Preparation method of high-aluminum-doped small-particle-size cobaltosic oxide
By controlling the concentration and ratio of aluminum salt and cobalt salt in the cobalt-aluminum mixed solution, a high-aluminum doping small-particle cobalt tetroxide was prepared, which solved the problem of segregation of aluminum element distribution, improved the uniformity of aluminum doping and cobalt content, and achieved a low-cost and efficient preparation process.
Patent Information
- Application Number
- CN202411715601.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2025-03-07
AI Technical Summary
When preparing cobalt tetroxide, as the amount of aluminum doping increases and the particle size decreases, the distribution of aluminum elements in cobalt tetroxide is prone to segregation, resulting in a decrease in the uniformity of aluminum doping.
By controlling the concentration and ratio of aluminum salt and cobalt salt in the cobalt-aluminum mixed solution, small-particle cobalt tetroxide was prepared, which improved the amount of aluminum doping and the uniformity of aluminum doping. The specific steps include configuring a cobalt-aluminum mixed solution and an alkali solution, and after the reaction, it is allowed to stand, press filtration, washing, drying, and crushing, and finally calcining to obtain high-aluminum-doped small-particle cobalt tetroxide.
The aluminum doping amount and uniformity of the small-particle cobalt tetroxide are improved, the cobalt content reaches 64.19%-65.71%, and the aluminum doping amount reaches 7853-9645ppm. The preparation process is low and the cycle is short, which reduces the preparation cost and is conducive to large-scale production.
Smart Images
Figure CN119569135A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of electrode materials, and in particular to a method for preparing highly aluminum-doped small-particle cobalt tetroxide. Background Art
[0002] Cobalt tetroxide is often used to synthesize lithium cobalt oxide positive electrode materials, and is also used as a substitute for carbon negative electrodes. It is also widely used in catalysts, supercapacitors, inorganic pigments and other fields.
[0003] At present, with the rapid development of electronic devices, higher requirements are put forward for the rate performance of lithium-ion battery positive electrode materials. In order to improve the rate performance of lithium cobalt oxide, small-particle cobalt tetroxide is used in the synthesis of lithium cobalt oxide, which is conducive to shortening the ion channel during the charging and discharging process of lithium ions. In order to meet the demand for higher voltage, aluminum doping is used to increase the stability of the lithium cobalt oxide lattice, so aluminum-doped small-particle cobalt tetroxide is used to synthesize lithium cobalt oxide.
[0004] However, when preparing cobalt tetroxide, as the amount of aluminum doping increases and the particle size decreases, the distribution of aluminum in cobalt tetroxide tends to segregate, resulting in a decrease in the uniformity of aluminum doping in cobalt tetroxide. Summary of the invention
[0005] In view of the shortcomings of the above-mentioned related technologies, the present application provides a method for preparing highly aluminum-doped small-particle cobalt tetroxide. The present application prepares small-particle cobalt tetroxide by controlling the concentration and ratio of aluminum salt and cobalt salt in a cobalt-aluminum mixed solution, thereby increasing the aluminum doping amount and aluminum doping uniformity of the small-particle cobalt tetroxide.
[0006] The present application provides a method for preparing highly aluminum-doped small-particle cobalt tetroxide using the following technical solution:
[0007] A method for preparing highly aluminum-doped small-particle cobalt tetroxide comprises the following steps: using cobalt salt and aluminum salt to prepare a cobalt-aluminum mixed solution, and preparing an alkaline solution for standby use; adding a base liquid and an oxidant into a reaction container; flowing the cobalt-aluminum mixed solution and the alkaline solution into the reaction container in parallel for reaction; after the reaction is completed, standing and aging, filter pressing, washing, drying, and crushing to obtain a precursor; calcining the precursor to obtain the highly aluminum-doped small-particle cobalt tetroxide, wherein the weight ratio of the cobalt salt to the aluminum salt is 13-17:1.
[0008] Preferably, the mass concentration of the cobalt salt in the cobalt-aluminum mixed solution is 100-140 g / L.
[0009] Preferably, the mass concentration of cobalt salt in the cobalt-aluminum mixed solution is 130 g / L.
[0010] Preferably, the mass concentration of aluminum salt in the cobalt-aluminum mixed solution is 6-12 g / L.
[0011] Preferably, the mass concentration of aluminum salt in the cobalt-aluminum mixed solution is 10 g / L.
[0012] Preferably, the cobalt salt includes one or both of cobalt chloride and cobalt sulfate.
[0013] Preferably, the cobalt salt is cobalt chloride.
[0014] Preferably, the aluminum salt comprises one or both of aluminum chloride and aluminum sulfate.
[0015] Preferably, the aluminum salt is aluminum chloride.
[0016] Preferably, the oxidant comprises one or both of a sodium hypochlorite solution and a potassium chlorate solution.
[0017] Preferably, the oxidizing agent is sodium hypochlorite solution.
[0018] Preferably, the mass concentration of the oxidant is 8-14%.
[0019] Preferably, the mass concentration of the oxidant is 12%.
[0020] Preferably, the flow ratio of the cobalt-aluminum mixed solution and the alkaline solution introduced into the reaction container in parallel is 1:0.5-0.7.
[0021] Preferably, the flow ratio of the cobalt-aluminum mixed solution and the alkaline solution introduced into the reaction container in parallel is 1:0.6.
[0022] Preferably, the flow rate of the cobalt-aluminum mixed solution is 30 L / h.
[0023] Preferably, the flow rate of the alkaline solution is 18 L / h.
[0024] Preferably, the alkaline solution comprises one or both of sodium hydroxide solution and ammonia water.
[0025] Preferably, the alkaline solution is a sodium hydroxide solution.
[0026] Preferably, the calcination temperature is 650-750° C. and the calcination time is 5-7 hours.
[0027] Preferably, the calcination temperature is 700° C. and the calcination time is 6 hours.
[0028] Preferably, the cobalt content of the highly aluminum-doped small-particle cobalt tetroxide is 64.19%-65.71%, and the aluminum-doped amount is 7853-9645 ppm.
[0029] In summary, the present application includes at least one of the following beneficial technical effects:
[0030] 1. Small-particle cobalt tetroxide is prepared by controlling the concentration and ratio of aluminum salt and cobalt salt in the cobalt-aluminum mixed solution, thereby increasing the aluminum doping amount and aluminum doping uniformity of the small-particle cobalt tetroxide;
[0031] 2. The aluminum-doped cobalt tetroxide prepared in the present application has a cobalt content of 64.19%-65.71% and an aluminum-doped amount of 7853-9645 ppm when the particle size D100 is less than 5 μm.
[0032] 3. The preparation process of aluminum-doped cobalt tetroxide in the present application is low in difficulty, short in cycle, mild in conditions, reduces the preparation cost, and is conducive to large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 This is a scanning electron microscope image of highly aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Example 1 in this application.
[0034] Figure 2 This is the energy spectrum of highly aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Example 1 in this application.
[0035] Figure 3 This is a scanning electron microscope image of highly aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Example 2 in this application.
[0036] Figure 4 This is the energy spectrum of highly aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Example 2 in this application.
[0037] Figure 5 This is a scanning electron microscope image of highly aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Example 3 in this application.
[0038] Figure 6 This is the energy spectrum of highly aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Example 3 in this application.
[0039] Figure 7 This is a scanning electron microscope image of cobalt tetroxide prepared by the preparation method of Comparative Example 1.
[0040] Figure 8 This is the energy spectrum of cobalt tetroxide prepared by the preparation method of Comparative Example 1.
[0041] Fig. 9 This is a scanning electron microscope image of cobalt tetroxide prepared by the preparation method of Comparative Example 3.
[0042] Fig.10 This is a scanning electron microscope image of cobalt tetroxide prepared by the preparation method of Comparative Example 4. DETAILED DESCRIPTION
[0043] The present application is further described in detail below in conjunction with examples. The following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. In the following examples, if specific conditions are not specified, they are carried out according to normal conditions or conditions recommended by the manufacturer. The methods used are conventional methods known in the art unless otherwise specified, and the consumables and reagents used are commercially available unless otherwise specified. Unless otherwise specified, the professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the recorded content may also be applied to the present invention.
[0044] The raw materials used in the examples and comparative examples can all be obtained commercially.
[0045] Example 1
[0046] Example 1 of the present application provides a method for preparing highly aluminum-doped small-particle cobalt tetroxide, and the specific steps are as follows: cobalt chloride and aluminum chloride are prepared into a cobalt-aluminum mixed solution with a cobalt chloride concentration of 130 g / L and an aluminum chloride concentration of 10 g / L, and a 4 mol / L sodium hydroxide solution is prepared for standby use, 25 L of sodium hydroxide solution is added to a reactor as a base liquid, and 6 L of a sodium hypochlorite solution with a mass fraction of 12% is added, stirring is started, and the stirring speed is 400 r / min, and the cobalt-aluminum mixed solution and the sodium hydroxide solution are introduced into the reactor in parallel for reaction for 10 min, the flow rate of the cobalt-aluminum mixed solution is 30 L / h, and the flow rate of the sodium hydroxide solution is 18 L / h. After the reaction is completed, it is statically aged, filtered, washed, dried, and crushed to obtain a precursor, and the precursor is kept at 700° C. for 6 h and calcined to obtain highly aluminum-doped small-particle cobalt tetroxide.
[0047] Example 2
[0048] Example 2 of the present application provides a method for preparing highly aluminum-doped small-particle cobalt tetroxide. The difference between Example 2 and Example 1 is that the concentration of cobalt chloride in the cobalt-aluminum mixed solution in Example 2 is 120 g / L, and the concentration of aluminum chloride is 7.4 g / L.
[0049] Example 3
[0050] Example 3 of the present application provides a method for preparing highly aluminum-doped small-particle cobalt tetroxide. The difference between Example 3 and Example 1 is that the concentration of cobalt chloride in the cobalt-aluminum mixed solution in Example 3 is 110 g / L, and the concentration of aluminum chloride is 7.64 g / L.
[0051] Comparative Example 1
[0052] Comparative Example 1 provides a method for preparing cobalt trioxide. The difference between Comparative Example 1 and Example 1 is that the concentration of cobalt chloride in the cobalt-aluminum mixed solution in Comparative Example 1 is 160 g / L, and the concentration of aluminum chloride is 12.34 g / L.
[0053] Comparative Example 2
[0054] Comparative Example 2 provides a method for preparing cobalt tetroxide. The difference between Comparative Example 2 and Example 1 is that the concentration of cobalt chloride in the cobalt-aluminum mixed solution in Comparative Example 2 is 90 g / L, and the concentration of aluminum chloride is 6.94 g / L.
[0055] Comparative Example 3
[0056] Comparative Example 3 provides a method for preparing cobalt trioxide. The difference between Comparative Example 3 and Example 1 is that the flow rate of the sodium hydroxide solution in Comparative Example 3 is 8 L / h.
[0057] Comparative Example 4
[0058] Comparative Example 4 provides a method for preparing cobalt trioxide. The difference between Comparative Example 4 and Example 1 is that the amount of 12% sodium hypochlorite solution added in Comparative Example 4 is 16L.
[0059] Test and Inspection
[0060] (1) The transmission electron microscope and energy spectrometer were used to detect the high-aluminum-doped small-particle cobalt tetroxide prepared by the preparation methods of Examples 1-3 and the cobalt tetroxide prepared by the preparation method of Comparative Example 1, respectively. Figure 1-8 As shown, transmission electron microscopy images of cobalt tetroxide prepared by the preparation methods of Comparative Examples 3 and 4 were obtained by transmission electron microscopy. Figure 9-10 shown.
[0061] (2) The aluminum doping amounts of the highly aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Examples 1-3 and the cobalt tetroxide prepared by the preparation method of Comparative Examples 1-4 at different sampling points were detected by atomic emission spectrometry (ICP), and the average aluminum doping amount (ppm) was obtained. The cobalt content (Co (%)) of the highly aluminum-doped small-particle cobalt tetroxide prepared by Examples 1-3 and the cobalt tetroxide prepared by the preparation method of Comparative Examples 1-4 was detected by EDTA titration, as shown in Table 1 below.
[0062] (3) Using a Mastersizer 3000 laser particle size analyzer, the particle sizes of the highly aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Examples 1-3 and the cobalt tetroxide prepared by the preparation method of Comparative Examples 1-4 were measured to obtain D50 and D100, as shown in Table 1 below.
[0063] Table 1:
[0064]
[0065]
[0066] Results Analysis
[0067] The following table 1 and Figure 1-10 The experimental results provided are used to explain this application in detail.
[0068] Reference Figure 1-6 and Table 1, by Figure 1 , 3 , 5 and D50 data in Table 1 show that the particle size of the highly aluminum-doped small-particle cobalt tetraoxide prepared by the preparation method of Examples 1-3 is as small as nearly 1 μm. Figure 2 , 4 6. It can be seen that the aluminum content of the high-aluminum-doped small-particle cobalt tetroxide prepared by the preparation methods of Examples 1-3 is uniform. Specifically, the cobalt content in the high-aluminum-doped small-particle cobalt tetroxide prepared by the preparation methods of Examples 1-3 is about 65%, and the theoretical aluminum content of the high-aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Example 1 is 10000ppm, the theoretical aluminum content of the high-aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Example 2 is 8000ppm, and the theoretical aluminum content of the high-aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Example 3 is 9000ppm. The actual aluminum content of the sample obtained is within ±400ppm of the calculated value, and the aluminum element is evenly distributed and the particle size is small.
[0069] Refer to Table 1 and Figure 7-10The theoretical aluminum doping amount of the cobalt tetroxide prepared by the preparation method of Comparative Examples 1-4 is 10000ppm, wherein the cobalt content of the cobalt tetroxide prepared by the preparation method of Comparative Examples 1-2 is much less than the cobalt content of the high-aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Example 1, wherein the cobalt content of the cobalt tetroxide prepared by the preparation method of Comparative Example 2 is only 56.97%, the average aluminum doping amount is only 6534ppm, and D100 reaches more than 20μm. The low cobalt content of the cobalt tetroxide prepared by the preparation method of Comparative Example 1 is due to incomplete precipitation caused by the high cobalt concentration, and the low aluminum content of the cobalt tetroxide prepared by the preparation method of Comparative Example 2 is due to the low cobalt concentration in the preparation process, which makes the aluminum element unable to be well doped, resulting in segregation; the cobalt content and average aluminum content of the cobalt tetroxide prepared by the preparation method of Comparative Example 3 are much lower than the cobalt content and average aluminum content of the high-aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Example 1, and the D50 and D100 of the cobalt tetroxide prepared by the preparation method of Comparative Example 3 are much higher than the D50 and D100 of the high-aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Example 1. It is analyzed that the low flow rate of the alkaline solution and the low pH result in the formation of a flaky morphology such as Figure 7 As shown, the particle size is large, the aluminum doping amount is low, and the aluminum doping is uneven; the cobalt content and the average aluminum doping amount of the cobalt tetroxide prepared by the preparation method of Comparative Example 4 are much lower than the cobalt content and the average aluminum doping amount of the high-aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Example 1, and the D100 of the cobalt tetroxide prepared by the preparation method of Comparative Example 4 is much higher than the D100 of the high-aluminum-doped small-particle cobalt tetroxide prepared by the preparation method of Example 1. Analysis shows that the addition amount of sodium hypochlorite solution is too high and the oxidation is too fast, resulting in the formation of block morphology, D100 becoming larger, and the aluminum doping amount is low, and the aluminum doping is uneven.
[0070] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.
Claims
1. A method for preparing highly aluminum-doped small-particle cobalt tetroxide, characterized in that: The following steps are involved: A cobalt-aluminum mixed solution is prepared using cobalt salt and aluminum salt, and an alkaline solution is prepared for standby use, a base liquid and an oxidant are added to a reaction container, the cobalt-aluminum mixed solution and the alkaline solution are introduced into the reaction container in parallel for reaction, after the reaction is completed, the solution is allowed to stand for aging, filter pressed, washed, dried, and crushed to obtain a precursor, the precursor is calcined to obtain the highly aluminum-doped small-particle cobalt tetroxide, and the weight ratio of the cobalt salt to the aluminum salt is 13-17:
1.
2. The method for preparing highly aluminum-doped small-particle cobalt tetroxide according to claim 1, characterized in that: The mass concentration of cobalt salt in the cobalt-aluminum mixed solution is 100-140 g / L.
3. The method for preparing highly aluminum-doped small-particle cobalt tetroxide according to claim 1, characterized in that: The mass concentration of aluminum salt in the cobalt-aluminum mixed solution is 6-12 g / L.
4. The method for preparing highly aluminum-doped small-particle cobalt tetroxide according to claim 1, characterized in that: The cobalt salt includes one or both of cobalt chloride and cobalt sulfate.
5. The method for preparing highly aluminum-doped small-particle cobalt tetroxide according to claim 1, characterized in that: The aluminum salt includes one or both of aluminum chloride and aluminum sulfate.
6. The method for preparing highly aluminum-doped small-particle cobalt tetroxide according to claim 1, characterized in that: The oxidant comprises one or both of a sodium hypochlorite solution and a potassium chlorate solution.
7. The method for preparing highly aluminum-doped small-particle cobalt tetroxide according to claim 1, characterized in that: The mass concentration of the oxidant is 8-14%.
8. The method for preparing highly aluminum-doped small-particle cobalt tetroxide according to claim 1, characterized in that: The cobalt-aluminum mixed solution and the alkaline solution are introduced into the reaction container in parallel, and the flow ratio of the cobalt-aluminum mixed solution to the alkaline solution is 1:0.5-0.
7.
9. The method for preparing highly aluminum-doped small-particle cobalt tetroxide according to claim 1, characterized in that: The alkaline solution includes one or both of sodium hydroxide solution and ammonia water.
10. The method for preparing highly aluminum-doped small-particle cobalt tetroxide according to claim 1, characterized in that: The calcination temperature is 650-750° C. and the calcination time is 5-7 hours.