Alpha-cobalt hydroxide and preparation method and application thereof

Abstract

The present disclosure provides an α-cobalt hydroxide and a preparation method and application thereof, wherein the preparation method comprises the following steps: (1) mixing a cobalt salt, an interlayer intercalation agent and a solvent to obtain a mixed solution; (2) injecting the mixed solution and liquid alkali into a bottom liquid in parallel to perform a coprecipitation reaction to obtain a cobalt hydroxide slurry; (3) separating the cobalt hydroxide slurry from solid and liquid, washing it with a detergent containing an interlayer intercalation agent, and drying it to obtain the α-cobalt hydroxide. The present disclosure can stably generate the structure of cobalt hydroxide by mixing a cobalt salt with an interlayer intercalation agent in advance and then performing a coprecipitation reaction with an alkali solution to avoid interlayer collapse, thereby obtaining a spherical α-cobalt hydroxide with good crystallinity and tight primary particle intercalation.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery materials and relates to α-cobalt hydroxide and a preparation method and application thereof. Background Art

[0002] With the popularization of mobile electronic devices and hybrid vehicles, the further development of lithium-ion batteries has been greatly promoted. Among them, lithium cobalt oxide has been widely used in the 3C market with its advantages such as stable structure, high specific capacity, and high voltage platform. However, when the cut-off voltage of lithium cobalt oxide is greater than 4.5V, the cathode will undergo a transformation from O3 phase to H1-3 phase. Although these phase changes are reversible, the transformation from ordered to disordered will greatly reduce the diffusion coefficient of Li+, resulting in a decrease in cycle performance and rate performance. At present, most lithium cobalt oxides on the market are prepared by solid-phase sintering. This method has high requirements for the precursor and needs to have good morphology and electrochemical properties. Cobalt hydroxide, as an important precursor for the synthesis of lithium cobalt oxide, can inherit its own structure well when mixed lithium is sintered into lithium cobalt oxide. The structure and morphology of the cobalt hydroxide precursor have an extremely important influence on the performance of lithium cobalt oxide. Among them, the cobalt hydroxide precursor has two crystal structures, α-type and β-type. The two structures are synthesized by different methods. Compared with the β-cobalt hydroxide with brucite structure, the α-cobalt hydroxide with hydrotalcite structure has a larger crystal plane spacing, which facilitates the flow of electrons and therefore has good electrical conductivity. After sintering into lithium cobalt oxide, its performance is better than that of β-cobalt hydroxide.

[0003] In the existing synthesis method, liquid alkali and cobalt metal liquid are usually used for direct precipitation. At the beginning of the reaction, the material presents green / light blue α-cobalt hydroxide, and the 001 crystal plane interlayer spacing is greater than 0.7nm. In the subsequent reaction process, due to the poor stability of α-cobalt hydroxide, the interlayer gradually collapses and gradually turns into pink β-cobalt hydroxide. The 001 crystal plane interlayer spacing decreases from 0.7nm to 0.46nm, the material activity decreases, and the performance after sintering into lithium cobalt oxide is lower than that of α-cobalt hydroxide. In addition, the sample without glucose is loosely inserted as a whole, and the TD is low; even if the newly generated α-cobalt hydroxide can be taken out in time at the beginning of the reaction, the material particle size at this moment is very small and the crystallinity is very poor, which is difficult to use to sinter lithium cobalt oxide positive electrode materials. Therefore, it is difficult to prepare stable and high-purity α-cobalt hydroxide directly by adding alkali precipitation.

[0004] CN112624206A discloses a method for preparing spherical α-cobalt hydroxide, which uses organic amine as a precipitant to prepare relatively stable spherical α-cobalt hydroxide, and does not require the addition of additional metal ions or complexing agents. The raw material components are simple and low in cost, and the organic amine can be recycled, reducing the production cost. However, the morphology of the synthetic sample is relatively loose, and the XRD crystallinity is poor, which has a bad effect on the performance of lithium cobalt oxide after sintering.

[0005] CN111559762A discloses a method for preparing cobalt hydroxide, comprising the following steps: (1) adding a cobalt salt solution and an ammonia solution to deionized water at 30 to 75° C., controlling the pH of the reaction system to be 6 to 9, and obtaining α-cobalt hydroxide, wherein the obtained α-cobalt hydroxide is very easily converted into a stable β-cobalt hydroxide, and the activity of the material will be significantly reduced.

[0006] The α-cobalt hydroxide obtained by the method described in the above scheme has a loose morphology or poor stability, and it is difficult to obtain a lithium cobalt oxide positive electrode material with excellent performance. Summary of the invention

[0007] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0008] The purpose of the present invention is to provide an α-cobalt hydroxide and a preparation method and application thereof. The present invention can stably generate the structure of cobalt hydroxide by mixing a cobalt salt with an interlayer intercalation agent in advance and then performing a coprecipitation reaction with an alkali solution, thereby avoiding interlayer collapse and obtaining a spherical α-cobalt hydroxide with intact crystallinity and tightly intercalated primary particles.

[0009] To achieve this purpose, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present disclosure provides a method for preparing α-cobalt hydroxide, the preparation method comprising the following steps:

[0011] (1) mixing a cobalt salt, an interlayer intercalation agent and a solvent to obtain a mixed solution;

[0012] (2) injecting the mixed solution and liquid caustic soda into the bottom liquid in parallel to carry out a coprecipitation reaction to obtain a cobalt hydroxide slurry;

[0013] (3) The cobalt hydroxide slurry is separated into solid and liquid, washed with a detergent containing an intercalation agent, and dried to obtain the α-cobalt hydroxide.

[0014] The present invention uses liquid alkali and cobalt metal liquid for precipitation, and adds an interlayer intercalator to the cobalt salt solution to form a sheet-intercalated spherical morphology of cobalt hydroxide. The diameter of the interlayer intercalator is about 0.3nm, and it can be used as an interlayer intercalator to be intercalated between the uncollapsed α-cobalt hydroxide layers, and the hydroxyl groups on both sides of the interlayer intercalator can form hydrogen bonds with the hydroxyl groups of cobalt hydroxide, making the α-cobalt hydroxide structure more stable, thereby obtaining a spherical α-cobalt hydroxide with intact crystallinity and tightly intercalated primary particles. Using a detergent containing an interlayer intercalator can not only avoid the oxidation of cobalt hydroxide, but also further maintain the stability of α-cobalt hydroxide, thereby inhibiting the phase transition of α-cobalt hydroxide at the root.

[0015] In one embodiment, the cobalt salt in step (1) includes any one of cobalt chloride, cobalt sulfate or cobalt nitrate, or a combination of at least two thereof.

[0016] In one embodiment, the intercalator comprises glucose.

[0017] The present invention uses glucose as an interlayer intercalator. The molecular size of the glucose is suitable and can be perfectly embedded in the interlayer of α-cobalt hydroxide to play a supporting structure role. The hydroxyl groups of the glucose molecules can form hydrogen bonds with the hydroxyl groups of the interlayer of α-cobalt hydroxide to further stabilize the structure.

[0018] In one embodiment, the concentration of the cobalt salt in the mixed solution is 90-130 g / L, for example, 90 g / L, 100 g / L, 110 g / L, 120 g / L or 130 g / L.

[0019] In one embodiment, the concentration of the intercalant in the mixed solution is 0.5-2 g / L, for example, 0.5 g / L, 0.8 g / L, 1 g / L, 1.5 g / L or 2 g / L.

[0020] In one embodiment, the concentration of the alkali solution in step (2) is 100-400 g / L, for example, 100 g / L, 150 g / L, 200 g / L, 300 g / L or 400 g / L.

[0021] In one embodiment, the base solution comprises sodium hydroxide.

[0022] In one embodiment, the pH of the base solution is 9.5-10.5, for example, 9.5, 9.8, 10, 10.2 or 10.5.

[0023] In one embodiment, the temperature of the base liquid is 40-50°C, for example, 40°C, 42°C, 45°C, 48°C or 50°C.

[0024] In one embodiment, the stirring speed of the coprecipitation reaction in step (2) is 200-500 rpm, for example, 200 rpm, 250 rpm, 300 rpm, 400 rpm or 500 rpm.

[0025] In one embodiment, the atmosphere of the coprecipitation reaction includes nitrogen.

[0026] In one embodiment, the flow rate of the nitrogen is 10 to 20 L / min, for example, 10 L / min, 12 L / min, 15 L / min, 18 L / min or 20 L / min.

[0027] In one embodiment, the pH of the coprecipitation reaction in step (2) is 8 to 9, for example, 8, 8.2, 8.5, 8.8 or 9.

[0028] In one embodiment, the end point of the coprecipitation reaction is that the particle size of the particles in the system is 5 to 22 μm, for example, 5 μm, 8 μm, 10 μm, 15 μm or 22 μm.

[0029] In one embodiment, the concentration of the intercalant in the detergent in step (3) is 0.05-1 g / L, for example, 0.05 g / L, 0.08 g / L, 0.1 g / L, 0.5 g / L or 1 g / L.

[0030] In one embodiment, the volume ratio of the detergent to the cobalt hydroxide slurry is (0.5-1.5):1, for example: 0.5:1, 0.8:1, 1:1, 1.2:1 or 1.5:1, etc.

[0031] In one embodiment, the drying equipment in step (3) comprises any one of a vacuum oven, a nitrogen furnace or a muffle furnace, or a combination of at least two of them.

[0032] In one embodiment, the drying temperature is 100-120°C, for example, 100°C, 105°C, 110°C, 115°C or 120°C.

[0033] In one embodiment, the drying time is 16 to 20 hours, for example, 16 hours, 17 hours, 18 hours, 19 hours or 20 hours.

[0034] In one embodiment, the drying is followed by screening.

[0035] In one embodiment, the mesh size of the sieve is 200-400 meshes, for example, 200 meshes, 250 meshes, 300 meshes, 350 meshes or 400 meshes.

[0036] In a second aspect, the present disclosure provides an α-cobalt hydroxide, which is prepared by the method described in the first aspect.

[0037] The α-cobalt hydroxide prepared by the method disclosed in the present invention is spherical, and the crystallinity of the α-cobalt hydroxide is intact, and the primary particles are tightly embedded.

[0038] In a third aspect, the present disclosure provides a lithium cobalt oxide, which is prepared by mixing and sintering the α-cobalt hydroxide described in the second aspect and a lithium source.

[0039] In a fourth aspect, the present disclosure provides a lithium-ion battery, wherein the lithium-ion battery comprises the lithium cobalt oxide as described in the third aspect.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The present invention adds glucose as an interlayer intercalator. Benefiting from its appropriate molecular size (0.3 nm), it can be perfectly embedded in the interlayer of α-cobalt hydroxide to play a role in supporting the structure. The hydroxyl groups of the glucose molecules can form hydrogen bonds with the hydroxyl groups between the α-cobalt hydroxide layers, further stabilizing the structure and avoiding interlayer collapse. During the washing process, the glucose solution is used again as a detergent, which can not only avoid the oxidation of cobalt hydroxide, but also further maintain the stability of α-cobalt hydroxide, thereby fundamentally inhibiting the phase transition of α-cobalt hydroxide, and finally obtaining spherical α-cobalt hydroxide with intact crystallinity and tightly intercalated primary particles.

[0042] (2) The first-week discharge specific capacity of the cobalt oxide lithium battery made using the α-cobalt hydroxide disclosed in the present invention can reach more than 194.9 mAh / g, and the capacity retention rate of 25 cycles at 1C can reach more than 87.2%.

[0043] Other aspects will be apparent upon reading and understanding the drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings are used to provide further understanding of the technical solution of this article and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of this article and do not constitute a limitation on the technical solution of this article.

[0045] Figure 1 This is a SEM image of α-cobalt hydroxide obtained in Example 1.

[0046] Figure 2 This is a SEM image of α-cobalt hydroxide obtained in Example 2.

[0047] Figure 3 This is a SEM image of α-cobalt hydroxide obtained in Example 3.

[0048] Figure 4 This is the SEM image of cobalt hydroxide obtained in Comparative Example 1.

[0049] Figure 5 This is the SEM image of cobalt hydroxide obtained in Comparative Example 2.

[0050] Figure 6 XRD comparison diagram of cobalt hydroxide obtained in Example 1-3 and Comparative Example 1-2. DETAILED DESCRIPTION

[0051] The technical solution of the present disclosure is further described below through specific implementation methods. Those skilled in the art should understand that the embodiments are only to help understand the present disclosure and should not be regarded as specific limitations of the present disclosure.

[0052] Example 1

[0053] This embodiment provides an α-cobalt hydroxide, which is prepared by the following method:

[0054] (1) mixing cobalt chloride, glucose and water to obtain a mixed solution having a cobalt chloride concentration of 130 g / L and a glucose concentration of 0.5 g / L;

[0055] (2) Add 250 L of pure water to a 500 L reactor until the reactor is half full, start stirring at the same time, the speed is 400 rpm, turn on nitrogen, adjust the flow rate to 10 L / min, adjust the pH of the bottom liquid to 10, and adjust the bottom liquid temperature to 45 ° C., and inject the mixed solution and 300 g / L of liquid alkali into the reactor in parallel, keep the reaction pH at 8.5, start suction filtration after the reactor is full, keep the reactor liquid level near the overflow port, and stop feeding the liquid until the particle size grows to 20 μm, to obtain cobalt hydroxide slurry;

[0056] (3) The cobalt hydroxide slurry is centrifuged and washed, the detergent is a glucose solution with a concentration of 0.05 g / L (the volume ratio of the detergent to the cobalt hydroxide slurry is 1:1), and dried in a blast oven at 110° C. for 16 h. The dried material is sieved on a 300-mesh sieve to obtain the α-cobalt hydroxide.

[0057] The SEM image of the α-cobalt hydroxide is as follows Figure 1 shown.

[0058] Example 2

[0059] This embodiment provides an α-cobalt hydroxide, which is prepared by the following method:

[0060] (1) mixing cobalt chloride, glucose and water to obtain a mixed solution having a cobalt chloride concentration of 90 g / L and a glucose concentration of 1 g / L;

[0061] (2) Add 250 L of pure water to a 500 L reactor until the reactor is half full, start stirring at the same time, the speed is 200 rpm, turn on nitrogen, adjust the flow rate to 10 L / min, adjust the pH of the bottom liquid to 9.5, and adjust the bottom liquid temperature to 40° C., inject the mixed solution and 100 g / L of liquid alkali into the reactor in parallel, keep the reaction pH at 8, start suction filtration after the reactor is full, keep the reactor liquid level near the overflow port, and stop adding liquid until the particle size grows to 5 μm, to obtain cobalt hydroxide slurry;

[0062] (3) The cobalt hydroxide slurry is centrifuged and washed, the detergent is a glucose solution with a concentration of 0.1 g / L (the volume ratio of the detergent to the cobalt hydroxide slurry is 1.5:1), and dried in a blast oven at 100° C. for 20 h. The dried material is sieved on a 200-mesh sieve to obtain the α-cobalt hydroxide.

[0063] The SEM image of the α-cobalt hydroxide is as follows Figure 2 shown.

[0064] Example 3

[0065] This embodiment provides an α-cobalt hydroxide, which is prepared by the following method:

[0066] (1) mixing cobalt chloride, glucose and water to obtain a mixed solution having a cobalt chloride concentration of 110 g / L and a glucose concentration of 2 g / L;

[0067] (2) Add 250 L of pure water to a 500 L reactor until the reactor is half full, start stirring at the same time, the speed is 500 rpm, turn on nitrogen, adjust the flow rate to 20 L / min, adjust the pH of the bottom liquid to 10.5, and adjust the bottom liquid temperature to 50° C., inject the mixed solution and 300 g / L of liquid alkali into the reactor in parallel, keep the reaction pH at 9.5, start suction filtration after the reactor is full, keep the reactor liquid level near the overflow port, and stop feeding the liquid until the particle size grows to 22 μm, to obtain cobalt hydroxide slurry;

[0068] (3) The cobalt hydroxide slurry is centrifuged and washed, the detergent is a glucose solution with a concentration of 1 g / L (the volume ratio of the detergent to the cobalt hydroxide slurry is 1.5:1), and dried in a blast oven at 120° C. for 16 h. The dried material is sieved on a 400-mesh sieve to obtain the α-cobalt hydroxide.

[0069] The SEM image of the α-cobalt hydroxide is as follows Figure 3 shown.

[0070] Example 4

[0071] The only difference between this embodiment and embodiment 1 is that the concentration of the intercalating agent (glucose) in the mixed solution is 0.1 g / L, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0072] Example 5

[0073] The only difference between this embodiment and embodiment 1 is that the concentration of the intercalating agent (glucose) in the mixed solution is 3 g / L, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0074] Example 6

[0075] The only difference between this embodiment and embodiment 1 is that the concentration of glucose in the detergent in step (3) is 0.01 g / L, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0076] Example 7

[0077] The only difference between this embodiment and embodiment 1 is that the concentration of glucose in the detergent in step (3) is 2 g / L, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0078] Comparative Example 1

[0079] The only difference between this comparative example and Example 1 is that glucose is not added in step (1), and the other conditions and parameters are exactly the same as those in Example 1.

[0080] The SEM image of the obtained cobalt hydroxide is as follows Figure 4 shown.

[0081] Comparative Example 2

[0082] The only difference between this comparative example and Example 1 is that the detergent used in step (3) is deionized water, and the other conditions and parameters are exactly the same as those in Example 1.

[0083] The SEM image of the obtained cobalt hydroxide is as follows Figure 5 shown.

[0084] Comparative Example 3

[0085] The only difference between this comparative example and Example 1 is that glucose is injected into the bottom liquid in the form of a solution together with the cobalt salt solution and the liquid alkali, and the other conditions and parameters are exactly the same as those in Example 1.

[0086] Performance Test:

[0087] 50 kg of cobalt hydroxide prepared in the embodiment and the comparative example was mixed with one equivalent of lithium carbonate in a three-dimensional mixer for 30 min. The mixed material was placed in a box furnace for sintering at a sintering temperature of 800 degrees for 10 h. After sintering, it was naturally cooled and sieved with a 300-mesh sieve to obtain lithium cobalt oxide. The sintered lithium cobalt oxide material was used as the positive electrode and the lithium sheet as the negative electrode to assemble a button battery. The first week charge and discharge capacity was tested at a current density of 0.1C on a blue electric test cabinet, and the capacity retention rate at a current density of 1C was tested. The test results are shown in Table 1:

[0088] Table 1

[0089]

[0090]

[0091] As can be seen from Table 1, from Examples 1-3, the first-week discharge specific capacity of the cobalt oxide battery made using the α-cobalt hydroxide disclosed in the present invention can reach more than 194.9 mAh / g, and the capacity retention rate of 25 cycles at 1C can reach more than 87.2%.

[0092] By comparing Example 1 with Examples 4-5, it can be seen that in the preparation process of α-cobalt hydroxide described in the present disclosure, the concentration of the interlayer intercalant in the mixed solution will affect its structure and thus affect its performance. The concentration of the interlayer intercalant in the mixed solution is controlled at 0.5-2 g / L, and the α-cobalt hydroxide obtained has excellent structure and good performance. If the concentration of the interlayer intercalant in the mixed solution is too high, it will have little effect on the electrochemical properties of the product, but will cause the concentration of organic matter in the reaction system to be too high, increase the cost of wastewater treatment, and cause waste of raw materials. If the concentration of the interlayer intercalant in the mixed solution is too low, it will lead to incomplete interlayer intercalation, deviation in the interlayer spacing, and reduced product performance.

[0093] By comparing Example 1 with Examples 6-7, it can be seen that in the preparation process of α-cobalt hydroxide described in the present disclosure, the concentration of the interlayer intercalant in the detergent will affect its structure and thus affect its performance. The concentration of the interlayer intercalant in the detergent is controlled at 0.05-1 g / L, and the α-cobalt hydroxide obtained has excellent structure and good performance. If the concentration of the interlayer intercalant in the detergent is too high, it will have little effect on the electrochemical properties of the product, but will cause the concentration of organic matter in the washing wastewater to be too high, increase the cost of wastewater treatment, and cause waste of raw materials. If the concentration of the interlayer intercalant in the detergent is too low, some materials will not be able to stably maintain the α-cobalt hydroxide structure, and will be converted into β-cobalt hydroxide during the washing process, thereby affecting product performance.

[0094] By comparing Example 1 and Comparative Example 1, it can be seen that the present invention uses liquid alkali and cobalt metal liquid for precipitation, and adding an interlayer intercalator to the cobalt salt solution can make cobalt hydroxide form a sheet-intercalated spherical morphology. The diameter of the interlayer intercalator is about 0.3 nm, and it can be used as an interlayer intercalator to be intercalated between the uncollapsed α-cobalt hydroxide layers, and the hydroxyl groups on both sides of the interlayer intercalator can form hydrogen bonds with the hydroxyl groups of the cobalt hydroxide, so that the α-cobalt hydroxide structure is more stable, thereby obtaining a spherical α-cobalt hydroxide with intact crystallinity and tight primary particle intercalation.

[0095] From the comparison between Example 1 and Comparative Example 2, it can be seen that the use of a detergent containing an intercalating agent can not only prevent the oxidation of cobalt hydroxide, but also further maintain the stability of α-cobalt hydroxide, thereby fundamentally inhibiting the phase transformation of α-cobalt hydroxide.

[0096] By comparing Example 1 and Comparative Example 3, it can be seen that the present invention pre-mixes the cobalt salt and the interlayer intercalator to prepare a mixed solution and then feeds it, and the electrochemical performance is significantly better than the separate liquid feeding method. This is mainly because the uniformity of the intercalator in the reaction system cannot be guaranteed when the liquid is fed separately, resulting in a significant decrease in the effect of the interlayer intercalator and a decrease in product performance.

[0097] The SEM images of cobalt hydroxide obtained in Examples 1-3 and Comparative Examples 1-2 are as follows: Figure 1-5 As shown, the XRD comparison diagram of cobalt hydroxide obtained in Example 1-3 and Comparative Example 1-2 is as follows Figure 6 As shown by Figure 1-3 It can be seen that as the glucose concentration increases, the spherical particles are more closely intercalated and the binding Figure 6 It can be seen that Examples 1-3 of the present disclosure are all high-purity α-cobalt hydroxides with narrow half-peak width and high peak intensity, indicating that the present disclosure can obtain spherical α-cobalt hydroxides with good crystallinity and relatively dense primary particle intercalation by adding an interlayer intercalation agent. Figure 1-3 and Figure 4-5 Contrast, combine Figure 6 It can be seen that in comparative example 1, glucose is not used during the liquid feeding process. It can be seen from SEM that when glucose is not used, the spherical particles are very loosely intercalated. In comparative example 2, glucose is not added during the washing process, and a large number of newly generated primary particles exist on the surface of the sample, indicating that when the washing water does not contain glucose, the structure will be reorganized and transformed from α-cobalt hydroxide to β-cobalt hydroxide.

Claims

1. A method for preparing α-cobalt hydroxide, comprising the following steps: (1) mixing a cobalt salt, an interlayer intercalation agent and a solvent to obtain a mixed solution; (2) injecting the mixed solution and liquid caustic soda into the bottom liquid in parallel to carry out a coprecipitation reaction to obtain a cobalt hydroxide slurry; (3) separating the cobalt hydroxide slurry into solid and liquid, washing it with a detergent containing an intercalation agent, and drying it to obtain the α-cobalt hydroxide; The intercalator includes glucose.

2. The preparation method according to claim 1, wherein The cobalt salt in step (1) includes any one of cobalt chloride, cobalt sulfate or cobalt nitrate, or a combination of at least two of them.

3. The preparation method according to claim 1, wherein The concentration of the cobalt salt in the mixed solution of step (1) is 90-130 g / L.

4. The preparation method according to claim 1, wherein The concentration of the intercalation agent in the mixed solution of step (1) is 0.5-2 g / L.

5. The preparation method according to claim 1, wherein The base liquid in step (2) comprises sodium hydroxide.

6. The preparation method according to claim 1, wherein The pH of the base solution in step (2) is 9.5 to 10.

5.

7. The preparation method according to claim 1, wherein The temperature of the base liquid in step (2) is 40-50°C.

8. The preparation method according to claim 1, wherein The stirring speed of the coprecipitation reaction in step (2) is 200 to 500 rpm.

9. The preparation method according to claim 1, wherein The atmosphere of the coprecipitation reaction in step (2) includes nitrogen.

10. The preparation method according to claim 9, wherein The flow rate of the nitrogen is 10-20 L / min.

11. The preparation method according to claim 1, wherein The pH of the coprecipitation reaction in step (2) is 8-9.

12. The preparation method according to claim 11, wherein The end point of the coprecipitation reaction is that the particle size of the particles in the system is 5 to 22 μm.

13. The preparation method according to claim 1, wherein The concentration of the intercalating agent in the detergent of step (3) is 0.05-1 g / L.

14. The preparation method according to claim 1, wherein The volume ratio of the detergent to the cobalt hydroxide slurry is (0.5-1.5):

1.

15. The preparation method according to claim 1, wherein: The drying equipment in step (3) includes any one of a vacuum oven, a nitrogen furnace or a muffle furnace, or a combination of at least two of them.

16. The preparation method according to claim 1, wherein: The drying temperature is 100-120°C.

17. The preparation method according to claim 1, wherein The drying time is 16 to 20 hours.

18. The preparation method according to claim 1, wherein: The drying is followed by sieving.

19. The preparation method according to claim 18, wherein: The mesh number of the sieving screen is 200 to 400 meshes.

20. An α-cobalt hydroxide obtained by the method according to any one of claims 1 to 19.

21. Lithium cobalt oxide prepared by mixing and sintering the α-cobalt hydroxide as claimed in claim 20 and a lithium source.

22. A lithium ion battery comprising the lithium cobalt oxide according to claim 21.

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