High-aluminum-doped cobaltosic oxide precursor and preparation method and application thereof

Abstract

The invention provides a high-aluminum-doped cobaltosic oxide precursor and a preparation method and application thereof.The preparation method comprises the following steps that a cobalt-aluminum mixed salt solution, a precipitator solution and a complexing agent solution are introduced into a base solution, a co-precipitation reaction is conducted, and the high-aluminum-doped cobaltosic oxide precursor is obtained; the complexing agent solution comprises an imino complexing agent; the coprecipitation reaction comprises a seed crystal preparation stage and a crystal growth stage which are sequentially carried out. According to the preparation method, a large number of metal ions are complexed by adding the specific complexing agent and then are slowly released in the reaction process, so that the growth rate of crystals can be controlled, cobalt and aluminum can be uniformly precipitated, aluminum segregation is avoided, meanwhile, high aluminum doping can be achieved, the problem of uniformity in the aluminum doping process is solved, and the service life of the aluminum alloy is prolonged. Therefore, the performance of the lithium cobalt oxide battery prepared by taking the lithium cobalt oxide as the precursor is effectively improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of battery materials, and relates to a high-aluminum-doped tricobalt tetraoxide precursor and a preparation method and application thereof. BACKGROUND

[0002] With the continuous enrichment of functions of 3C electronic products such as mobile phones, notebook computers and digital cameras, the product power consumption increases significantly. Lithium cobalt oxide (LCO) materials are widely used in the above-mentioned devices due to their high specific capacity, good stability and high compaction density. With the increasing demand for lithium ion battery capacity of consumer electronic products, it is necessary to further increase the charging voltage of lithium cobalt oxide materials. The material properties of tricobalt tetraoxide, as a precursor material of lithium cobalt oxide cathode, greatly affect the performance of lithium cobalt oxide. In order to further improve the energy density of the battery, doping is one of the most widely studied technical solutions. Through doping elements, the anisotropic change of the structure can be inhibited, and the phase change of the layered LCO structure can be inhibited, the battery voltage can be improved, and the thermal stability of the material can be effectively improved, thereby improving the high-voltage cycle performance.

[0003] In order to improve the energy density of 3C batteries and at the same time provide stability at high voltage, doping in tricobalt tetraoxide precursor is an important development direction. In order to improve the high-voltage cycle performance of LCO materials, one effective method is aluminum doping. Doping aluminum in tricobalt tetraoxide can stabilize the structure, improve the cycle stability and thermal stability, and avoid the collapse of the crystal structure caused by irreversible phase change during charging and discharging. Therefore, by doping Al in the precursor in production, the high-voltage cycle performance of LCO materials can be indirectly enhanced, thereby meeting the strict requirements of high-performance 3C electronic products on battery materials.

[0004] In actual production process, the doping of high aluminum in tricobalt tetraoxide faces many challenges. In the process of preparing tricobalt tetraoxide, usually, liquid phase precipitation reaction is first used to prepare cobalt carbonate, and then centrifugal washing, drying and calcination process are carried out to obtain tricobalt tetraoxide. Although this process has the advantages of controllable process, easy synthesis and wide application in large-scale production, problems such as uneven doping process and Al segregation may occur when doping aluminum.

[0005] Therefore, the problems of morphology and uniformity control of these precursors have a significant adverse effect on the performance of the subsequent materials. Specifically, the unevenness of the doping elements in the precursor can cause regional differences in the performance of the material, which may make the doping substances in some regions more easily reduced or oxidized during heat treatment, resulting in different phases and properties in different regions, and further affecting the microstructure and macroscopic performance of the final material.

[0006] Based on the above research, solving the problem of uniformity of Al element doping in the preparation of cobalt tetraoxide is very important to improve the overall performance of LCO positive electrode material. SUMMARY

[0007] The present application aims to provide a high-aluminum-doped cobalt tetraoxide precursor, its preparation method and application. The preparation method adds a specific complexing agent to complex a large number of metal ions first, and then slowly releases them during the reaction process, thereby controlling the growth rate of the crystal, allowing uniform precipitation between cobalt and aluminum, avoiding aluminum segregation, and achieving high aluminum doping. The uniformity problem in the aluminum doping process is solved, and the performance of the lithium cobalt oxide battery prepared from the precursor is effectively improved.

[0008] To achieve this application, the following technical solutions are used:

[0009] In a first aspect, the present application provides a preparation method of a high-aluminum-doped cobalt tetraoxide precursor, which comprises the following steps:

[0010] The cobalt-aluminum mixed salt solution, the precipitant solution and the complexing agent solution are passed into the bottom solution to perform a co-precipitation reaction, thereby obtaining a high-aluminum-doped cobalt tetraoxide precursor.

[0011] The complexing agent solution comprises an imino complexing agent, and the co-precipitation reaction comprises a seed preparation stage and a crystal growth stage performed in sequence.

[0012] When the high-aluminum-doped cobalt tetraoxide precursor is prepared by precipitation, the imino complexing agent is added to complex a large number of metal ions, which exist in the system in the form of complex ions. During the reaction process, the metal ions are slowly released, so that the growth of the crystal is an orderly process, thereby controlling the growth rate of the crystal, allowing uniform precipitation between cobalt and aluminum, and improving the energy density and stability at high voltage of the lithium cobalt oxide battery. In addition, compared with conventional complexing agents (such as ammonia, citric acid, etc.), the imino complexing agent has higher stability in chemical structure and can maintain its binding ability with metal ions under harsh conditions. This allows them to maintain strong complexation in high temperature, high acid or alkalinity, or other adverse environments.

[0013] In addition, the co-precipitation process of the present application is divided into two stages: seed preparation and crystal growth. This not only avoids the occurrence of aluminum segregation, but also allows the preparation of large-particle high-aluminum-doped cobalt tetraoxide precursors.

[0014] It should be noted that the "high aluminum doping" in the high-aluminum-doped cobalt tetraoxide precursor of the present application refers to an aluminum doping amount of more than 10000ppm.

[0015] Preferably, the imino complexing agent comprises iminodiacetic acid and / or diiminodiacetic acid.

[0016] Preferably, the concentration of the imino complexing agent in the co-precipitation reaction system is 15-20 g / L, for example, it can be 15 g / L, 16 g / L, 17 g / L, 18 g / L, 19 g / L or 20 g / L, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0017] The concentration of the imino complexing agent in the co-precipitation reaction system of the present application will affect the crystal growth, thereby affecting the uniformity of the precipitation between cobalt and aluminum. If the concentration of the imino complexing agent in the reaction system is too low, the effect of the imino complexing agent will decrease, which will reduce the uniformity of the precipitation between cobalt and aluminum. If the concentration of the imino complexing agent in the reaction system is too high, it will lead to excessive chelation of metal ions, which is not conducive to the release of the metal ions during the reaction.

[0018] Preferably, in the cobalt-aluminum mixed salt solution, the concentration of cobalt ions is 90 g / L-150 g / L, for example, it can be 90 g / L, 110 g / L, 130 g / L or 150 g / L, and the concentration of aluminum ions is 1.5 g / L-2.0 g / L, for example, it can be 1.5 g / L, 1.7 g / L, 1.9 g / L or 2.0 g / L, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0019] Preferably, the precipitant solution comprises a carbonate solution with a concentration of 150 g / L-250 g / L, for example, it can be 150 g / L, 170 g / L, 190 g / L, 210 g / L, 230 g / L or 250 g / L, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0020] Preferably, in the seed preparation stage, the mass ratio of the cobalt-aluminum mixed salt solution to the precipitant solution is (0.3-0.4):1, for example, it can be 0.3:1, 0.32:1, 0.34:1, 0.36:1, 0.38:1 or 0.4:1, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0021] Preferably, in the crystal growth stage, the mass ratio of the cobalt-aluminum mixed salt solution to the precipitant solution is (0.1-0.15):1, for example, it can be 0.1:1, 0.11:1, 0.12:1, 0.13:1, 0.14:1 or 0.15:1, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0022] The application adopts different mass ratios of the cobalt-aluminum mixed salt solution and the precipitant solution in the seed crystal preparation stage and the crystal growth stage, can match different reaction stages, improve ion precipitation uniformity, and prevent ion segregation; if the mass ratio of the cobalt-aluminum mixed salt solution and the precipitant solution in the seed crystal preparation stage is too small, too many seed crystals are generated, if the mass ratio of the cobalt-aluminum mixed salt solution and the precipitant solution in the seed crystal preparation stage is too large, the generation of seed crystals is not conducive, if the mass ratio of the cobalt-aluminum mixed salt solution and the precipitant solution in the crystal growth stage is too small, small particles appear, and if the mass ratio of the cobalt-aluminum mixed salt solution and the precipitant solution in the crystal growth stage is too large, the particle morphology changes.

[0023] Preferably, in the seed crystal preparation stage, the pH of the reaction system is 8.5 or less, for example, it can be 8.5, 8.3, 8.1, 7.9, 7.7, 7.5 or 7.3, but is not limited to the listed values, other values not listed in the value range are also applicable, preferably 7.5-8.5.

[0024] Preferably, in the crystal growth stage, the pH of the reaction system is 7.7-8.2, for example, it can be 7.7, 7.9, 8.1 or 8.2, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0025] Preferably, the temperature of the seed crystal preparation stage is 40-45℃, for example, it can be 40℃, 41℃, 42℃, 43℃, 44℃ or 45℃, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0026] Preferably, the stirring speed of the seed crystal preparation stage is 300-350rpm, for example, it can be 300rpm, 310rpm, 320rpm, 330rpm, 340rpm or 350rpm, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0027] Preferably, the temperature of the crystal growth stage is 45-55℃, for example, it can be 45℃, 47℃, 49℃, 51℃, 53℃ or 55℃, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0028] Preferably, the stirring speed of the crystal growth stage is 250-280rpm, for example, it can be 250rpm, 260rpm, 270rpm or 280rpm, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0029] Preferably, the seed crystal prepared in the seed crystal preparation stage has a particle size D50 of 3-5 μm, for example, 3 μm, 4 μm or 5 μm, but not limited to the listed values, and other values not listed in the range are also applicable.

[0030] Preferably, the seed crystal prepared in the seed crystal preparation stage is put into another reactor for the crystal growth stage.

[0031] Preferably, the high-aluminum-doped cobaltosic oxide precursor has a particle size D50 of 15-17 μm, for example, 15 μm, 16 μm or 17 μm, but not limited to the listed values, and other values not listed in the range are also applicable.

[0032] Preferably, the high-aluminum-doped cobaltosic oxide precursor has an aluminum doping amount of 10,000-15,000 ppm, for example, 10,000 ppm, 11,000 ppm, 12,000 ppm, 13,000 ppm, 14,000 ppm or 15,000 ppm, but not limited to the listed values, and other values not listed in the range are also applicable.

[0033] In a second aspect, the present application provides a high-aluminum-doped cobaltosic oxide precursor prepared by the preparation method of the first aspect.

[0034] In a third aspect, the present application provides a high-aluminum-doped cobaltosic oxide prepared by calcining the high-aluminum-doped cobaltosic oxide precursor of the second aspect.

[0035] Preferably, the calcining comprises holding at a temperature of 300-500 °C, for example, 300 °C, 400 °C or 500 °C, for 0.5-1 h, for example, 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h or 1 h, and then holding at a temperature of 700-850 °C, for example, 700 °C, 750 °C, 800 °C or 850 °C, for 2-4 h, for example, 2 h, 2.5 h, 3 h, 3.5 h or 4 h, but not limited to the listed values, and other values not listed in the range are also applicable.

[0036] Preferably, the calcining is performed under compressed air at a flow rate of 2-5 L / min, for example, 2 L / min, 3 L / min, 4 L / min or 5 L / min, but not limited to the listed values, and other values not listed in the range are also applicable.

[0037] In a fourth aspect, the present application provides a lithium ion battery comprising a lithium cobaltate positive electrode material prepared from a lithium source and the high-aluminum-doped cobaltosic oxide of the third aspect.

[0038] Compared with the prior art, the present application has the following beneficial effects:

[0039] In the preparation of the high-aluminum-doped tricobalt tetraoxide precursor by precipitation, the present application adds imino complexing agent so that a large amount of metal ions are complexed, the metal ions exist in the system in the form of complex ions, and are slowly released during the reaction, so that the crystal growth is an orderly process, thereby controlling the crystal growth rate and enabling cobalt and aluminum to be uniformly precipitated, so as to improve the energy density and stability at high voltage of the lithium cobalt oxide battery and other performances. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 SEM image of the high-aluminum-doped tricobalt tetraoxide obtained by the preparation method described in Embodiment 1 of the present application.

[0041] Figure 2 Al element distribution map of the high-aluminum-doped tricobalt tetraoxide obtained by the preparation method described in Embodiment 1 of the present application. DETAILED DESCRIPTION

[0042] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations on the present application.

[0043] Embodiment 1

[0044] The present embodiment provides a preparation method of a high-aluminum-doped tricobalt tetraoxide precursor, which comprises the following steps:

[0045] (1) A cobalt-aluminum metal solution is configured, wherein the concentration of cobalt is 120 g / L and the concentration of aluminum is 1.8 g / L; an ammonium carbonate precipitant solution is configured, wherein the concentration of ammonium carbonate is 240 g / L;

[0046] (2) The reaction uses 25 g / L of ammonium carbonate solution as the bottom liquid, and then the cobalt-aluminum metal solution, the precipitant solution and the imino diacetic acid complexing agent solution are added in parallel flow to react, the concentration of imino diacetic acid in the reaction system is 18 g / L, the mixing is stirred at a speed of 320 rpm during the reaction, the mass ratio of the cobalt-aluminum metal solution to the precipitant solution is 0.35:1, the pH is adjusted to below 8.5, the reaction temperature is controlled at 43℃, and the reaction is continued until the particle size D50 of the cobalt carbonate reaches 4 μm as the crystal seed.

[0047] (3) Put a part of the above seed into a 25 g / L ammonium carbonate solution as a bottom liquid in a reaction kettle, and reduce the rotation speed to 270 rpm. The mass ratio of the cobalt-aluminum metal solution and the precipitant solution is controlled at 0.12:1. The pH is adjusted to be in the range of 8-8.2. The reaction temperature is controlled at 45℃ until the particle grows to 16 μm. Then, the temperature is gradually increased to 48℃ until the end of the reaction. After the end of the reaction, the cobalt carbonate slurry is obtained. After washing and drying, the high-aluminum-doped tricobalt tetraoxide precursor is obtained, wherein the aluminum doping amount is 11000 ppm.

[0048] The embodiment also provides a preparation method of the high-aluminum-doped tricobalt tetraoxide, and the preparation method comprises the following steps:

[0049] The high-aluminum-doped tricobalt tetraoxide precursor obtained in the embodiment is calcined in a rotary kiln. The calcining comprises the following steps: keeping the temperature at 400℃ for 0.8 h, and then keeping the temperature at 800℃ for 3 h. The flow rate of air during the calcining is 4 L / min. Finally, the high-aluminum-doped tricobalt tetraoxide is obtained.

[0050] The SEM image of the high-aluminum-doped tricobalt tetraoxide obtained in the embodiment is shown in Figure 1 The Al element distribution map is shown in Figure 2 From Figure 1 and Figure 2 It can be seen that the high-aluminum-doped tricobalt tetraoxide has high sphericity, and the aluminum element is uniformly distributed.

[0051] Example 2

[0052] The embodiment provides a preparation method of a high-aluminum-doped tricobalt tetraoxide precursor, and the preparation method comprises the following steps:

[0053] (1) A cobalt-aluminum metal solution is configured, wherein the concentration of cobalt is 150 g / L, and the concentration of aluminum is 2 g / L. An ammonium carbonate precipitant solution is configured, wherein the concentration of ammonium carbonate is 200 g / L.

[0054] (2) The reaction is carried out by using a 25 g / L ammonium carbonate solution as a bottom liquid, and then the cobalt-aluminum metal solution, the precipitant solution and the imino-diacetic acid complexing agent solution are added in parallel flow to react. The concentration of imino-diacetic acid in the reaction system is 20 g / L. The rotation speed is 350 rpm during the reaction. The mass ratio of the cobalt-aluminum metal solution and the precipitant solution is 0.3:1. The pH is adjusted to be below 8.5. The reaction temperature is controlled at 40℃. The reaction is carried out until the particle size D50 of the cobalt carbonate reaches 3 μm, which is used as a seed.

[0055] (3) A part of the above-mentioned seed crystal is put into a 25 g / L ammonium carbonate solution as a bottom liquid in a reaction kettle, the rotation speed is reduced to 280 rpm, the mass ratio of cobalt-aluminum metal solution and precipitant solution is controlled to be 0.1:1, the pH is adjusted to be 8.2-8.5, the reaction temperature is controlled to be 45°C until the particle grows to 15 μm, then the temperature is gradually increased to 55°C until the reaction is finished, after the reaction is finished, a cobalt carbonate slurry is obtained, after washing and drying, the high-aluminum-doped tricobalt tetroxide precursor is obtained, wherein the aluminum doping amount is 13000 ppm.

[0056] The embodiment also provides a preparation method of the high-aluminum-doped tricobalt tetroxide, and the preparation method comprises the following steps:

[0057] The high-aluminum-doped tricobalt tetroxide precursor obtained in the embodiment is calcined in a rotary kiln, the calcining comprises the following steps: keeping the temperature at 500°C for 0.5 h, then keeping the temperature at 700°C for 4 h, the flow rate of air during the calcining is 2 L / min, finally the high-aluminum-doped tricobalt tetroxide is obtained.

[0058] Embodiment 3

[0059] The embodiment provides a preparation method of a high-aluminum-doped tricobalt tetroxide precursor, and the preparation method comprises the following steps:

[0060] (1) A cobalt-aluminum metal solution is configured, wherein the concentration of cobalt is 100 g / L, and the concentration of aluminum is 1.5 g / L; an ammonium carbonate precipitant solution is configured, wherein the concentration of ammonium carbonate is 180 g / L;

[0061] (2) A reaction is performed by using a 25 g / L ammonium carbonate solution as a bottom liquid, then the cobalt-aluminum metal solution, the precipitant solution and the imino-diacetic acid complexing agent solution are added in parallel flow to perform the reaction, the concentration of imino-diacetic acid in the reaction system is 15 g / L, the mixing is stirred at a rotation speed of 300 rpm during the reaction, the mass ratio of the cobalt-aluminum metal solution and the precipitant solution is controlled to be 0.4:1, the pH is adjusted to be below 8.5, the reaction temperature is controlled to be 45°C, and the reaction is performed until the particle size D50 of the cobalt carbonate reaches 5 μm, as a seed crystal.

[0062] (3) A part of the above-mentioned seed crystal is put into a 25 g / L ammonium carbonate solution as a bottom liquid in a reaction kettle, and the cobalt-aluminum metal solution, the precipitant solution and the imino-diacetic acid complexing agent solution are added in parallel flow to perform the reaction, the rotation speed is reduced to 250 rpm, the mass ratio of the cobalt-aluminum metal solution and the precipitant solution is controlled to be 0.15:1, the pH is adjusted to be 8-8.2, the reaction temperature is controlled to be 40°C until the particle grows to 17 μm, then the temperature is gradually increased to 45°C until the reaction is finished, after the reaction is finished, a cobalt carbonate slurry is obtained, after washing and drying, the high-aluminum-doped tricobalt tetroxide precursor is obtained, wherein the aluminum doping amount is 15000 ppm.

[0063] The embodiment also provides a preparation method of the high-aluminum-doped tricobalt tetraoxide, and the preparation method comprises the following steps:

[0064] The high-aluminum-doped tricobalt tetraoxide precursor obtained in the embodiment is placed in a rotary kiln for calcination, the calcination comprises the following steps: keeping the temperature at 300 DEG C for 1 h, and then keeping the temperature at 850 DEG C for 2 h, the air flow rate is 5 L / min during the calcination, and finally the high-aluminum-doped tricobalt tetraoxide is obtained.

[0065] Embodiment 4

[0066] The embodiment provides a preparation method of a high-aluminum-doped tricobalt tetraoxide precursor, and the preparation method is same as that in the embodiment 1, with the exception that the concentration of iminodiacetic acid in the reaction system in the step (2) is 10 g / L.

[0067] The embodiment also provides a preparation method of the high-aluminum-doped tricobalt tetraoxide, and the preparation method is same as that in the embodiment 1, with the exception that the high-aluminum-doped tricobalt tetraoxide precursor obtained in the embodiment is used.

[0068] Embodiment 5

[0069] The embodiment provides a preparation method of a high-aluminum-doped tricobalt tetraoxide precursor, and the preparation method is same as that in the embodiment 1, with the exception that the concentration of iminodiacetic acid in the reaction system in the step (2) is 30 g / L.

[0070] The embodiment also provides a preparation method of the high-aluminum-doped tricobalt tetraoxide, and the preparation method is same as that in the embodiment 1, with the exception that the high-aluminum-doped tricobalt tetraoxide precursor obtained in the embodiment is used.

[0071] Embodiment 6

[0072] The embodiment provides a preparation method of a high-aluminum-doped tricobalt tetraoxide precursor, and the preparation method is same as that in the embodiment 1, with the exception that the mass ratio of the cobalt-aluminum metal solution and the precipitant solution is 0.2:1 when the seed crystal is prepared in the step (2).

[0073] The embodiment also provides a preparation method of the high-aluminum-doped tricobalt tetraoxide, and the preparation method is same as that in the embodiment 1, with the exception that the high-aluminum-doped tricobalt tetraoxide precursor obtained in the embodiment is used.

[0074] Embodiment 7

[0075] The embodiment provides a preparation method of a high-aluminum-doped tricobalt tetraoxide precursor, and the preparation method is same as that in the embodiment 1, with the exception that the mass ratio of the cobalt-aluminum metal solution and the precipitant solution is 0.5:1 when the seed crystal is prepared in the step (2).

[0076] The embodiment also provides a preparation method of high-aluminum-doped cobaltosic oxide, which is the same as that in the embodiment 1 except that the high-aluminum-doped cobaltosic oxide precursor obtained in the embodiment is used.

[0077] Embodiment 8

[0078] The embodiment provides a preparation method of high-aluminum-doped cobaltosic oxide precursor, which is the same as that in the embodiment 1 except that the mass ratio of the cobalt-aluminum metal solution to the precipitant solution is 0.25:1 during the crystal growth in step (3).

[0079] The embodiment also provides a preparation method of high-aluminum-doped cobaltosic oxide, which is the same as that in the embodiment 1 except that the high-aluminum-doped cobaltosic oxide precursor obtained in the embodiment is used.

[0080] Embodiment 9

[0081] The embodiment provides a preparation method of high-aluminum-doped cobaltosic oxide precursor, which is the same as that in the embodiment 1 except that the mass ratio of the cobalt-aluminum metal solution to the precipitant solution is 0.25:1 during the crystal growth in step (3).

[0082] The embodiment also provides a preparation method of high-aluminum-doped cobaltosic oxide, which is the same as that in the embodiment 1 except that the high-aluminum-doped cobaltosic oxide precursor obtained in the embodiment is used.

[0083] Comparative Example 1

[0084] The comparative example provides a preparation method of high-aluminum-doped cobaltosic oxide precursor, which is the same as that in the embodiment 1 except that the imino-diacetic acid complexing agent solution in step (2) is replaced by ammonia water, and the concentration of the imino-diacetic acid in the reaction system is replaced by ammonia water.

[0085] The comparative example also provides a preparation method of high-aluminum-doped cobaltosic oxide, which is the same as that in the embodiment 1 except that the high-aluminum-doped cobaltosic oxide precursor obtained in the comparative example is used.

[0086] The high-aluminum-doped cobaltosic oxide obtained in the above embodiments and comparative examples is mixed with lithium hydroxide and sintered to obtain a lithium cobaltate positive electrode material. The lithium cobaltate positive electrode material, a separator, a graphite negative electrode and an electrolyte are assembled to prepare a lithium cobaltate battery, and the electrochemical performance of the lithium cobaltate battery is tested. The test condition is that the lithium cobaltate battery is cycled for 200 cycles at a rate of 1C under a voltage of 2.4-4.6V at a normal temperature of 25℃.

[0087] The test results are shown in Table 1.

[0088] Table 1

[0089]

[0090] From Table 1, it can be seen that:

[0091] From Example 1 and Comparative Example 1, it can be seen that the imino complexing agent can complex a large amount of metal ions first, and then slowly release, so as to improve the uniformity of ion precipitation and the performance of the lithium cobalt oxide battery; from Example 1 and Examples 4-5, it can be seen that the concentration of the imino complexing agent in the co-precipitation reaction system of the present application will affect the uniformity of ion precipitation, and thus the performance of the lithium cobalt oxide battery; from Example 1 and Examples 6-9, it can be seen that the mass ratio of the cobalt-aluminum metal solution and the precipitant solution in the seed preparation stage and the crystal growth stage will affect the effect of the co-precipitation reaction, and thus the performance of the lithium cobalt oxide battery.

[0092] The above merely provides a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and those skilled in the art should understand that any change or replacement within the technical scope disclosed by the present application, which can be easily thought of by any person skilled in the art, falls within the protection scope and disclosure scope of the present application.

Claims

1. A method of preparing a high-aluminum tricobalt tetraoxide precursor, characterized by, The preparation method comprises the following steps: The cobalt-aluminum mixed salt solution, the precipitant solution and the complexing agent solution are fed into the bottom solution to perform a co-precipitation reaction to obtain a high-aluminum-doped tricobalt tetraoxide precursor; The complexing agent solution comprises an imino complexing agent; and the co-precipitation reaction comprises a seed preparation stage and a crystal growth stage performed in sequence.

2. The production method according to claim 1, characterized by, The imino complexing agent comprises iminodiacetic acid and / or diiminodiacetic acid; Preferably, the concentration of the imino complexing agent in the system of the co-precipitation reaction is 15-20 g / L; Preferably, in the cobalt-aluminum mixed salt solution, the concentration of cobalt ions is 90 g / L-150 g / L, and the concentration of aluminum ions is 1.5 g / L-2.0 g / L; Preferably, the precipitant solution comprises a carbonate solution with a concentration of 150 g / L-250 g / L.

3. The production method according to claim 1 or 2, characterized by, In the seed preparation stage, the mass ratio of the cobalt-aluminum mixed salt solution to the precipitant solution is (0.3-0.4):1; Preferably, in the crystal growth stage, the mass ratio of the cobalt-aluminum mixed salt solution to the precipitant solution is (0.1-0.15):1; Preferably, in the seed preparation stage, the pH of the reaction system is 8.5 or lower, preferably 7.5-8.5; Preferably, in the crystal growth stage, the pH of the reaction system is 7.7-8.

2.

4. The production method according to any one of claims 1 to 3, characterized by, The temperature of the seed preparation stage is 40℃-45℃; Preferably, the stirring speed of the seed preparation stage is 300 rpm-350 rpm; Preferably, the temperature of the crystal growth stage is 45℃-55℃; Preferably, the stirring speed of the crystal growth stage is 250 rpm-280 rpm.

5. The method of any one of claims 1-4, wherein, The particle size D50 of the seed obtained in the seed preparation stage is 3 μm-5 μm; Preferably, the seed obtained in the seed preparation stage is fed into another reaction kettle to perform the crystal growth stage.

6. The method of any one of claims 1-5, wherein, The particle size D50 of the high-aluminum-doped tricobalt tetraoxide precursor is 15 μm-17 μm; Preferably, the aluminum doping amount of the high-aluminum-doped tricobalt tetraoxide precursor is 10000-15000 ppm.

7. A high-aluminum-triposmium-tetroxide precursor, characterized in that, The high-aluminum-doped tricobalt tetraoxide precursor is prepared by the preparation method of any one of claims 1-6.

8. A high-aluminum-doped tricobalt tetraoxide characterized by, The high-aluminum-doped tricobalt tetraoxide is obtained by calcining the high-aluminum-doped tricobalt tetraoxide precursor of claim 7.

9. The high-aluminum-trioxide-cobalt of claim 8, wherein, The calcining comprises holding at a temperature of 300℃-500℃ for 0.5-1 h, and then holding at a temperature of 700℃-850℃ for 2-4 h; Preferably, the calcining is performed under compressed air with a flow rate of 2 L / min-5 L / min.

10. A lithium-ion battery, characterized by, The lithium ion battery comprises a lithium cobaltate positive electrode material prepared from a lithium source and the high-aluminum-doped tricobalt tetraoxide of claim 8 or 9.

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