Aluminum-doped cobalt tetroxide and preparation method thereof

Abstract

The present invention discloses a kind of aluminum-doped cobalt tetroxide and its preparation method, the preparation method comprises, mixing a cobalt salt solution, an aluminum salt solution, a precipitant solution, and a regulator solution to react, collecting insoluble matter; heat-treating the insoluble matter to obtain aluminum-doped cobalt tetroxide; wherein, the regulator in the regulator solution comprises at least one of D-glucosamine sulfate sodium salt and sodium benzoate. In the process of preparing aluminum-doped cobalt tetroxide by precipitation method, the present invention adds D-glucosamine sulfate sodium salt and sodium benzoate, effectively adjusting the micromorphology of aluminum-doped cobalt tetroxide, making the structure more uniform and the dispersibility better. At the same time, D-glucosamine sulfate sodium salt and sodium benzoate in a certain concentration range are also beneficial to improving the tap density of aluminum-doped cobalt tetroxide. Overall, the preparation method of the present invention is simple, the raw materials are easy to obtain, and it has good application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of cobalt tetroxide, and in particular to aluminum-doped cobalt tetroxide and a preparation method thereof. Background Art

[0002] The rapid development of electronic products has driven increased market demand for high-capacity, high-rate lithium-ion batteries. Lithium cobalt oxide is moving toward higher voltages, exceeding 4.5V. Higher voltages cause more lithium ions to escape from the crystal structure, severely impacting the material's structural stability and, in turn, the battery's cycling performance and safety. Cobalt tetroxide is the primary raw material for lithium cobalt oxide. As demand for lithium cobalt oxide's capacity and cycling performance increases, so too does the demand for cobalt tetroxide.

[0003] Aluminum doping can form aluminum-doped cobalt oxide crystals, which improve the conductivity and stability of lithium cobalt oxide electrode materials, thereby increasing the capacity and cycle life of batteries. Some studies have used liquid-phase precipitation to prepare aluminum-doped cobalt tetroxide. For example, CN108373175A discloses aluminum-doped cobalt tetroxide, its preparation method, and applications. A cobalt salt solution, a carbonate ion-containing precipitant solution, and a mixed solution of an aluminum salt and a complexing agent are co-precipitated to produce aluminum-doped cobalt carbonate, which is then calcined to produce aluminum-doped cobalt tetroxide. This method can successfully produce aluminum-doped cobalt tetroxide with relatively uniform, spherical particles. However, the feed rate of the raw materials is relatively slow, resulting in a long preparation cycle. CN114368792A discloses a method for preparing aluminum-doped cobalt tetroxide particles. A cobalt salt solution, an ammonium bicarbonate solution, and a sodium metaaluminate solution are reacted to produce cobalt carbonate, which is then calcined to produce cobalt tetroxide. This method can produce aluminum-doped cobalt tetroxide with a particle size of 14-17 μm and good uniformity. However, there are a large number of pores on the surface of aluminum-doped cobalt tetroxide, which has the disadvantage of low tap density. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a method for preparing aluminum-doped cobalt tetroxide, comprising:

[0005] Mixing a cobalt salt solution, an aluminum salt solution, a precipitant solution, and a regulator solution for reaction, and collecting insoluble matter;

[0006] The insoluble matter is heat-treated to obtain aluminum-doped cobalt tetroxide;

[0007] Wherein, the regulator in the regulator solution includes at least one of D-glucosamine sulfate sodium salt and sodium benzoate.

[0008] Furthermore, the regulator solution is a mixed solution of D-glucosamine sulfate sodium salt and sodium benzoate;

[0009] Wherein, the concentration of D-glucosamine sulfate sodium salt is 0.02-0.05 mol / L; the concentration of sodium benzoate is 0.01-0.03 mol / L.

[0010] Furthermore, the concentration of the cobalt salt in the cobalt salt solution is 110-150 g / L;

[0011] The concentration of aluminum salt in the aluminum salt solution is 1.2-1.6 g / L;

[0012] The concentration of the precipitant in the precipitant solution is 0.1-0.2 mol / L.

[0013] In the present invention, the types of cobalt salt, aluminum salt, and precipitant are not strictly limited. For example, the cobalt salt can be at least one of cobalt sulfate, cobalt chloride, and cobalt nitrate; the aluminum salt can be at least one of aluminum nitrate, aluminum chloride, aluminum sulfate, and sodium metaaluminate; and the precipitant can be at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium bicarbonate, sodium bicarbonate, and ammonium bicarbonate. The solvents for the cobalt salt solution, aluminum salt solution, and precipitant solution are not strictly limited and can be common solvents such as at least one of water, ethanol, and acetone, preferably water.

[0014] Furthermore, the cobalt salt solution, aluminum salt solution, precipitant solution, and regulator solution are mixed in a parallel flow manner at an inflow rate of 80-240 L / h.

[0015] Furthermore, the mixing reaction is carried out at a temperature of 60-100° C., a pH of 9-10, and a stirring speed of 200-400 rpm. During the mixing reaction, the reagent for adjusting the pH is not strictly limited, and illustratively can be sodium hydroxide, potassium hydroxide, or an aqueous solution thereof. If the pH is excessively adjusted, a small amount of inorganic acid or an aqueous solution of an inorganic acid is added. This is a conventional operation and can be adjusted as needed.

[0016] Furthermore, during the mixed reaction, 15-30m 3 Air is introduced at a flow rate of / h.

[0017] Furthermore, before collecting the insoluble matter, the method further includes observing the particle size of the intermediate obtained by the mixing reaction, and collecting the insoluble matter after the median particle size of the intermediate reaches the target value.

[0018] Furthermore, the heat treatment is continued at a temperature of 550-850° C. for 4-12 hours.

[0019] The present invention also provides aluminum-doped cobalt tetroxide, which is obtained by the above-mentioned preparation method.

[0020] The present invention also provides the use of the aluminum-doped cobalt tetroxide in lithium battery materials.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention adds D-glucosamine sulfate sodium salt and sodium benzoate during the precipitation process of preparing aluminum-doped cobalt tetroxide, effectively adjusting the micromorphology of the aluminum-doped cobalt tetroxide, making the structure more uniform and the dispersion better. At the same time, D-glucosamine sulfate sodium salt and sodium benzoate within a certain concentration range are also beneficial to improving the tap density of the aluminum-doped cobalt tetroxide. Overall, the preparation method of the present invention is simple, the raw materials are readily available, and it has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A flow chart showing the preparation method of aluminum-doped cobalt tetroxide according to the present invention is shown;

[0025] Figure 2 shows a scanning electron microscope image of aluminum-doped cobalt oxide prepared in Example 1;

[0026] Figure 3 shows a scanning electron microscope image of aluminum-doped cobalt oxide prepared in Example 2;

[0027] Figure 4 The scanning electron microscope image of aluminum-doped cobalt tetroxide prepared in Example 3 is shown;

[0028] Figure 5 The scanning electron microscope image of aluminum-doped cobalt tetroxide prepared in Comparative Example 3 is shown;

[0029] Figure 6 The scanning electron microscope image of the cobalt trioxide prepared in Comparative Example 4 is shown. DETAILED DESCRIPTION

[0030] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to form one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in the present invention.

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the specific embodiments of the present invention and the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] Example 1

[0033] like Figure 1 As shown, a method for preparing aluminum-doped cobalt tetroxide comprises the following steps:

[0034] S1. Prepare the reaction solution: prepare a 130 g / L cobalt chloride solution by mixing cobalt chloride and water; prepare a 1.5 g / L aluminum chloride solution by mixing aluminum chloride and water; prepare a 0.15 mol / L sodium hydroxide solution by mixing sodium hydroxide and water; prepare a 0.03 mol / L D-glucosamine sulfate sodium salt solution by mixing D-glucosamine sulfate sodium salt and water;

[0035] S2, precipitation reaction: cobalt chloride solution, aluminum chloride solution, sodium hydroxide solution, D-glucosamine sulfate sodium salt solution were injected into the reactor at the same time at the flow rate of 150L / h, 120L / h, 180L / h and 90L / h respectively. 3 / h, temperature 80°C, pH 9.5, and stirring speed 350 rpm for mixing and reacting. During the process, samples were taken every 2 hours to observe the particle size of the intermediate. When the median particle size of the intermediate was about 15 μm, the addition of the reaction solution was stopped, and the mixed system in the reactor was filtered and dried to obtain the insoluble matter;

[0036] S3. Heat treatment: heat the insoluble matter at 650°C for 8 hours to obtain aluminum-doped cobalt tetroxide.

[0037] Example 2

[0038] A method for preparing aluminum-doped cobalt tetroxide comprises the following steps:

[0039] S1. Prepare a reaction solution: prepare a 130 g / L cobalt chloride solution by mixing cobalt chloride and water; prepare a 1.5 g / L aluminum chloride solution by mixing aluminum chloride and water; prepare a 0.15 mol / L sodium hydroxide solution by mixing sodium hydroxide and water; and prepare a 0.03 mol / L sodium benzoate solution by mixing sodium benzoate and water.

[0040] S2, precipitation reaction: cobalt chloride solution, aluminum chloride solution, sodium hydroxide solution, sodium benzoate solution were injected into the reactor at the same time at the flow rate of 150L / h, 120L / h, 180L / h, and 90L / h respectively. 3 / h, temperature 80°C, pH 9.5, and stirring speed 350 rpm for mixing and reacting. During the process, samples were taken every 2 hours to observe the particle size of the intermediate. When the median particle size of the intermediate was about 15 μm, the addition of the reaction solution was stopped, and the mixed system in the reactor was filtered and dried to obtain the insoluble matter;

[0041] S3. Heat treatment: heat the insoluble matter at 650°C for 8 hours to obtain aluminum-doped cobalt tetroxide.

[0042] Example 3

[0043] A method for preparing aluminum-doped cobalt tetroxide comprises the following steps:

[0044] S1, prepare the reaction solution: cobalt chloride and water are mixed into 130g / L cobalt chloride solution; aluminum chloride and water are mixed into 1.5g / L aluminum chloride solution; sodium hydroxide and water are mixed into 0.15mol / L sodium hydroxide solution; D-glucosamine sulfate sodium salt, sodium benzoate and water are mixed into 0.02mol / L D-glucosamine sulfate sodium salt and 0.01mol / L sodium benzoate mixed solution;

[0045] S2, precipitation reaction: cobalt chloride solution, aluminum chloride solution, sodium hydroxide solution, D-glucosamine sulfate sodium salt and sodium benzoate mixed solution were injected into the reactor at the same time at the flow rate of 150L / h, 120L / h, 180L / h and 90L / h respectively. 3 / h, temperature 80°C, pH 9.5, and stirring speed 350 rpm for mixing and reacting. During the process, samples were taken every 2 hours to observe the particle size of the intermediate. When the median particle size of the intermediate was about 15 μm, the addition of the reaction solution was stopped, and the mixed system in the reactor was filtered and dried to obtain the insoluble matter;

[0046] S3. Heat treatment: heat the insoluble matter at 650°C for 8 hours to obtain aluminum-doped cobalt tetroxide.

[0047] Example 4

[0048] A method for preparing aluminum-doped cobalt oxide is basically the same as that of Example 3, except that: in step S1, D-glucosamine sulfate sodium salt, sodium benzoate and water are prepared into a mixed solution of 0.03 mol / L D-glucosamine sulfate sodium salt and 0.02 mol / L sodium benzoate.

[0049] Example 5

[0050] A preparation method of aluminum-doped cobalt tetroxide is basically the same as that of Example 3, except that: in step S1, D-glucosamine sulfate sodium salt, sodium benzoate and water are prepared into a mixed solution of 0.05 mol / L D-glucosamine sulfate sodium salt and 0.03 mol / L sodium benzoate.

[0051] Comparative Example 1

[0052] A method for preparing aluminum-doped cobalt oxide is basically the same as that in Example 3, except that: in step S1, D-glucosamine sulfate sodium salt, sodium benzoate and water are prepared into a mixed solution of 0.015 mol / L D-glucosamine sulfate sodium salt and 0.008 mol / L sodium benzoate.

[0053] Comparative Example 2

[0054] A method for preparing aluminum-doped cobalt oxide is basically the same as that of Example 3, except that: in step S1, D-glucosamine sulfate sodium salt, sodium benzoate and water are prepared into a mixed solution of 0.06 mol / L D-glucosamine sulfate sodium salt and 0.04 mol / L sodium benzoate.

[0055] Comparative Example 3

[0056] A method for preparing aluminum-doped cobalt tetroxide comprises the following steps:

[0057] S1. Prepare a reaction solution: prepare a 130 g / L cobalt chloride solution by mixing cobalt chloride and water; prepare a 1.5 g / L aluminum chloride solution by mixing aluminum chloride and water; and prepare a 0.15 mol / L sodium hydroxide solution by mixing sodium hydroxide and water.

[0058] S2, precipitation reaction: cobalt chloride solution, aluminum chloride solution, sodium hydroxide solution, respectively, at a flow rate of 150L / h, 120L / h, 180L / h into the reactor, under an air flow rate of 25m 3 / h, temperature 80°C, pH 9.5, and stirring speed 350 rpm for mixing and reacting. During the process, samples were taken every 2 hours to observe the particle size of the intermediate. When the median particle size of the intermediate was about 15 μm, the addition of the reaction solution was stopped, and the mixed system in the reactor was filtered and dried to obtain the insoluble matter;

[0059] S3. Heat treatment: heat the insoluble matter at 650°C for 8 hours to obtain aluminum-doped cobalt tetroxide.

[0060] Comparative Example 4

[0061] A method for preparing cobalt trioxide, comprising the following steps:

[0062] S1. Prepare a reaction solution: prepare a 130 g / L cobalt chloride solution by mixing cobalt chloride and water; prepare a 0.15 mol / L sodium hydroxide solution by mixing sodium hydroxide and water;

[0063] S2, precipitation reaction: Cobalt chloride solution and sodium hydroxide solution were injected into the reactor at a flow rate of 150L / h and 180L / h respectively. 3 / h, temperature 80°C, pH 9.5, and stirring speed 350 rpm for mixing and reacting. During the process, samples were taken every 2 hours to observe the particle size of the intermediate. When the median particle size of the intermediate was about 15 μm, the addition of the reaction solution was stopped, and the mixed system in the reactor was filtered and dried to obtain the insoluble matter;

[0064] S3. Heat treatment: keep the insoluble matter at 650°C for 8 hours to obtain cobalt tetroxide.

[0065] Test Case

[0066] The micromorphology of the materials prepared in Examples 1-3 of the present invention and Comparative Examples 3 and 4 was observed using a scanning electron microscope. The results are as follows: Figure 2-Figure 6 As shown. Because the median particle size of the intermediate is controlled, the cobalt oxide materials prepared in these examples and comparative examples have similar particle sizes. At the same time, the comparative example 4 without the introduction of aluminum has a more uniform and well-dispersed spherical structure. Compared with comparative example 4, the aluminum-doped cobalt oxide in comparative example 3 is broken. The aluminum element enters the reaction in the form of trivalent cations, while the cobalt element enters the reaction in the form of divalent cations. Since the precipitation rate of trivalent aluminum is higher than that of divalent cobalt, the distribution uniformity of the aluminum element is poor, and the distribution of aluminum in the intermediate is uneven, which leads to the collapse of the structure during calcination. The structures of Examples 1 and 2, which respectively introduce D-glucosamine sulfate sodium salt and sodium benzoate, are significantly improved compared to the structure of Comparative Example 3. This is because they can promote the dispersion of aluminum in the intermediate and improve the stability of the intermediate. It is worth noting that Example 3 with the addition of D-glucosamine sulfate sodium salt and sodium benzoate has good dispersibility, the breakage phenomenon has been significantly improved, and the structure is similar to that of Comparative Example 4. Examples 4 and 5 and Comparative Examples 1 and 2 have similar structures to Example 3 and are not described in detail here. These results indicate that the introduction of sodium D-glucosamine sulfate and sodium benzoate during the precipitation reaction can improve the stability and dispersibility of aluminum-doped cobalt oxide.

[0067] The tap density of the cobalt oxide materials prepared in the examples and comparative examples was also tested, and the results are shown in Table 1.

[0068] Table 1 Tap density results

[0069]

[0070] It can be seen from the test results in Table 1 that the present invention can effectively improve the tap density of the cobalt oxide material by introducing D-glucosamine sulfate sodium salt or sodium benzoate during the precipitation reaction. At the same time, when D-glucosamine sulfate sodium salt and sodium benzoate are introduced together, there is an optimal concentration, which can further improve the tap density.

[0071] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing aluminum-doped cobalt trioxide, characterized in that: include, Mixing a cobalt salt solution, an aluminum salt solution, a precipitant solution, and a regulator solution for reaction, and collecting insoluble matter; The insoluble matter is heat-treated to obtain aluminum-doped cobalt tetroxide; The regulator solution is a mixed solution of D-glucosamine sulfate sodium salt and sodium benzoate; Wherein, the concentration of D-glucosamine sulfate sodium salt is 0.02-0.05 mol / L; the concentration of sodium benzoate is 0.01-0.03 mol / L; The concentration of cobalt salt in the cobalt salt solution is 110-150 g / L; The concentration of aluminum salt in the aluminum salt solution is 1.2-1.6 g / L; The concentration of the precipitant in the precipitant solution is 0.1-0.2 mol / L; The mixing reaction is carried out at a temperature of 60-100° C., a pH of 9-10, and a stirring speed of 200-400 rpm.

2. The method for preparing aluminum-doped cobalt tetroxide according to claim 1, characterized in that: The cobalt salt solution, aluminum salt solution, precipitant solution and regulator solution are mixed in a parallel flow manner at an inflow rate of 80-240 L / h.

3. The method for preparing aluminum-doped cobalt trioxide according to claim 1, wherein: During the mixed reaction, 15-30m 3 Air is introduced at a flow rate of / h.

4. The method for preparing aluminum-doped cobalt tetroxide according to claim 1, wherein: Before collecting the insoluble matter, the method further includes observing the particle size of the intermediate obtained by the mixing reaction, and collecting the insoluble matter after the median particle size of the intermediate reaches the target value.

5. The method for preparing aluminum-doped cobalt tetroxide according to any one of claims 1 to 4, characterized in that: The heat treatment is carried out at a temperature of 550-850° C. for 4-12 hours.

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