A lithium-rich manganese-based precursor material, a preparation method and application thereof

Abstract

The application provides a lithium-rich manganese-based precursor material and a preparation method and application thereof, and the preparation method comprises the following steps: mixing a nickel-cobalt-manganese mixed salt solution, a precipitant solution and a complexing agent solution under a protective gas atmosphere, performing a co-precipitation reaction, starting to pass in an oxygen-containing gas when the co-precipitation reaction reaches a particle growth stage, and then continuing to perform the co-precipitation reaction to obtain the lithium-rich manganese-based precursor material. The preparation method introduces an oxidizing atmosphere in the growth stage of the precursor material, avoids the problems of close particle growth, easy agglomeration and poor morphology in the preparation process of the existing lithium-rich manganese precursor material, and obtains a lithium-rich manganese-based precursor material with high dispersity and high specific surface.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of battery materials, and relates to a lithium-rich manganese-based precursor material and a preparation method and application thereof. BACKGROUND

[0002] In recent years, lithium ion batteries have achieved great commercial success in the field of portable electronic products and are also the main energy storage equipment of electric vehicles. Lithium-rich manganese-based positive electrode materials are considered to be positive electrode materials with good application prospects due to their high specific capacity (>250 mAh g -1 ) and low cost.

[0003] Currently, the preparation of lithium-rich manganese precursors for industrialization mainly adopts the method of hydroxide co-precipitation, specifically, a mixed salt solution of nickel, cobalt and manganese, a hydroxide precipitant and a complexing agent are mixed and then put into a reaction kettle with a bottom liquid and a protective gas for constant-temperature co-precipitation. After the reaction, the overflowed material is subjected to solid-liquid separation, aging, centrifugation and drying to obtain a spherical lithium-rich manganese precursor material. However, as the manganese content increases, the agglomeration of small-particle nickel-cobalt-manganese hydroxide becomes serious, the morphology uniformity becomes poor, and the specific surface area and physicochemical properties of the precursor become poor.

[0004] For example, CN 110323430A discloses a preparation method of a lithium-rich manganese-based material and the lithium-rich manganese-based material. The preparation method comprises mixing a mixed metal salt solution of Mn 2+ and M 2+ , a complexing agent, a precipitant and a reducing agent to prepare a lithium-rich manganese precursor. By controlling the concentration of the reducing agent, a lithium-rich manganese-based material with better electrochemical performance is prepared. However, as the manganese content increases in the co-precipitation process of the lithium-rich manganese-based precursor, the particles grow more closely and agglomerate seriously. The overall morphology of the precursor is difficult to control, the sphericity and dispersity are poor, and the structure of the positive electrode material sintered subsequently is unstable, and the cycle performance is poor.

[0005] For another example, CN 116216796A discloses a modified nickel-manganese binary precursor and a preparation method and application thereof. The preparation method pre-adds a modifier to the reaction bottom liquid to control the crystal form of the binary nickel-manganese precursor. The obtained nickel-manganese hydroxide has a relatively dense primary crystal form. Although the preparation method avoids the problems of easy precipitation of trimanganese tetraoxide and loose morphology of the primary crystal form in the existing preparation method of the nickel-manganese binary precursor, as the manganese content increases in the co-precipitation process of the lithium-rich manganese-based precursor, the particles grow more closely and agglomerate seriously. The overall morphology of the precursor obtained by the preparation method is difficult to control, the sphericity and dispersity are poor, and the preparation method is not conducive to the sintering of the subsequent positive electrode material.

[0006] Based on the above research, it is necessary to provide a preparation method of a lithium-rich manganese-based precursor material, which can solve the problems of particle agglomeration, poor dispersibility and difficult to control morphology caused by the increase of manganese content during co-precipitation. SUMMARY

[0007] The purpose of the present application is to provide a lithium-rich manganese-based precursor material and its preparation method and application. The preparation method introduces an oxidizing atmosphere during the growth stage of the precursor material, avoiding the problems of tight particle growth, easy agglomeration and poor morphology in the preparation process of existing lithium-rich manganese precursor materials, and obtaining a lithium-rich manganese-based precursor material with high dispersibility and high specific surface area.

[0008] To achieve this purpose of the application, the following technical solutions are adopted:

[0009] In a first aspect, the present application provides a preparation method of a lithium-rich manganese-based precursor material, which comprises the following steps:

[0010] Under a protective gas atmosphere, a nickel-cobalt-manganese mixed salt solution, a precipitant solution and a complexing agent solution are mixed to perform a co-precipitation reaction. When the co-precipitation reaction enters the growth stage of the particles, oxygen-containing gas is started to be introduced, and then the co-precipitation reaction is continued to obtain the lithium-rich manganese-based precursor material.

[0011] In order to avoid the problem of particle agglomeration caused by the increase of manganese content during the preparation of a lithium-rich manganese-based precursor by co-precipitation, on the basis of co-precipitation in a protective gas atmosphere, oxygen-containing gas is started to be introduced when the particles enter the growth stage after nucleation, so that the system is slightly oxidized, and the particles grow in the protective gas and oxygen-containing gas (in the co-precipitation reaction stage of the present application, the protective gas is always kept to be introduced). This avoids particle agglomeration, and the preparation method of the present application is simple and low in cost, only needs to add a three-way joint at the gas inlet to introduce an oxygen atmosphere, without the need to modify and add the gas inlet pipeline of the existing kettle body.

[0012] Preferably, the co-precipitation reaction is continued for 2-10h, for example, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h, and then the oxygen-containing gas is started to be introduced.

[0013] In the present application, the oxygen-containing gas is started to be introduced at a specific time during the co-precipitation reaction. If the oxygen-containing gas is introduced too late, the lithium-rich manganese precursor will have tight particle growth, mutual adhesion and serious agglomeration in the early growth stage, and it is difficult to improve the dispersibility in the later stage. If the oxygen-containing gas is started to be introduced too early, the precursor will be easily oxidized in the early nucleation stage, and MnO2 will be easily precipitated from the primary crystal form, causing uneven composition of the precursor.

[0014] Preferably, the oxygen-containing gas comprises air or oxygen, preferably air.

[0015] The oxygen-containing gas introduced in the present application is preferably air. If pure oxygen gas is used, the oxygen content of the system is too high, which will also affect the dispersion and specific surface area of the particles.

[0016] Preferably, the protective gas comprises nitrogen and / or inert gas.

[0017] Preferably, the flow rate of the oxygen-containing gas introduced is 5-15 L / h, for example, it can be 5 L / h, 7 L / h, 9 L / h, 11 L / h, 13 L / h or 15 L / h, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0018] The flow rate of the oxygen-containing gas introduced in the present application will affect the degree of oxidation of the system. If the flow rate of the oxygen-containing gas introduced is too small, the degree of oxidation introduced into the system is not enough, resulting in that the precursor particles are still severely agglomerated, and the dispersion improvement effect is not good. If the flow rate of the oxygen-containing gas introduced is too large, it will cause over-oxidation, resulting in the generation of a small amount of Mn3O4 and MnO2 and other impurities, which is not conducive to improving the dispersion of the particles, and the flow rate of the introduced gas is too large, which will additionally increase the production cost.

[0019] Preferably, the flow rate of the protective gas introduced is 50-200 L / h, for example, it can be 50 L / h, 75 L / h, 100 L / h, 125 L / h, 150 L / h, 175 L / h or 200 L / h, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0020] Similarly, the flow rate of the protective gas introduced in the present application will also affect the oxygen content in the system.

[0021] Preferably, the precipitant solution comprises sodium hydroxide solution and / or potassium hydroxide solution.

[0022] Preferably, the mass fraction of the precipitant solution is 30-35 wt%, for example, it can be 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt% or 35 wt%, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0023] Preferably, the complexing agent solution comprises oxalic acid and / or ammonia.

[0024] Preferably, the mass concentration of the complexing agent solution is 2-10 g / L, for example, it can be 2 g / L, 5 g / L, 8 g / L or 10 g / L, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0025] Preferably, the nickel-cobalt-manganese mixed salt solution, the precipitant solution and the complexing agent solution are passed into the base solution in parallel to carry out the co-precipitation reaction.

[0026] Preferably, the pH of the base solution is 11.5-12, for example, it can be 11.5, 11.75 or 12, and the base solution comprises water, the precipitant solution and the complexing agent solution.

[0027] Preferably, the nickel-cobalt-manganese mixed salt solution comprises any one or a combination of at least two of sulfate, nitrate or chloride.

[0028] Preferably, in the nickel-cobalt-manganese mixed salt solution, the molar ratio of nickel ions, cobalt ions and manganese ions is x:y:z, wherein x+y+z=1, z≥0.6, for example, it can be 0.6, 0.7, 0.8 or 0.9, 0

[0029] Preferably, the mass concentration of the nickel-cobalt-manganese mixed salt solution is 80-120 g / L, for example, it can be 80 g / L, 90 g / L, 100 g / L, 110 g / L or 120 g / L, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0030] Preferably, the temperature of the co-precipitation reaction is 50-60℃, for example, it can be 50℃, 55℃ or 60℃, the pH is 9.5-11.5, for example, it can be 9.5, 10, 11 or 11.5, and the stirring speed is 400-700 rpm, for example, it can be 400 rpm, 500 rpm, 600 rpm or 700 rpm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0031] Preferably, after the co-precipitation reaction, the filter pressing, washing and drying processes are further carried out.

[0032] Preferably, the temperature of the drying is 100-150℃, for example, it can be 100℃, 120℃, 140℃ or 150℃, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0033] Preferably, the washing comprises washing with lye and water for 2-5 times, for example, it can be 2 times, 3 times, 4 times or 5 times.

[0034] The water used in the washing is hot water.

[0035] As a preferred technical solution of the preparation method, the preparation method comprises the following steps:

[0036] The nickel-cobalt-manganese mixed salt solution, the precipitant solution and the complexing agent solution are passed into the bottom liquid in parallel under a protective gas atmosphere to perform a co-precipitation reaction, oxygen-containing gas is passed in after 2-10 hours of co-precipitation reaction, and then the co-precipitation reaction is continued, after the co-precipitation reaction is completed, filtration, washing and drying treatment at a temperature of 100-150 DEG C are performed to obtain the lithium-rich manganese-based precursor material;

[0037] The oxygen-containing gas includes air or oxygen, the flow rate of the oxygen-containing gas is 5-15 L / h, the protective gas includes nitrogen and / or inert gas, the flow rate of the protective gas is 50-200 L / h, the temperature of the co-precipitation reaction is 50-60 DEG C, the pH is 9.5-11.5, and the stirring speed is 400-700 rpm;

[0038] The pH of the bottom liquid is 11.5-12, the bottom liquid includes water, the precipitant solution and the complexing agent solution, the molar ratio of nickel ions, cobalt ions and manganese ions in the nickel-cobalt-manganese mixed salt solution is x:y:z, wherein x+y+z=1, z>=0.6, 0

[0039] In the second aspect, the present application provides a lithium-rich manganese-based precursor material as in the first aspect, which is prepared by the preparation method as in the first aspect.

[0040] In the third aspect, the present application provides a lithium-rich manganese-based positive electrode material, which is obtained by mixing and sintering the lithium-rich manganese-based precursor material as in the second aspect with a lithium source.

[0041] In the fourth aspect, the present application provides a battery, which includes the lithium-rich manganese-based positive electrode material as in the third aspect.

[0042] Compared with the prior art, the present application has the following beneficial effects:

[0043] (1) The present application introduces micro-oxidation in the precursor growth stage, only needs to add a tee joint at the gas inlet to introduce an oxygen-containing atmosphere, does not need to modify and increase the gas inlet pipeline of the existing kettle body, has a simple preparation process, and can reduce production cost.

[0044] (2) The present application performs micro-oxidation on the particles in the precursor growth stage, effectively avoids the defects of particle agglomeration and poor dispersibility of the current lithium-rich manganese precursor in the reaction stage, obtains a high-dispersibility lithium-rich manganese-based precursor with uniform particle distribution, and the specific surface area is maintained at about 25-30 m 2 / g, and the precursor with uniform particle distribution and high specific surface area is beneficial to the improvement of the structure stability and cycle performance of the subsequent positive electrode material. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 SEM image of the lithium-rich manganese-based precursor material obtained in Example 1 of the present application at a magnification of 3000 times;

[0046] Figure 2 SEM image of the lithium-rich manganese-based precursor material obtained in Example 1 of the present application at a magnification of 5000 times;

[0047] Figure 3 SEM image of the lithium-rich manganese-based precursor material obtained in Comparative Example 1 of the present application at a magnification of 3000 times;

[0048] Figure 4 SEM image of the lithium-rich manganese-based precursor material obtained in Comparative Example 1 of the present application at a magnification of 5000 times. DETAILED DESCRIPTION

[0049] 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 to help understand the present application and should not be regarded as specific limitations on the present application.

[0050] Example 1

[0051] The present embodiment provides a preparation method of a lithium-rich manganese-based precursor material, which comprises the following steps:

[0052] (1) 33.5 kg of pure water, 150 g of sodium hydroxide solution and 200 g of oxalic acid solution are added into a reaction kettle as a reaction bottom solution, and nitrogen is introduced for 3 h, with a nitrogen flow rate of 200 L / h, and the initial pH value of the bottom solution is controlled to be between 11.6 and 11.8;

[0053] (2) Under a nitrogen atmosphere, a nickel-cobalt-manganese mixed salt solution is introduced into the bottom solution of step (1) at a flow rate of 1.5 kg / h, a sodium hydroxide solution is introduced at a flow rate of 0.69 kg / h, and an oxalic acid solution is introduced at a flow rate of 0.18 kg / h, and a co-precipitation reaction is carried out. After 6 h of co-precipitation reaction, oxygen-containing gas is introduced, and then the co-precipitation reaction is continued. After the co-precipitation reaction is completed, the slurry after the reaction is transferred to a suction filter bottle, washed with alkali and hot water three times respectively, and then dried at a temperature of 120℃ to obtain the lithium-rich manganese-based precursor material;

[0054] The oxygen-containing gas is air, the flow rate of the oxygen-containing gas is 8 L / h, the flow rate of the nitrogen is 200 L / h, the temperature of the co-precipitation reaction is 58℃, the pH is controlled to be between 10.4 and 10.6, and the stirring speed is 600 rpm;

[0055] The mass concentration of the nickel-cobalt-manganese mixed salt solution is 100 g / L, the molar ratio of nickel ions, cobalt ions and manganese ions is 0.167:0.167:0.666, the mass fraction of the sodium hydroxide solution is 32%, and the concentration of oxalic acid is 5 g / L.

[0056] The SEM image of the lithium-rich manganese-based precursor material obtained in the example under 3000 times magnification is shown in FIG. 1, and the SEM image under 5000 times magnification is shown in FIG. 2. Figure 1 The SEM image of the lithium-rich manganese-based precursor material obtained in the example under 3000 times magnification is shown in FIG. 1, and the SEM image under 5000 times magnification is shown in FIG. 2. Figure 2 The SEM image of the lithium-rich manganese-based precursor material obtained in the example under 3000 times magnification is shown in FIG. 1, and the SEM image under 5000 times magnification is shown in FIG. 2.

[0057] Example 2

[0058] The example provides a preparation method of a lithium-rich manganese-based precursor material, and the preparation method comprises the following steps:

[0059] (1) 33.5 kg of pure water and 200 g of a sodium hydroxide solution and 250 g of an oxalic acid solution are added to a reaction kettle as a reaction bottom solution, and nitrogen is introduced to maintain for 3 h, the nitrogen flow rate is 200 L / h, and the initial pH value of the bottom solution is controlled to be 12;

[0060] (2) Under a nitrogen atmosphere, a nickel-cobalt-manganese mixed salt solution is introduced into the bottom solution of step (1) at a flow rate of 1.5 kg / h, a sodium hydroxide solution is introduced at a flow rate of 0.69 kg / h, and an oxalic acid solution is introduced at a flow rate of 0.18 kg / h, and a co-precipitation reaction is performed, after the co-precipitation reaction is performed for 2 h, an oxygen-containing gas is introduced, and then the co-precipitation reaction is continuously performed, after the co-precipitation reaction is completed, the slurry after the reaction is transferred to a suction filter bottle, and the slurry is washed three times with an alkali solution and hot water respectively, and then the slurry is dried at a temperature of 120 ℃ to obtain the lithium-rich manganese-based precursor material;

[0061] The oxygen-containing gas is air, the flow rate of the oxygen-containing gas is 15 L / h, the flow rate of the nitrogen is 200 L / h, the temperature of the co-precipitation reaction is 50 ℃, the pH value is controlled to be between 10.0 and 10.4, and the stirring speed is 400 rpm;

[0062] The mass concentration of the nickel-cobalt-manganese mixed salt solution is 80 g / L, the molar ratio of nickel ions, cobalt ions and manganese ions is 0.167:0.167:0.666, the mass fraction of the sodium hydroxide solution is 30%, and the concentration of oxalic acid is 2 g / L.

[0063] Example 3

[0064] The example provides a preparation method of a lithium-rich manganese-based precursor material, and the preparation method comprises the following steps:

[0065] (1) in the reaction kettle, add 33.5 kg of pure water, add 100 g of sodium hydroxide solution, 200 g of oxalic acid solution as the reaction bottom liquid, and pass nitrogen for 3 h, the nitrogen flow rate is 50 L / h, and the initial pH value of the bottom liquid is controlled to be 11.5;

[0066] (2) under the nitrogen atmosphere, the nickel-cobalt-manganese mixed salt solution is passed into the bottom liquid of step (1) at a flow rate of 1.5 kg / h, the sodium hydroxide solution is passed into the bottom liquid at a flow rate of 0.69 kg / h, and the oxalic acid solution is passed into the bottom liquid at a flow rate of 0.18 kg / h, and the coprecipitation reaction is carried out, after the coprecipitation reaction is carried out for 10 h, the oxygen-containing gas is started to be passed in, and then the coprecipitation reaction is continuously carried out, after the coprecipitation reaction is completed, the slurry after the reaction is completed is transferred to a filter bottle, and the slurry is washed three times with lye and hot water respectively, and then is dried at a temperature of 120 DEG C to obtain the lithium-rich manganese-based precursor material;

[0067] The oxygen-containing gas is air, the flow rate of the oxygen-containing gas is 5 L / h, the flow rate of the nitrogen is 50 L / h, the temperature of the coprecipitation reaction is 60 DEG C, the pH value is controlled to be between 10.6 and 11.0, and the stirring speed is 400 rpm;

[0068] The mass concentration of the nickel-cobalt-manganese mixed salt solution is 120 g / L, the molar ratio of nickel ions, cobalt ions and manganese ions is 0.30:0.05:0.65, the mass fraction of the sodium hydroxide solution is 35%, and the concentration of the oxalic acid is 10 g / L.

[0069] Example 4

[0070] The embodiment provides a preparation method of a lithium-rich manganese-based precursor material, and the preparation method comprises the following steps:

[0071] (1) in the reaction kettle, add 33.5 kg of pure water, add 100 g of sodium hydroxide solution, 200 g of oxalic acid solution as the reaction bottom liquid, and pass nitrogen for 3 h, the nitrogen flow rate is 50 L / h, and the initial pH value of the bottom liquid is controlled to be 11.5;

[0072] (2) under the nitrogen atmosphere, the nickel-cobalt-manganese mixed salt solution is passed into the bottom liquid of step (1) at a flow rate of 1.5 kg / h, the sodium hydroxide solution is passed into the bottom liquid at a flow rate of 0.69 kg / h, and the oxalic acid solution is passed into the bottom liquid at a flow rate of 0.18 kg / h, and the coprecipitation reaction is carried out, after the coprecipitation reaction is carried out for 10 h, the oxygen-containing gas is started to be passed in, and then the coprecipitation reaction is continuously carried out, after the coprecipitation reaction is completed, the slurry after the reaction is completed is transferred to a filter bottle, and the slurry is washed three times with lye and hot water respectively, and then is dried at a temperature of 120 DEG C to obtain the lithium-rich manganese-based precursor material;

[0073] The oxygen-containing gas is oxygen, the flow rate of the oxygen-containing gas is 6 L / h; the flow rate of the nitrogen gas is 120 L / h; the temperature of the co-precipitation reaction is 58℃, the pH is controlled between 10.4-10.6, and the stirring speed is 600 rpm.

[0074] The mass concentration of the nickel-cobalt-manganese mixed salt solution is 100 g / L, the molar ratio of nickel ions, cobalt ions and manganese ions is 0.30:0.05:0.65; the mass fraction of the sodium hydroxide solution is 32%, and the concentration of oxalic acid is 8 g / L.

[0075] Example 5

[0076] This example provides a preparation method of a lithium-rich manganese-based precursor material, which is the same as that of Example 1 except that the oxygen-containing gas is started to be introduced after the co-precipitation reaction of step (2) for 1 h.

[0077] Example 6

[0078] This example provides a preparation method of a lithium-rich manganese-based precursor material, which is the same as that of Example 1 except that the oxygen-containing gas is started to be introduced after the co-precipitation reaction of step (2) for 12 h.

[0079] Example 7

[0080] This example provides a preparation method of a lithium-rich manganese-based precursor material, which is the same as that of Example 1 except that the flow rate of the oxygen-containing gas is 3 L / h in step (2).

[0081] Example 8

[0082] This example provides a preparation method of a lithium-rich manganese-based precursor material, which is the same as that of Example 1 except that the flow rate of the oxygen-containing gas is 20 L / h in step (2).

[0083] Example 9

[0084] This example provides a preparation method of a lithium-rich manganese-based precursor material, which is the same as that of Example 1 except that the oxygen-containing gas is oxygen in step (2).

[0085] Comparative Example 1

[0086] This comparative example provides a preparation method of a lithium-rich manganese-based precursor material, which is the same as that of Example 1 except that no oxygen-containing gas is introduced in step (2), and the co-precipitation reaction is carried out in a nitrogen atmosphere all the time;

[0087] The SEM image of the lithium-rich manganese-based precursor material obtained by the present comparative example under 3000 times magnification is shown in Figure 3 The SEM image under 5000 times magnification is shown in Figure 4

[0088] Comparative Example 2

[0089] The present comparative example provides a preparation method of a lithium-rich manganese-based precursor material, which is the same as Example 1 except that nitrogen is not introduced in steps (1) and (2), but the co-precipitation reaction is always carried out in the oxygen-containing gas atmosphere.

[0090] The lithium-rich manganese-based precursor materials obtained by the above examples and comparative examples are subjected to particle size distribution and BET tests, and the test results are shown in Table 1:

[0091] Table 1

[0092]

[0093]

[0094] From Table 1, the following points can be seen:

[0095] (1) The (D90-D10) / D50 of the lithium-rich manganese precursor material obtained by the present application is below 0.71, and the BET is about 25-30 m 2 / g; in combination with Examples 1-4 and Comparative Example 1, it can be seen that the lithium-rich manganese-based precursor particles obtained by the present application have a uniform particle size distribution, achieving the purpose of improving the dispersity of the lithium-rich manganese-based precursor. The introduction of micro-oxidation effectively inhibits the collision and agglomeration of the precursor particles in the growth stage, and the BET of the precursor is significantly improved and maintained between 25-30 m 2 / g; the increase in BET is conducive to the full contact of the precursor with the lithium source in the subsequent positive electrode sintering process, and is crucial for the development of lithium-rich manganese-based positive electrode materials with stable structure and good cycle performance; as can be seen from Example 1 and Comparative Example 2, if the co-precipitation reaction is always carried out in the oxygen-containing gas without introducing nitrogen, the lithium-rich manganese precursor is directly oxidized to nickel-cobalt-manganese oxide, there are a large number of Mn3O4 and MnO2 impurities, and the particles are agglomerated and adhered to each other, the overall morphology and dispersity are poor, and the electrochemical performance of the subsequent positive electrode material is severely affected; as can be seen from Example 1 and Examples 5-9, the time when the oxygen-containing gas is introduced, the flow rate of the oxygen-containing gas, and the type of the oxygen-containing gas after the oxygen-containing gas is introduced will affect the oxidation degree of the system, thereby affecting the dispersity and specific surface area of the product.

[0096] (2) As can be seen from Figures 1-4 ​The SEM diagram of the precursor in Example 1 shows that the secondary particles of the precursor in Example 1 are uniformly distributed, and the dispersibility is obviously improved, and the sphericity of the overall morphology is also improved.

[0097] In conclusion, the present application provides a lithium-rich manganese-based precursor material, a preparation method and application thereof, the preparation method introduces an oxidation atmosphere in the growth stage of the precursor material, avoids the problems of close particle growth, easy agglomeration and poor morphology in the preparation process of the existing lithium-rich manganese precursor material, and obtains a lithium-rich manganese-based precursor material with high dispersibility and high specific surface.

[0098] The above description is merely 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 changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for preparing a lithium-rich manganese-based precursor material, characterized in that, The preparation method includes the following steps: Under a protective gas atmosphere, a nickel-cobalt-manganese mixed salt solution, a precipitant solution, and a complexing agent solution are mixed and a coprecipitation reaction is carried out. When the particles enter the growth stage, an oxygen-containing gas is introduced and the coprecipitation reaction is continued to obtain the lithium-rich manganese-based precursor material. After the coprecipitation reaction has continued for 2-10 hours, oxygen-containing gas is introduced. The flow rate of the oxygen-containing gas is 5-15 L / h; The oxygen-containing gas includes air or oxygen; The flow rate of the protective gas is 50-200 L / h; During the coprecipitation reaction stage, the protective gas is continuously introduced.

2. The preparation method according to claim 1, characterized in that, The oxygen-containing gas is air.

3. The preparation method according to claim 1, characterized in that, The protective gas includes nitrogen and / or an inert gas.

4. The preparation method according to claim 1, characterized in that, The precipitant solution includes sodium hydroxide solution and / or potassium hydroxide solution.

5. The preparation method according to claim 1, characterized in that, The mass fraction of the precipitant solution is 30-35 wt%.

6. The preparation method according to claim 1, characterized in that, The complexing agent solution includes oxalic acid and / or ammonia.

7. The preparation method according to claim 1, characterized in that, The mass concentration of the complexing agent solution is 2-10 g / L.

8. The preparation method according to claim 1, characterized in that, The nickel-cobalt-manganese mixed salt solution, precipitant solution, and complexing agent solution are introduced into the base liquid in parallel to carry out a co-precipitation reaction.

9. The preparation method according to claim 8, characterized in that, The pH of the base solution is 11.5-12, and the base solution includes water, a precipitant solution, and a complexing agent solution.

10. The preparation method according to claim 1, characterized in that, In the nickel-cobalt-manganese mixed salt solution, the molar ratio of nickel ions, cobalt ions, and manganese ions is x:y:z, where x+y+z=1, z≥0.6, 0<x<0.4, and 0<y<0.

4.

11. The preparation method according to claim 1, characterized in that, The coprecipitation reaction was carried out at a temperature of 50-60℃, a pH of 9.5-11.5, and a stirring speed of 400-700 rpm.

12. The preparation method according to claim 1, characterized in that, After the coprecipitation reaction was completed, filtration, washing and drying were performed.

13. The preparation method according to claim 12, characterized in that, The drying temperature is 100-150℃.

14. The preparation method according to claim 12, characterized in that, The washing process includes washing with alkaline solution and water 2-5 times in succession.

15. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: Under a protective gas atmosphere, a nickel-cobalt-manganese mixed salt solution, a precipitant solution, and a complexing agent solution are introduced concurrently into the bottom liquid to carry out a coprecipitation reaction. After the coprecipitation reaction lasts for 2-10 hours, oxygen-containing gas is introduced, and the coprecipitation reaction continues. After the coprecipitation reaction is completed, the material is subjected to filtration, washing, and drying at 100-150°C to obtain the lithium-rich manganese-based precursor material. The oxygen-containing gas includes air or oxygen, and the flow rate of the oxygen-containing gas is 5-15 L / h; the protective gas includes nitrogen and / or an inert gas, and the flow rate of the protective gas is 50-200 L / h; the temperature of the coprecipitation reaction is 50-60℃, the pH is 9.5-11.5, and the stirring speed is 400-700 rpm; during the coprecipitation reaction stage, the protective gas is continuously introduced; The pH of the base solution is 11.5-12, and it includes water, a precipitant solution and a complexing agent solution. In the nickel-cobalt-manganese mixed salt solution, the molar ratio of nickel ions, cobalt ions and manganese ions is x:y:z, where x+y+z=1, z≥0.6, 0<x<0.4, and 0<y<0.

4.

16. A lithium-rich manganese-based precursor material, characterized in that, The lithium-rich manganese-based precursor material is prepared using the preparation method described in any one of claims 1-15.

17. A lithium-rich manganese-based cathode material, characterized in that, The lithium-rich manganese-based cathode material is obtained by mixing and sintering the lithium-rich manganese-based precursor material as described in claim 16 with a lithium source.

18. A lithium-ion battery, characterized in that, The lithium-ion battery includes the lithium-rich manganese-based cathode material as described in claim 17.

Images