparative Example 3 Relatively uniform in size, 84 nm 2.09 Comparative Example 4 Non-uniform in size, 200 nm 0.96 Comparative Example 5 Relatively uniform in size, 105 nm 1.75

[0069] As can be seen from Table 1, the cobalt oxides prepared in Examples 1-3 of the present application have uniform sizes, excellent tapped densities, and smooth surfaces.

[0070] The above is only a preferred embodiment of the present invention and does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to make equivalent embodiments with equivalent changes, but as long as the technical content of the present invention is not departed from, any brief modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A process for preparing ultrafine highly dispersed cobalt oxide, characterized in that: The following steps are involved: S1. Mix cobalt nitrate hexahydrate and deionized water, and stir for 15-20 minutes to obtain a cobalt nitrate solution; S2, take the cobalt nitrate solution, add a dispersant, stir for 30-40 min, adjust the pH to 9.2-9.5, age at 5-10 ° C for 24 h, centrifuge, take the solid phase for washing, and obtain material A; S3, taking the material A and placing it in a 100mL autoclave, adding anhydrous ethanol and n-butanol, stirring for 30-40min, purging the autoclave with nitrogen to drive out the air in the autoclave, sealing, pressurizing, heating and stirring for 30-40min, discharging the fluid in the autoclave, cooling the solid phase material in the autoclave, and obtaining material B; S4, taking the material B, placing it in a muffle furnace for calcination, grinding, and sieving to obtain the ultrafine and highly dispersed cobalt oxide; The preparation of the dispersant comprises the following steps: N-dodecyl succinic anhydride, L-tert-leucine and acetone were mixed, ultrasonically dispersed for 25-35 minutes, N,N-dimethyl-4-pyridinamine was added, and the mixture was stirred at 35-45° C. for 3-4 hours, 2-(2-butoxyethoxy)ethanol was added, and the mixture was stirred for 1-2 hours and the acetone was removed by rotary evaporation to obtain the dispersant; Wherein, the mass ratio of N-dodecylsuccinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridinamine and 2-(2-butoxyethoxy)ethanol is 10-12:8-10:50:1-2:10-12.

2. The process for preparing ultrafine highly dispersed cobalt oxide according to claim 1, characterized in that: In step S1, the concentration of the cobalt nitrate solution is 0.2 mol / L.

3. The process for preparing ultrafine highly dispersed cobalt oxide according to claim 1, characterized in that: In step S2, the dosage ratio of the cobalt nitrate solution to the dispersant is 10-12 mL: 2-3 g.

4. The process for preparing ultrafine highly dispersed cobalt oxide according to claim 1, characterized in that: In step S3, the mass ratio of material A, anhydrous ethanol and n-butanol is 8-10:30:

20.

5. The process for preparing ultrafine highly dispersed cobalt oxide according to claim 1, characterized in that: In step S3, the pressurized heating refers to a pressure of 6.9-7.2 MPa and a temperature of 260-280°C.

6. The process for preparing ultrafine highly dispersed cobalt oxide according to claim 1, characterized in that: In step S4, the calcination refers to heating to 400-500° C. at a rate of 5-8° C. / min and calcining for 3-5 hours.