Method for preparing uniformly-coated high-voltage lithium cobalt oxide by complexing-hydrothermal method
The uniformly coated high-voltage lithium cobalt oxide was prepared by complex-hydrothermal method, which solved the problem of uneven coating of lithium cobalt oxide material, and achieved excellent electrochemical performance at high voltage, especially in terms of cyclic performance.
Patent Information
- Application Number
- CN202510686472.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-27
- Publication Date
- 2025-07-18
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
In the prior art, the coating layer of lithium cobalt oxide material is uneven, resulting in limited improvement in electrochemical performance at high voltages.
By using the complex-hydrothermal method, the complexing agent and surfactant were added to the aluminum salt solution, the pH was adjusted to neutral and reacted with lithium cobalt oxide, followed by drying and calcining, and uniformly coated high-voltage lithium cobalt oxide, which consists of betaine-type and sulfonate surfactant.
The uniformity of the coating layer of high voltage lithium cobalt oxide is improved, and its electrochemical performance is improved, especially at high voltages, which show excellent cycling stability and electrochemical performance.
Smart Images
Figure CN120328636A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of lithium ion batteries, and particularly to a method for preparing high-voltage lithium cobaltate with uniform coating by a complexation-hydrothermal method. Background Art
[0002] Due to the advantages of high energy density of lithium cobaltate materials, they have been widely used in 3C electronic products. However, the actual discharge specific capacity of current lithium cobaltate materials is far lower than their theoretical specific capacity. Therefore, the development of lithium cobaltate materials with high discharge specific capacity has become the research focus.
[0003] Existing improvement strategies include improving the crystal structure stability of materials by introducing doping ions and stabilizing the electrode / electrolyte interface stability performance through surface coating. However, there is a problem of uneven coating layer, which has limited improvement on the electrochemical performance of lithium cobaltate at high voltages. Summary of the Invention
[0004] Based on the technical problems existing in the background art, the present invention proposes a method for preparing high-voltage lithium cobaltate with uniform coating by a complexation-hydrothermal method, which improves the uniformity of the coating layer of high-voltage lithium cobaltate.
[0005] The method for preparing high-voltage lithium cobaltate with uniform coating by the complexation-hydrothermal method proposed by the present invention comprises the following steps: S1: Add a complexing agent to an aluminum salt solution and adjust the pH to neutral. S2: Add lithium cobaltate and a surfactant to the solution of S1, mix well and carry out a hydrothermal reaction. S3: Dry and calcine the product after the reaction of S2 to obtain high-voltage lithium cobaltate with uniform coating. Wherein, the surfactant is composed of a betaine-type surfactant and a sulfonate surfactant in a mass ratio of 3:1-9.
[0006] Preferably, the preparation method of the betaine-type surfactant is as follows: S11: Mix and react lauric acid, 3-dimethylaminopropylamine and a catalyst. S12: React sodium chloroacetate and the product after the reaction of S11 in a solvent to prepare the betaine-type surfactant.
[0007] Preferably, the mass ratio of lauric acid, 3-dimethylaminopropylamine and the catalyst in S11 is 100:50-60:0.5-1.
[0008] Preferably, the catalyst in S11 is sodium hydroxide or potassium hydroxide.
[0009] Preferably, the reaction temperature in S11 is 150-170°C and the reaction time is 6-12 h.
[0010] Preferably, the mass ratio of sodium chloroacetate to the product after the reaction in S12 is 1:0.8 - 1; the reaction temperature is 70 - 90°C, and the reaction time is 4 - 8 h.
[0011] Preferably, the preparation method of the sulfonate surfactant is as follows: oleic acid is esterified with butanol and then reacted with sodium sulfite to obtain the sulfonate surfactant.
[0012] Preferably, the mass ratio of the aluminum salt, complexing agent, lithium cobaltate, and surfactant in S1 is 1:1 - 1.2:10 - 15:0.01 - 0.1; the aluminum salt is aluminum nitrate; the complexing agent is disodium ethylenediaminetetraacetate.
[0013] Preferably, the temperature of the hydrothermal reaction in S2 is 140 - 160°C, and the time is 1 - 5 h.
[0014] Preferably, the temperature of the calcination in S3 is 300 - 500°C, and the time is 1 - 3 h.
[0015] Advantages and beneficial technical effects of the present invention: By first complexing the aluminum salt and then performing a hydrothermal reaction with lithium cobaltate, the present invention prepares a material in which metal ion compounds uniformly coat lithium cobaltate after calcination. This material has excellent electrochemical performance. In addition, a surfactant is added in the hydrothermal reaction of the present invention, which can further improve the electrochemical performance of the material. Moreover, the surfactant of the present invention is composed of a betaine-type surfactant and a sulfonate surfactant, which has a synergistic promoting effect on improving the electrochemical performance of the material. Description of the drawings
[0016] Figure 1 TEM images of lithium cobaltate before (a) and after (b) coating in Example 1 proposed by the present invention. Detailed implementation manners
[0017] The following further explains the present invention with reference to specific examples.
[0018] The synthesis route of the betaine-type surfactant in the examples of the present invention is as follows: .
[0019] The synthesis route of the sulfonate surfactant in the examples of the present invention is as follows. Specific reaction conditions, raw material ratios, etc. can all adopt existing technologies. The preparation methods of the sulfonate surfactants involved in the examples and comparative examples of the present invention are all the same: .
[0020] Example 1
[0021] Add 11 g of disodium ethylenediaminetetraacetate to a solution containing 10 g of aluminum nitrate, and adjust the pH to neutral; add 120 g of lithium cobaltate and 0.5 g of surfactant to the solution, mix well, and carry out hydrothermal reaction at 150 °C for 3 h; dry and calcine the reaction product, the calcination temperature is 400 °C, the time is 2 h, and uniformly coated high-voltage lithium cobaltate is obtained after calcination.
[0022] Among them, the surfactant is composed of a betaine-type surfactant and a sulfonate surfactant in a mass ratio of 1:1.
[0023] The preparation method of the betaine-type surfactant is as follows: mix 10 g of lauric acid, 5.5 g of 3-dimethylaminopropylamine and 0.08 g of potassium hydroxide for reaction, the reaction temperature is 160 °C, and the reaction time is 8 h; then react 10 g of sodium chloroacetate and 9 g of the above product in a solvent at 80 °C for 6 h to obtain the betaine-type surfactant.
[0024] The preparation method of the sulfonate surfactant is: after oleic acid is esterified with butanol, it is then reacted with sodium sulfite to obtain the sulfonate surfactant.
[0025] Example 2
[0026] Add 10 g of disodium ethylenediaminetetraacetate to a solution containing 10 g of aluminum nitrate, and adjust the pH to neutral; add 100 g of lithium cobaltate and 0.1 g of surfactant to the solution, mix well, and carry out hydrothermal reaction at 140 °C for 5 h; dry and calcine the reaction product, the calcination temperature is 300 °C, the time is 3 h, and uniformly coated high-voltage lithium cobaltate is obtained after calcination.
[0027] Among them, the surfactant is composed of a betaine-type surfactant and a sulfonate surfactant in a mass ratio of 3:1.
[0028] The preparation method of the betaine-type surfactant is as follows: mix 10 g of lauric acid, 5 g of 3-dimethylaminopropylamine and 0.05 g of potassium hydroxide for reaction, the reaction temperature is 150 °C, and the reaction time is 6 h; then react 10 g of sodium chloroacetate and 8 g of the above product in a solvent at 70 °C for 4 h to obtain the betaine-type surfactant.
[0029] The preparation method of the sulfonate surfactant is: after oleic acid is esterified with butanol, it is then reacted with sodium sulfite to obtain the sulfonate surfactant.
[0030] Example 3
[0031] Add 12 g of disodium ethylenediaminetetraacetate to a solution containing 10 g of aluminum nitrate, and adjust the pH to neutral. Add 150 g of lithium cobaltate and 1 g of surfactant to the solution, mix well, and then carry out a hydrothermal reaction at 160 °C for 1 h. Dry and calcine the reaction product at a calcination temperature of 500 °C for 1 h to obtain high-voltage lithium cobaltate with uniform coating.
[0032] Among them, the surfactant is composed of a betaine-type surfactant and a sulfonate surfactant in a mass ratio of 1:3.
[0033] The preparation method of the betaine-type surfactant is as follows: Mix 10 g of lauric acid, 6 g of 3-dimethylaminopropylamine, and 0.1 g of potassium hydroxide for reaction at a reaction temperature of 170 °C for 12 h. Then react 10 g of sodium chloroacetate and 10 g of the above product in a solvent at 90 °C for 8 h to obtain the betaine-type surfactant.
[0034] The preparation method of the sulfonate surfactant is: React oleic acid with butanol for esterification and then react with sodium sulfite to obtain the sulfonate surfactant.
[0035] Example 4
[0036] Add 11 g of disodium ethylenediaminetetraacetate to a solution containing 10 g of aluminum nitrate, and adjust the pH to neutral. Add 120 g of lithium cobaltate and 0.5 g of surfactant to the solution, mix well, and then carry out a hydrothermal reaction at 150 °C for 3 h. Dry and calcine the reaction product at a calcination temperature of 350 °C for 2 h to obtain high-voltage lithium cobaltate with uniform coating.
[0037] Among them, the surfactant is composed of a betaine-type surfactant and a sulfonate surfactant in a mass ratio of 1:1.
[0038] The preparation method of the betaine-type surfactant is as follows: Mix 10 g of lauric acid, 5.5 g of 3-dimethylaminopropylamine, and 0.08 g of potassium hydroxide for reaction at a reaction temperature of 160 °C for 8 h. Then react 10 g of sodium chloroacetate and 9 g of the above product in a solvent at 80 °C for 6 h to obtain the betaine-type surfactant.
[0039] The preparation method of the sulfonate surfactant is: React oleic acid with butanol for esterification and then react with sodium sulfite to obtain the sulfonate surfactant.
[0040] Example 5
[0041] Add 11 g of disodium ethylenediaminetetraacetate to a solution containing 10 g of aluminum nitrate, and adjust the pH to neutral. Add 120 g of lithium cobaltate and 0.5 g of surfactant to the solution, mix well, and carry out a hydrothermal reaction at 150 °C for 3 h. Dry and calcine the reaction product, with the calcination temperature being 450 °C and the time being 2 h, to obtain high-voltage lithium cobaltate with uniform coating.
[0042] Among them, the surfactant is composed of a betaine-type surfactant and a sulfonate surfactant in a mass ratio of 1:1.
[0043] The preparation method of the betaine-type surfactant is as follows: Mix 10 g of lauric acid, 5.5 g of 3-dimethylaminopropylamine, and 0.08 g of potassium hydroxide for reaction at a reaction temperature of 160 °C and a reaction time of 8 h. Then react 10 g of sodium chloroacetate and 9 g of the above product in a solvent at 80 °C for 6 h to obtain the betaine-type surfactant.
[0044] The preparation method of the sulfonate surfactant is: Esterify oleic acid with butanol and then react with sodium sulfite to obtain the sulfonate surfactant.
[0045] Example 6
[0046] Add 11 g of disodium ethylenediaminetetraacetate to a solution containing 10 g of aluminum nitrate, and adjust the pH to neutral. Add 120 g of lithium cobaltate and 0.5 g of surfactant to the solution, mix well, and carry out a hydrothermal reaction at 145 °C for 3 h. Dry and calcine the reaction product, with the calcination temperature being 400 °C and the time being 2 h, to obtain high-voltage lithium cobaltate with uniform coating.
[0047] Among them, the surfactant is composed of a betaine-type surfactant and a sulfonate surfactant in a mass ratio of 1:1.
[0048] The preparation method of the betaine-type surfactant is as follows: Mix 10 g of lauric acid, 5.5 g of 3-dimethylaminopropylamine, and 0.08 g of potassium hydroxide for reaction at a reaction temperature of 160 °C and a reaction time of 8 h. Then react 10 g of sodium chloroacetate and 9 g of the above product in a solvent at 80 °C for 6 h to obtain the betaine-type surfactant.
[0049] The preparation method of the sulfonate surfactant is: Esterify oleic acid with butanol and then react with sodium sulfite to obtain the sulfonate surfactant.
[0050] Example 7
[0051] Add 11 g of disodium ethylenediaminetetraacetate to a solution containing 10 g of aluminum nitrate, and adjust the pH to neutral; add 120 g of lithium cobaltate and 0.5 g of surfactant to the solution, mix well, and carry out a hydrothermal reaction at 155 °C for 3 h; dry and calcine the reaction product, the calcination temperature is 400 °C, the time is 2 h, and uniformly coated high-voltage lithium cobaltate is obtained after calcination.
[0052] Among them, the surfactant is composed of a betaine-type surfactant and a sulfonate surfactant in a mass ratio of 1:1.
[0053] The preparation method of the betaine-type surfactant is as follows: Mix 10 g of lauric acid, 5.5 g of 3-dimethylaminopropylamine and 0.08 g of potassium hydroxide for reaction, the reaction temperature is 160 °C, and the reaction time is 8 h; then react 10 g of sodium chloroacetate and 9 g of the above product in a solvent at 80 °C for 6 h to obtain the betaine-type surfactant.
[0054] The preparation method of the sulfonate surfactant is: After esterifying oleic acid with butanol, react it with sodium sulfite to obtain the sulfonate surfactant.
[0055] Example 8
[0056] Add 11 g of disodium ethylenediaminetetraacetate to a solution containing 10 g of aluminum nitrate, and adjust the pH to neutral; add 120 g of lithium cobaltate and 0.5 g of surfactant to the solution, mix well, and carry out a hydrothermal reaction at 150 °C for 3 h; dry and calcine the reaction product, the calcination temperature is 400 °C, the time is 2 h, and uniformly coated high-voltage lithium cobaltate is obtained after calcination.
[0057] Among them, the surfactant is composed of a betaine-type surfactant and a sulfonate surfactant in a mass ratio of 2:1.
[0058] The preparation method of the betaine-type surfactant is as follows: Mix 10 g of lauric acid, 5.5 g of 3-dimethylaminopropylamine and 0.08 g of potassium hydroxide for reaction, the reaction temperature is 160 °C, and the reaction time is 8 h; then react 10 g of sodium chloroacetate and 9 g of the above product in a solvent at 80 °C for 6 h to obtain the betaine-type surfactant.
[0059] The preparation method of the sulfonate surfactant is: After esterifying oleic acid with butanol, react it with sodium sulfite to obtain the sulfonate surfactant.
[0060] Example 9
[0061] Add 11 g of disodium ethylenediaminetetraacetate to a solution containing 10 g of aluminum nitrate, and adjust the pH to neutral; add 120 g of lithium cobaltate and 0.5 g of surfactant to the solution, mix well, and perform a hydrothermal reaction at 150 °C for 3 h; dry and calcine the reaction product, the calcination temperature is 400 °C, and the time is 2 h. After calcination, high-voltage lithium cobaltate with uniform coating is obtained.
[0062] Among them, the surfactant is composed of a betaine-type surfactant and a sulfonate surfactant in a mass ratio of 1:2.
[0063] The preparation method of the betaine-type surfactant is as follows: Mix 10 g of lauric acid, 5.5 g of 3-dimethylaminopropylamine, and 0.08 g of potassium hydroxide for reaction, the reaction temperature is 160 °C, and the reaction time is 8 h; then react 10 g of sodium chloroacetate and 9 g of the above product in a solvent at 80 °C for 6 h to obtain the betaine-type surfactant.
[0064] The preparation method of the sulfonate surfactant is: esterify oleic acid with butanol and then react with sodium sulfite to obtain the sulfonate surfactant.
[0065] Comparative Example 1 Add 11 g of disodium ethylenediaminetetraacetate to a solution containing 10 g of aluminum nitrate, and adjust the pH to neutral; add 120 g of lithium cobaltate to the solution, mix well, and perform a hydrothermal reaction at 150 °C for 3 h; dry and calcine the reaction product, the calcination temperature is 400 °C, and the time is 2 h. After calcination, high-voltage lithium cobaltate with uniform coating is obtained.
[0066] Comparative Example 2 Add 11 g of disodium ethylenediaminetetraacetate to a solution containing 10 g of aluminum nitrate, and adjust the pH to neutral; add 120 g of lithium cobaltate and 0.5 g of betaine-type surfactant to the solution, mix well, and perform a hydrothermal reaction at 150 °C for 3 h; dry and calcine the reaction product, the calcination temperature is 400 °C, and the time is 2 h. After calcination, high-voltage lithium cobaltate with uniform coating is obtained.
[0067] The preparation method of the betaine-type surfactant is as follows: Mix 10 g of lauric acid, 5.5 g of 3-dimethylaminopropylamine, and 0.08 g of potassium hydroxide for reaction, the reaction temperature is 160 °C, and the reaction time is 8 h; then react 10 g of sodium chloroacetate and 9 g of the above product in a solvent at 80 °C for 6 h to obtain the betaine-type surfactant.
[0068] Comparative Example 3 Add 11 g of disodium ethylenediaminetetraacetate to a solution containing 10 g of aluminum nitrate, and adjust the pH to neutral; add 120 g of lithium cobaltate and 0.5 g of sulfonate surfactant to the solution, mix well, and perform hydrothermal reaction at 150 °C for 3 h; dry and calcine the reaction product, the calcination temperature is 400 °C, and the time is 2 h. After calcination, high-voltage lithium cobaltate with uniform coating is obtained.
[0069] The preparation method of the sulfonate surfactant is as follows: oleic acid is esterified with butanol and then reacted with sodium sulfite to obtain the sulfonate surfactant.
[0070] Figure 1 Figure TEM before and after coating of lithium cobaltate in Example 1. It can be seen that the surface of the lithium cobaltate of the present invention is uniformly coated with a metal ion compound layer.
[0071] Test the electrochemical performance of the high-voltage lithium cobaltate prepared in Example 1 and Comparative Examples 1-3 as the cathode material. The test results are shown in Table 1.
[0072] The test method is as follows: mix the lithium cobaltate cathode material, conductive carbon black and polyvinylidene fluoride binder in a mass ratio of 90:5:5 in N,N-dimethylpyrrolidone, scrape and coat it on the surface of aluminum foil, dry it in a vacuum oven at 120 °C, roll it, and cut it into a cathode sheet with a diameter of 14 mm. Use a lithium metal sheet as the anode, select Celgard 2400 membrane as the separator, the electrolyte composition is 1 mol / L LiPF6 / EC+DMC, and assemble a CR2025 type button battery in an argon atmosphere glove box for charge and discharge cycle testing.
[0073] Table 1 Test results of electrochemical performance of high-voltage lithium cobaltate Group Initial ring capacity (mAh / g) Capacity after 100 cycles (mAh / g) Capacity after 200 cycles (mAh / g) Example 1 215.4 184.1 176.3 Comparative Example 1 204.8 129.3 114.8 Comparative Example 2 209.7 154.9 142.1 Comparative Example 3 212.5 161.4 148.6 From the test results in Table 1, it can be seen that the high-voltage lithium cobaltate prepared by the present invention has excellent electrochemical performance, and the capacity can still remain above 80% after 200 cycles of cyclic discharge; from the test results of Example 1 and Comparative Example 1, it can be seen that by adding a surfactant in the hydrothermal reaction, the present invention can further improve the electrochemical performance of the material; while the test results of Example 1 and Comparative Examples 2-3 further prove that when the surfactant of the present invention is composed of a betaine-type surfactant and a sulfonate surfactant, it has a synergistic promoting effect on improving the electrochemical performance of the material. This is because the surfactant of the present invention can not only make the coating layer more uniform, but also improve the interfacial stability, realizing the regulation of the microstructure, so that the coated high-voltage lithium cobaltate has excellent electrochemical performance.
[0074] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application. The scope of the present application is defined by the appended claims and their equivalents, and all of them should be included within the protection scope of the present application.
Claims
1. A method for preparing high-voltage lithium cobaltate with uniform coating by a complexation-hydrothermal method, characterized in that, The method steps are as follows: S1: Add a complexing agent to the aluminum salt solution and adjust the pH to neutral; S2: Add lithium cobaltate and a surfactant to the solution in S1, mix well and carry out a hydrothermal reaction; S3: Dry and calcine the product after the reaction in S2 to obtain high-voltage lithium cobaltate with uniform coating; Among them, the surfactant is composed of a betaine-type surfactant and a sulfonate surfactant in a mass ratio of 3:1-9.
2. The method for preparing high-voltage lithium cobaltate with uniform coating by complexation-hydrothermal method according to claim 1, wherein, The preparation method of the betaine-type surfactant is as follows: S11: Mix and react lauric acid, 3-dimethylaminopropylamine and a catalyst; S12: React sodium chloroacetate with the product after the reaction in S11 in a solvent to prepare a betaine-type surfactant.
3. The method for preparing high-voltage lithium cobaltate with uniform coating by the complexation-hydrothermal method according to claim 2, characterized in that, In S11, the mass ratio of lauric acid, 3-dimethylaminopropylamine and the catalyst is 100:50-60:0.5-1.
4. The method for preparing high-voltage lithium cobaltate with uniform coating by complexation-hydrothermal method according to claim 2, characterized in that, The catalyst in S11 is sodium hydroxide or potassium hydroxide.
5. The method for preparing uniformly coated high-voltage lithium cobaltate by complexation-hydrothermal method according to claim 2, characterized in that, In S11, the reaction temperature is 150-170°C and the reaction time is 6-12 h.
6. The method for preparing high-voltage lithium cobaltate with uniform coating by complexation-hydrothermal method according to claim 2, characterized in that, In S12, the mass ratio of sodium chloroacetate to the product after the reaction in S11 is 1:0.8-1; the reaction temperature is 70-90°C and the reaction time is 4-8 h.
7. The method for preparing high-voltage lithium cobaltate with uniform coating by complexation-hydrothermal method according to claim 1, characterized in that, The preparation method of the sulfonate surfactant is: esterify oleic acid with butanol and then react with sodium sulfite to prepare the sulfonate surfactant.
8. The method for preparing high-voltage lithium cobaltate with uniform coating by complexation-hydrothermal method according to claim 1, characterized in that, In S1, the mass ratio of the aluminum salt, complexing agent, lithium cobaltate and surfactant is 1:1-1.2:10-15: 0.01-0.1; the aluminum salt is aluminum nitrate; the complexing agent is disodium ethylenediaminetetraacetate.
9. The method for preparing high-voltage lithium cobaltate with uniform coating by complexation-hydrothermal method according to claim 1, characterized in that, In S2, the temperature of the hydrothermal reaction is 140-160°C and the time is 1-5 h.
10. The method for preparing high-voltage lithium cobalt oxide with uniform coating by the complexation-hydrothermal method according to claim 1, characterized in that, In S3, the calcination temperature is 300-500°C and the time is 1-3 h.