A high-nickel ternary precursor, a preparation method and application thereof

Abstract

The application discloses a high-nickel ternary precursor and a preparation method and application thereof, and belongs to the technical field of batteries. The high-nickel ternary precursor prepared by the preparation method has the characteristics of large specific surface area, large pressure particle size and low sulfur content. The battery prepared by using the high-nickel ternary precursor has high capacity and excellent cycle stability. Meanwhile, the preparation method is simple and efficient, and is beneficial to actual production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a high-nickel ternary precursor and a preparation method and application thereof. BACKGROUND

[0002] In recent years, countries around the world have reached a consensus on strengthening the sustainable development of the green economy. Under this consensus, major economies in the world have successively introduced relevant policies and actions to promote the transformation and development of the energy structure of their countries and have clearly striven to achieve the environmental protection goals set by the Paris Agreement. The implementation of the relevant policies and actions is guiding the reshaping of the global economic industrial structure, and new energy industries such as lithium are developing rapidly. Ternary materials are widely used in various fields due to their high energy density. However, with the gradual increase of the market, cobalt resources are becoming increasingly depleted. From the perspective of cost reduction and considering the future development trend of ternary materials, co-doping with other transition metal elements has become a hot research topic.

[0003] With the progress of material technology, all are pursuing high capacity, and increasing the nickel content is undoubtedly the most direct way, but the increase of nickel content will affect the cycle. Therefore, how to improve the capacity of the battery and the cycle performance of the battery has become the research focus of the positive electrode material; in the prior art, the high-nickel positive electrode material is often treated by modification, coating and other methods to improve the capacity and cycle performance, but the coating, modification and other methods increase the production process, which indirectly increases the cost, and it is difficult to reduce the sulfur content in the precursor material by coating, modification and other methods.

[0004] That is, the current cobalt-substituted ternary precursor product itself cannot meet the demand, and it is difficult to effectively solve the problem of replacing the expensive and toxic cobalt element while achieving good cycle performance, capacity, and low sulfur content in the product and good tap density; therefore, seeking a cobalt-substituted ternary precursor through various doping methods has become a problem to be solved.

[0005] SUMMARY

[0006] The purpose of the present application is to overcome the shortcomings of the prior art and provide a high-nickel ternary precursor with a large specific surface area, high pressure particle size and low sulfur content, which is applied to the preparation of batteries, and the cycle performance of the batteries prepared by the high-nickel ternary precursor is good, and the capacity is high.

[0007] To achieve the above-mentioned purpose, in the first aspect of the present application, the present application provides a high-nickel ternary precursor, the chemical general formula of the high-nickel ternary precursor is Ni x Mn y M z(OH)2, wherein 0.90≤x≤0.92, 0.02≤y≤0.06, 0.02≤z≤0.08, and x+y+z=1, and M is at least four elements selected from Mo, Na, Ti, Mg, W, Nb, and Zr.

[0008] The high-nickel ternary precursor provided by the application can realize a larger specific surface area, a higher pressure particle size, and a lower sulfur content of the high-nickel ternary precursor without adding cobalt elements, and when the high-nickel ternary precursor is used to prepare a battery, the battery has good cycle performance and a higher capacity.

[0009] In an embodiment, the M is at least four elements selected from Mo, Na, Ti, Mg, and Nb.

[0010] In an embodiment, the M is at least four elements selected from Mo, Ti, Mg, and Nb.

[0011] The selection of the M element affects the structure of the high-nickel ternary precursor, thereby affecting the pressure particle size and the specific surface area of the material, and further affecting the capacity and cycle performance of the battery prepared. When the M element is further selected to be the elements listed in the application, the comprehensive performance of the product is excellent.

[0012] In an embodiment, the primary particles of the high-nickel ternary precursor are honeycomb-shaped porous structures, and the secondary particles of the high-nickel ternary precursor are spherical porous structures.

[0013] The primary particles of the high-nickel ternary precursor prepared by the application are relatively thin honeycomb-shaped porous structures, or also called petal-shaped structures; the secondary particles are spherical porous particles obtained by continuing to grow on the outer surface of the primary particles, that is, the secondary particles are double-layer ring structures, in which the inner core is the primary particle, and the outer ring is a layered structure obtained by continuing to grow on the primary particle; wherein the porous structure of the secondary particle is in an internal communication state, which can make the product have stronger compression resistance in the first aspect, that is, the pressure particle size is higher, and can make the preparation process of washing and removing impurities more convenient in the second aspect, and can better remove the sulfur elements wrapped in the particles, further reduce the sulfur content in the product, and greatly shorten the diffusion path of lithium ions in the third aspect, thereby significantly improving the capacity performance of the battery.

[0014] In an embodiment, the D50 of the secondary particles of the high-nickel ternary precursor is 10.1-10.5 μm.

[0015] The high-nickel ternary precursor provided by the application has moderate D50 size of secondary particles, good stability, and can realize better compression resistance of the product in the D50 particle size range of the application.

[0016] In the second aspect of the application, the application provides a preparation method of the high-nickel ternary precursor, which comprises the following steps:

[0017] According to the stoichiometric ratio of Ni x Mn y M z The nickel salt, the manganese salt and the water-soluble compound containing the element M are mixed and dissolved in water according to the stoichiometric ratio of Ni

[0018] According to the stoichiometric ratio of Ni x Mn y M z The remaining water-insoluble compound containing the element M is dissolved in an alkali hydroxide aqueous solution according to the stoichiometric ratio of Ni

[0019] The mixed metal salt aqueous solution 1, the mixed metal salt aqueous solution 2 and ammonia water are flowed into a reaction bottom solution to perform a staged coprecipitation reaction, and after the reaction, centrifugation, drying, batch mixing and sieving are performed to obtain the high-nickel ternary precursor.

[0020] In the preparation method provided by the application, the compound containing the element M is divided into a water-soluble compound and a water-insoluble compound, and the two types of compounds are added into water and an alkali hydroxide aqueous solution, respectively, so that they can fully react in the subsequent staged coprecipitation reaction process and have a synergistic and partial inhibition effect on the morphology of the product, helping to form a high-nickel ternary precursor doped with specific elements; and the problem that the subsequent content has a large deviation caused by adding the water-insoluble compound into water can also be avoided.

[0021] In an embodiment, the staged coprecipitation reaction is divided into three stages, the first stage is nucleation and growth to D50≤3.5 μm, the second stage is particle growth to 3.5 μm

[0022] In an embodiment, the first stage has a pH value of 11.3

[0023] The present application divides the stage-by-stage co-precipitation reaction into three stages according to the D50 of the particles, and controls the pH value, rotation speed and temperature of each different stage for nucleation or particle growth, so as to ensure that the primary particles of the high-nickel ternary precursor obtained are honeycomb porous structure, the secondary particles are spherical porous structure, and the pores of the spherical porous structure are internally connected; and further, the product can achieve excellent pressure particle size, extremely low sulfur content and relatively high specific surface area.

[0024] In an embodiment, in the stage-by-stage co-precipitation, when the D50 of the particles is ≥10 μm, seed crystals with D50 of 3 μm≤D50≤5 μm are added.

[0025] The introduction of the seed crystals can further control the D50 of the generated high-nickel ternary precursor within the target value range of 10.1-10.5 μm of the present application, and further ensure the pressure particle size and stability of the product.

[0026] In an embodiment, the seed crystals are particles with D50 of 3 μm≤D50≤5 μm prepared by the preparation method of the high-nickel ternary precursor.

[0027] The preparation method of the seed crystals is the same as that of the high-nickel multi-element precursor, except that particles within a specific D50 range are selected; in this way, the destructive effect of the introduction of other substances on the structure can be avoided.

[0028] In an embodiment, in the mixed metal salt aqueous solution 1, the total concentration of metal ions is 1.6-2.2 mol / L.

[0029] And / or, in the mixed metal salt aqueous solution 2, the total concentration of metal ions is 0.03-0.1 mol / L, and the concentration of alkali metal hydroxide is 6-12 mol / L.

[0030] Illustratively, the total concentration of metal ions in the mixed metal salt aqueous solution 1 can be 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2.0 mol / L, 2.1 mol / L, 2.2 mol / L, etc., or can be any point value or range value between any two points within 1.6-2.2 mol / L.

[0031] Exemplarily, the total concentration of metal ions in the mixed metal salt aqueous solution 2 can be 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, 0.10 mol / L, or the like, or can be any point value or range value between 0.03-0.1 mol / L; the concentration of alkali metal hydroxide can be 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, 10 mol / L, 11 mol / L, 12 mol / L, or the like, or can be any point value or range value between 6-12 mol / L.

[0032] In an embodiment, the ammonia water concentration in the reaction base solution is 2-5 g / L, and the pH value of the reaction base solution is 11.3-12.0.

[0033] And / or, the ammonia water concentration is 1.8-3.2 g / L.

[0034] Exemplarily, the ammonia water concentration in the reaction base solution can be 2.0 g / L, 2.5 g / L, 3.0 g / L, 3.5 g / L, 4.0 g / L, 4.5 g / L, 5.0 g / L, or the like, or can be any point value or range value between 2-5 g / L.

[0035] The metal ions with a suitable molar concentration and the alkali metal hydroxide and the reaction base solution can moderate the ion concentration in the reaction system, which is conducive to the formation of particles and avoids the problem of structural formation failure caused by excessive aggregation of particles.

[0036] In an embodiment, the alkali metal hydroxide is selected from at least one of sodium hydroxide and potassium hydroxide.

[0037] In an embodiment, the flow rate ratio of the mixed metal salt aqueous solution 1, the mixed metal salt aqueous solution 2 and the ammonia water flowing into the reaction base solution is mixed metal salt aqueous solution 1:mixed metal salt aqueous solution 2:ammonia water=(15-20):(5-7):(1-2).

[0038] During the process of particle nucleation and growth, the mixed metal salt aqueous solution 1, the mixed metal salt aqueous solution 2 and the ammonia water are continuously introduced, and in different co-precipitation stages, the pH value of a specific stage is realized by adjusting the flow rate of the mixed metal salt aqueous solution 1, the mixed metal salt aqueous solution 2 and the ammonia water.

[0039] In an embodiment, the nickel salt is selected from at least one of nickel sulfate hexahydrate and nickel chloride;

[0040] And / or, the manganese salt is selected from manganese sulfate monohydrate.

[0041] In an embodiment, the water-soluble compound containing M elements is selected from at least one of sodium metaaluminate, titanyl sulfate, magnesium sulfate, magnesium chloride, niobium oxalate, and zirconium sulfate.

[0042] And / or, the non-water-soluble compound containing M elements is selected from at least one of molybdenum trioxide, titanium sulfate, tungsten trioxide, and zirconium oxide.

[0043] In a third aspect of the present application, the present application provides a high-nickel ternary positive electrode material, which is prepared from the high-nickel ternary precursor or the high-nickel ternary precursor prepared by the preparation method described in the present application.

[0044] In a fourth aspect of the present application, the present application provides a battery comprising the high-nickel ternary positive electrode material described in the present application.

[0045] Compared with the prior art, the present application has the following beneficial effects:

[0046] The high-nickel ternary precursor provided in the present application, by selecting appropriate ratios of Ni, Mn, and M elements and specific M elements, and by dividing different stages according to the D50 value of the particles in the coprecipitation and controlling the pH value, rotation speed, and temperature in different stages, i.e., stage-by-stage coprecipitation, a high-nickel ternary precursor with honeycomb-like porous structure of primary particles and spherical porous structure of secondary particles and interconnected porous interiors is prepared. Under the technical solution provided in the present application, a larger specific surface area, higher pressure particle size, and lower sulfur content of the high-nickel ternary precursor can be achieved without adding expensive and toxic cobalt elements. Specifically, the specific surface area BET of the obtained high-nickel ternary precursor is above 15.82 m 2 / g, the pressure particle size is above 0.280 μm, and the sulfur content is below 2300 ppm. When the high-nickel ternary precursor prepared in the present application is used to prepare a battery, the obtained battery has good cycle performance and high capacity. Specifically, the charge capacity of the obtained battery at 0.1C is above 221.0 mAh / g, and the capacity retention rate at 0.1C at room temperature is above 81.8%. At the same time, the preparation method provided in the present application is simple and efficient, which is conducive to actual production. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 SEM image of the high-nickel ternary precursor prepared in Example 1;

[0048] Figure 2 Schematic diagram of the honeycomb-like porous structure of the high-nickel ternary precursor prepared in Example 1;

[0049] Figure 3A slice diagram of the high-nickel ternary precursor prepared in Example 1;

[0050] Figure 4 An SEM diagram of the high-nickel ternary precursor prepared in Example 11;

[0051] Figure 5 A slice diagram of the high-nickel ternary precursor prepared in Example 11. DETAILED DESCRIPTION

[0052] For the purpose of better illustrating the purpose, technical scheme and advantages of the present application, the present application will be further described in conjunction with specific embodiments.

[0053] Unless otherwise specified, the raw materials used in the present application are conventional commercially available raw materials, and the raw materials used in the parallel examples or comparative examples in the present application are consistent.

[0054] Example 1

[0055] The present application provides a high-nickel ternary precursor, the chemical general formula of the high-nickel ternary precursor is Ni 0.90 Mn 0.03 M 0.07 (OH)2, wherein M is Ti, Mg, Nb and Mo, and the molar ratio of Ti, Mg, Nb and Mo in M is Ti:Mg:Nb:Mo = 2:2:2:1.

[0056] The preparation method of the high-nickel ternary precursor comprises the following steps:

[0057] (1) According to the stoichiometric ratio of Ni 0.90 Mn 0.03 M 0.07 (OH)2, nickel sulfate hexahydrate, manganese sulfate monohydrate, titanyl sulfate, anhydrous magnesium sulfate and niobium oxalate are mixed and dissolved in water to obtain a mixed metal salt aqueous solution 1 with a total metal ion concentration of 1.8 mol / L;

[0058] (2) According to the stoichiometric ratio of Ni 0.90 Mn 0.03 M 0.07 (OH)2, molybdenum trioxide is dissolved in sodium hydroxide aqueous solution to obtain a mixed metal salt aqueous solution 2; wherein the concentration of metal ions in the mixed metal salt aqueous solution 2 is 0.07 mol / L, and the concentration of sodium hydroxide is 9 mol / L;

[0059] (3) The reaction kettle bottom liquid is ensured to submerge the pH probe, the reaction kettle is heated to 72℃, the stirring is started and the stirring speed is maintained at 500 rpm, ammonia water is added to adjust the ammonia water concentration of the system to 2.5 g / L, then sodium hydroxide is used to adjust the pH value of the system to 12 to obtain a reaction bottom liquid;

[0060] (4) mixed metal salt aqueous solution 1, mixed metal salt aqueous solution 2 and ammonia water with a concentration of 2.5 g / L are flowed into the reaction bottom solution at a flow rate of 15:5:1 to carry out a staged coprecipitation reaction; the coprecipitation reaction is divided into three stages, and the temperature is controlled at 60℃; the first stage is nucleation and growth to D50≤3.5 μm, the first stage pH value is 11.7±0.1, the stirring speed r is 500 rpm, the second stage is particle growth to 3.5 μm<D50≤7.5 μm, the second stage pH value is 11.0±0.1, the stirring speed r is 350 rpm, and the third stage is particle growth to the target value 10.1 μm≤D50≤10.5 μm, the third stage pH value is 10.7±0.1, and the stirring speed r is 280 rpm; wherein when D50 is 10 μm, seed particles with D50 of 4 μm are added, and the seed particles are prepared by the preparation method of the high-nickel ternary precursor with D50 of 4 μm;

[0061] (5) After the staged coprecipitation reaction is completed, centrifugation is carried out at a speed of 100 rpm, the precipitate is collected and dried at 120℃ for 12h, the dried product is mixed together and passed through a 300 mesh screen, and the undersize material is collected to obtain the high-nickel ternary precursor.

[0062] Example 2

[0063] The embodiment of the present application provides a high-nickel ternary precursor, which is different from the embodiment 1 in that the difference lies in the difference in the preparation method, and the preparation method of the high-nickel ternary precursor of the embodiment comprises the following steps:

[0064] (1) according to the stoichiometric ratio of Ni 0.90 Mn 0.03 M 0.07 (OH)2, nickel chloride, manganese sulfate monohydrate, titanyl sulfate, magnesium chloride and niobium oxalate are mixed and dissolved in water to obtain a mixed metal salt aqueous solution 1 with a total metal ion concentration of 1.6 mol / L;

[0065] (2) according to the stoichiometric ratio of Ni 0.90 Mn 0.03 M 0.07 (OH)2, molybdenum trioxide is dissolved in sodium hydroxide aqueous solution to obtain a mixed metal salt aqueous solution 2; wherein the concentration of metal ions in the mixed metal salt aqueous solution 2 is 0.03 mol / L, and the concentration of sodium hydroxide is 6 mol / L;

[0066] (3) the reaction kettle bottom liquid is ensured to submerge the pH probe, the reaction kettle is heated to 72℃, the stirring speed is maintained at 500 rpm, ammonia water is added to adjust the ammonia water concentration of the system to 3.5 g / L, then sodium hydroxide is used to adjust the pH value of the system to 11.5, and the reaction bottom solution is obtained;

[0067] (4) mixed metal salt aqueous solution 1, mixed metal salt aqueous solution 2 and ammonia water with a concentration of 2.5 g / L are flowed into the reaction bottom solution at a flow rate of 15:5:1 to carry out a staged coprecipitation reaction; the coprecipitation reaction is divided into three stages, and the temperature is controlled to be 50℃; the first stage is nucleation and growth to D50≤3.5 μm, the first stage pH value is 11.5±0.1, the stirring speed r is 480 rpm, the second stage is particle growth to 3.5 μm<D50≤7.5 μm, the second stage pH value is 11.2±0.1, the stirring speed r is 400 rpm, and the third stage is particle growth to the target value 10.1 μm≤D50≤10.5 μm, the third stage pH value is 10.7±0.1, and the stirring speed r is 300 rpm; wherein when D50 is 10 μm, seed particles with D50 of 3 μm are added, and the seed particles are prepared by the preparation method of the high-nickel ternary precursor.

[0068] (5) After the staged coprecipitation reaction is completed, centrifugation is carried out at a speed of 100 rpm, the precipitate is collected and dried at 120℃ for 12h, the dried product is mixed together and passed through a 300 mesh screen, and the undersize material is collected to obtain the high-nickel ternary precursor.

[0069] Example 3

[0070] The embodiment of the present application provides a high-nickel ternary precursor, which is different from the embodiment 1 in that the difference lies in the difference in the preparation method, and the preparation method of the high-nickel ternary precursor of the embodiment comprises the following steps:

[0071] (1) according to the stoichiometric ratio of Ni 0.90 Mn 0.03 M 0.07 (OH)2, nickel sulfate hexahydrate, manganese sulfate monohydrate, titanyl sulfate, anhydrous magnesium sulfate and niobium oxalate are mixed and dissolved in water to obtain a mixed metal salt aqueous solution 1 with a total metal ion concentration of 2.2 mol / L;

[0072] (2) according to the stoichiometric ratio of Ni 0.90 Mn 0.03 M 0.07 (OH)2, molybdenum trioxide is dissolved in sodium hydroxide aqueous solution to obtain a mixed metal salt aqueous solution 2; wherein the concentration of metal ions in the mixed metal salt aqueous solution 2 is 0.1 mol / L, and the concentration of sodium hydroxide is 12 mol / L;

[0073] (3) the reaction kettle bottom liquid is ensured to submerge the pH probe, the reaction kettle is heated to 72℃, the stirring speed is maintained at 500 rpm, ammonia water is added to adjust the ammonia water concentration of the system to 5 g / L, then sodium hydroxide is used to adjust the pH value of the system to 11.3 to obtain a reaction bottom solution;

[0074] (4) the mixed metal salt aqueous solution 1, the mixed metal salt aqueous solution 2 and the ammonia water with a concentration of 2.5 g / L are flowed into the reaction bottom solution at a flow rate of 20:7:2 to perform a staged coprecipitation reaction; the coprecipitation reaction is divided into three stages, and the temperature is controlled to be 75℃; the first stage is nucleation and growth to D50≤3.5 μm, the first stage pH value is 11.9±0.1, the stirring speed r is 550 rpm, the second stage is particle growth to 3.5 μm<D50≤7.5 μm, the second stage pH value is 11.0±0.1, the stirring speed r is 450 rpm, and the third stage is particle growth to the target value 10.1 μm≤D50≤10.5 μm, the third stage pH value is 10.7±0.1, and the stirring speed r is 260 rpm; wherein when D50 is 10 μm, seed particles with D50 of 5 μm are added, and the seed particles are prepared by the preparation method of the high-nickel ternary precursor.

[0075] (5) after the staged coprecipitation reaction is completed, centrifugation is performed at a speed of 100 rpm, the precipitate is collected and dried at 120℃ for 12 h, the dried product is mixed together and passed through a 300 mesh screen, the undersize is collected, and the high-nickel ternary precursor is obtained.

[0076] Example 4

[0077] The embodiment of the present application provides a high-nickel ternary precursor, which is different from the high-nickel ternary precursor of example 1 in that no seed particles are added in step (4).

[0078] Example 5

[0079] The embodiment of the present application provides a high-nickel ternary precursor, which is different from the high-nickel ternary precursor of example 1 in that in step (4), the first stage is nucleation and growth to D50≤5 μm, and the second stage is particle growth to 5 μm<D50≤9.0 μm.

[0080] Example 6

[0081] The embodiment of the present application provides a high-nickel ternary precursor, which is different from the high-nickel ternary precursor of example 1 in that in step (4), the first stage pH value is 11.0±0.1, and the second stage pH value is 10.5±0.1.

[0082] Example 7

[0083] The embodiment of the present application provides a high-nickel ternary precursor, which is different from the high-nickel ternary precursor of example 1 in that in step (4), the first stage stirring speed r is 400 rpm, and the second stage stirring speed r is 250 rpm.

[0084] Example 8

[0085] The embodiment of the present application provides a high-nickel ternary precursor, which is different from the high-nickel ternary precursor of the embodiment 1 in that the chemical general formula of the high-nickel ternary precursor provided by the embodiment is Ni 0.92 Mn 0.06 M 0.02 (OH)2, wherein M is Ti, Mg, Nb and Mo.

[0086] Embodiment 9

[0087] The embodiment of the present application provides a high-nickel ternary precursor, which is different from the high-nickel ternary precursor of the embodiment 1 in that the chemical general formula of the high-nickel ternary precursor provided by the embodiment is Ni 0.90 Mn 0.03 M 0.07 (OH)2, wherein M is Ti, Mg, Nb, Mo and Na, and the molar ratio of Ti, Mg, Nb and W in the M is Ti:Mg:Nb:Mo:Na=1:2:2:1:1.

[0088] In the preparation method of the high-nickel ternary precursor, the compound containing Na is sodium metaaluminate, which is mixed with nickel salt, manganese salt and the like to form a mixed metal salt aqueous solution 1.

[0089] Embodiment 10

[0090] The embodiment of the present application provides a high-nickel ternary precursor, which is different from the high-nickel ternary precursor of the embodiment 1 in that the chemical general formula of the high-nickel ternary precursor provided by the embodiment is Ni 0.90 Mn 0.03 M 0.07 (OH)2, wherein M is Ti, Mg, Nb and W, and the molar ratio of Ti, Mg, Nb and W in the M is Ti:Mg:Nb:W=2:2:2:1.

[0091] In the preparation method of the high-nickel ternary precursor, the compound containing W is tungsten trioxide, which is mixed with a sodium hydroxide aqueous solution to form a mixed metal salt aqueous solution 2.

[0092] Embodiment 11

[0093] The embodiment of the present application provides a high-nickel ternary precursor, which is different from the high-nickel ternary precursor of the embodiment 1 in that the chemical general formula of the high-nickel ternary precursor provided by the embodiment is Ni 0.90 Mn 0.03 M 0.07 (OH)2, wherein M is Ti, Mg, Nb and W, and the molar ratio of Ti, Mg, Nb and W in the M is Ti:Mg:Zr:Mo=2:2:2:1.

[0094] The compound containing Zr in the preparation method of the high-nickel ternary precursor of the embodiment is zirconium sulfate, which is mixed with nickel salt, manganese salt, etc. to form a mixed metal salt aqueous solution 1.

[0095] Comparative Example 1

[0096] The comparative example of the present application provides a high-nickel ternary precursor, which is different from the high-nickel ternary precursor of Embodiment 1 in that the chemical general formula of the high-nickel ternary precursor provided in the embodiment is Ni 0.85 Mn 0.08 M 0.07 (OH)2.

[0097] Comparative Example 2

[0098] The comparative example of the present application provides a high-nickel ternary precursor, which is different from the high-nickel ternary precursor of Embodiment 1 in that the chemical general formula of the high-nickel ternary precursor provided in the embodiment is Ni 0.95 Mn 0.03 M 0.02 (OH)2.

[0099] Comparative Example 3

[0100] The comparative example of the present application provides a high-nickel ternary precursor, which is different from the high-nickel ternary precursor of Embodiment 1 in that the chemical general formula of the high-nickel ternary precursor provided in the embodiment is Ni 0.90 Mn 0.03 M 0.07 (OH)2, wherein M is Ti, Nb and Mo, and the molar ratio of Ti, Nb and Mo in M is Ti:Nb:Mo = 2:2:1.

[0101] Comparative Example 4

[0102] The comparative example of the present application provides a high-nickel ternary precursor, which is different from the high-nickel ternary precursor of Embodiment 1 in that the chemical general formula of the high-nickel ternary precursor provided in the embodiment is Ni 0.90 Mn 0.03 M 0.07 (OH)2, wherein M is Ti and Mg, and the molar ratio of Ti and Mg in M is Ti:Mg = 1:1.

[0103] Comparative Example 5

[0104] The comparative example of the present application provides a high-nickel ternary precursor, which is different from the high-nickel ternary precursor of Embodiment 1 in that the chemical general formula of the high-nickel ternary precursor provided in the embodiment is Ni 0.90 Mn 0.03 M 0.07 (OH)2, wherein M is Ti, Al, Nb and Mo.

[0105] In the preparation method of the high-nickel ternary precursor of the present application, the compound containing Al is aluminum sulfate, which is mixed with nickel salt, manganese salt, etc. to form a mixed metal salt aqueous solution 1.

[0106] Comparative Example 6

[0107] The present application provides a high-nickel ternary precursor, which has a chemical formula of Ni 0.90 Mn 0.03 Co 0.07 (OH)2.

[0108] The preparation method of the high-nickel ternary precursor comprises the following steps:

[0109] (1) According to the stoichiometric ratio of Ni 0.90 Mn 0.03 Co 0.07 (OH)2, nickel sulfate hexahydrate, manganese sulfate monohydrate and cobalt sulfate are mixed and dissolved in water to obtain a mixed metal salt aqueous solution with a total metal ion concentration of 1.8 mol / L;

[0110] (2) A sodium hydroxide alkali solution with a concentration of 9 mol / L is prepared;

[0111] (3) The bottom liquid of the reaction kettle is ensured to submerge the pH probe, the reaction kettle is heated to 72°C, the stirring speed is maintained at 500 rpm, ammonia water is added to adjust the ammonia water concentration of the system to 2.5 g / L, then sodium hydroxide is used to adjust the pH value of the system to 12, and the reaction bottom liquid is obtained;

[0112] (4) The mixed metal salt aqueous solution, the sodium hydroxide alkali solution and ammonia water with a concentration of 2.5 g / L are flowed into the reaction bottom liquid at a flow rate of 1:3:10 to perform a staged coprecipitation reaction; the coprecipitation reaction is divided into three stages, and the temperature is controlled at 60°C; the first stage is nucleation and growth to D50≤3.5 μm, the first stage pH value is 11.7±0.1, the stirring speed r is 500 rpm, the second stage is particle growth to 3.5 μm

[0113] (5) After the staged coprecipitation reaction is completed, centrifugation is performed at a speed of 100 rpm, the precipitate is collected and dried at 120°C for 12 h, the dried product is mixed together and passed through a 300 mesh sieve, and the undersize material is collected to obtain the high-nickel ternary precursor.

[0114] Effect Example

[0115] The performance of the high-nickel ternary precursors prepared in Examples 1-11 and Comparative Examples 1-6 is verified in the effect example, specifically including the following aspects:

[0116] 1. Particle size information: the D50 particle size and particle size distribution coefficient P value of the prepared high-nickel ternary precursor are recorded by a particle size instrument, wherein the calculation method of P value is: P = (D90-D10) / D50;

[0117] 2. Specific surface area (BET): the specific surface area of the prepared high-nickel ternary precursor is tested by the method of nitrogen adsorption, and the specific testing process is to test the specific surface area by using nitrogen adsorption;

[0118] 3. Sulfur content: the sulfur content in the prepared high-nickel ternary precursor is tested by ICP titration

[0119] 4. Pressure particle size: the pressure resistance of the high-nickel ternary precursor with D50 particle size under 0.75T is tested by using a tap density instrument;

[0120] Further, the prepared high-nickel ternary precursor is prepared into a battery, and the specific preparation process is to prepare a button cell in an argon glove box, and the cathode is a lithium sheet; the performance of the prepared battery is tested, including the following aspects:

[0121] 5. Charge capacity: the prepared battery is tested for charge capacity according to the blue light system at 2.8-4.3V;

[0122] 6. Cycle capacity: the prepared battery is tested for cycle capacity at 0.1C and room temperature (25°C), and the capacity retention rate after 100 cycles is recorded;

[0123] In addition, the high-nickel ternary precursor prepared in Example 1 is observed, and the SEM diagram thereof is shown in Figure 1 , and the structural schematic diagram is shown in Figure 2 , it can be seen from Figure 1 that the surface of the prepared high-nickel ternary precursor presents a porous structure; the slice diagram is shown in Figure 3 , and it can be seen from Figure 3 that it is a clear double-layer ring structure, wherein the inner core is a primary particle, and the outer ring is a particle obtained by subsequent further growth;

[0124] Further observation of the high-nickel ternary precursor prepared in Example 11 is observed, and the SEM diagram thereof is shown in Figure 4 , and the structural schematic diagram is shown in Figure 4It can be seen from the figure that the morphology of the prepared high-nickel ternary precursor is obviously changed, and the surface is not a porous structure, but a hexagonal sheet insertion shape; the slice figure is shown in Figure 5 It can be seen from the figure that the double-layer ring structure in the high-nickel ternary precursor obtained in Example 1 is changed to a porous structure. Figure 5

[0125] The results obtained by the above 1-6 tests are shown in Table 1.

[0126] Table 1

[0127]

[0128]

[0129] It can be seen from Table 1 that when the technical solution of the present application is adopted, the D50 particle size of the obtained high-nickel ternary precursor is appropriate, between 10.10-10.50 μm, and the particle size distribution coefficient is smaller, below 1.35, that is, the particle size distribution of the prepared high-nickel ternary precursor is uniform; at the same time, the specific surface area of the obtained high-nickel ternary precursor is above 15.82 m 2 / g, the sulfur content is above 2300 ppm, and the pressure particle size is above 0.280 μm, when the corresponding battery is prepared, the obtained battery has excellent capacity and cycle capacity, specifically, the 0.1C capacity is above 221.0 mAh / g, and the cycle retention rate is above 81.8%; that is, the capacity and cycle performance of the obtained battery are more excellent than those of Comparative Example 6 (a battery prepared from a conventional cobalt-containing high-nickel ternary precursor); compared with Comparative Example 6, the capacity of the battery prepared by adopting the technical solution of the present application is increased by 2.41-4.54%, and the cycle retention rate is increased by 4.87-11.54%, and the performance of the high-nickel ternary precursor obtained by the present application is also more excellent than that of Comparative Example 6; compared with Comparative Example 6, the specific surface area of the high-nickel ternary precursor prepared by adopting the technical solution of the present application is increased by 74.81-364.09%, the sulfur content is reduced by 21.66-75.03%, and the pressure particle size is increased by 7.69-46.54%;

[0130] It can be seen from Examples 1-3 and Examples 4-7 that the preparation method of the high-nickel ternary precursor provided by the present application also affects the performance of the product; when the steps and parameters of the preparation method are further optimized within the range given by the present application, the specific surface area of the obtained high-nickel ternary precursor is larger, the sulfur content is lower, and the pressure particle size is larger, specifically, the specific surface area is above 41.50 m 2 ​above, the sulfur content is below 750 ppm, and the pressure particle size is above 0.375 pm; the battery prepared has more excellent capacity and cycle performance, the capacity is above 225.3 mAh / g, and the cycle retention rate is above 86.8%;

[0131] As can be seen from Example 1, Example 8 and Comparative Examples 1-2, when the introduced M element is unchanged, but the molar ratio of Ni, Mn and M element is changed, the performance of the product is also obviously affected, when the molar ratio of Ni, Mn and M element is not within the range given in the application, the comprehensive performance of the obtained product is obviously decreased, compared with Example 1, the specific surface area of the high-nickel ternary material obtained in Comparative Example 1-2 is decreased by 78.00-82.21%, the sulfur content is increased by 2.9-3.2 times, and the pressure particle size is reduced by 52.63-57.89%; the capacity of the battery obtained in Comparative Example 1-2 is decreased by 4.66-5.54%, and the cycle retention rate is decreased by 13.79-14.60%;

[0132] As can be seen from Example 1, Example 9-11 and Comparative Examples 3-5, the number and type of M elements introduced in the high-nickel ternary precursor will affect the comprehensive performance of the product, when the type of M element selected in Comparative Examples 3-4 is within the range of the application, but the number of types is not within the range of the application, compared with Example 1, the specific surface area of the high-nickel ternary material obtained in Comparative Examples 3-4 is decreased by 73.25-80.10%, the sulfur content is increased by 2.6-2.8 times, and the pressure particle size is reduced by 44.74-50.00%; the capacity of the battery obtained in Comparative Examples 3-4 is decreased by 3.33-6.87%, and the cycle retention rate is decreased by 13.10-15.17%; when the type of M element selected in Comparative Example 5 is not within the range of the application, compared with Example 1, the specific surface area of the obtained high-nickel ternary material is decreased by 78.19%, the sulfur content is increased by 3.0 times, and the pressure particle size is reduced by 34.21%; the capacity of the battery obtained in Comparative Example 5 is decreased by 3.99%, and the cycle retention rate is decreased by 15.86%.

Claims

1. A method for preparing a high-nickel ternary precursor, characterized in that, The high-nickel ternary precursor has a chemical formula of Ni x Mn y M z (OH)2, wherein 0.90≤x≤0.92, 0.02≤y≤0.06, 0.02≤z≤0.08, and x+y+z=1, and M is at least 4 selected from Mo, Na, Ti, Mg, W, Nb, and Zr. The preparation method comprises the following steps: According to Ni x Mn y M z The stoichiometric ratio of (OH)2is mixed and dissolved in water to obtain a mixed metal salt aqueous solution 1. According to Ni x Mn y M z The non-aqueous compound containing M element is dissolved in the aqueous alkali hydroxide solution in a stoichiometric ratio of M(OH)2, to obtain a mixed metal salt aqueous solution 2. The mixed metal salt aqueous solution 1, the mixed metal salt aqueous solution 2 and the ammonia water flow into the reaction bottom solution for a staged coprecipitation reaction, and after the reaction, centrifugation, drying, batch mixing and sieving are performed to obtain the high-nickel ternary precursor. In the staged coprecipitation, when the D50 of the particles is greater than or equal to 10 μm, seed crystals with a D50 of 3 μm≤D50≤5 μm are added.

2. The production method according to claim 1, characterized by, The primary particles of the high-nickel ternary precursor have a honeycomb-like porous structure, and the secondary particles of the high-nickel ternary precursor have a spherical porous structure.

3. The preparation method according to claim 2, characterized in that, The D50 of the secondary particles of the high-nickel ternary precursor is 10.1-10.5 μm.

4. The method of claim 1, wherein, The staged coprecipitation reaction is divided into three stages, the first stage is nucleation and growth to a D50≤3.5 μm, the second stage is particle growth to 3.5 μm<D50≤7.5 μm, and the third stage is particle growth to a target value of 10.1 μm≤D50≤10.5 μm.

5. The preparation method according to claim 4, characterized in that, In the first stage, the pH value is 11.3<pH value≤12, the stirring speed r is 450 rpm<r≤550 rpm, and the temperature is 50-75 ℃; in the second stage, the pH value is 10.8<pH value≤11.3, the stirring speed r is 300 rpm<r≤450 rpm, and the temperature is 50-75 ℃; in the third stage, the pH value is 10.5<pH value≤10.8, the stirring speed r is 250 rpm<r≤300 rpm, and the temperature is 50-75 ℃.

6. The preparation method according to claim 1, characterized in that, The seed crystals are particles with a D50 of 3 μm≤D50≤5 μm prepared by the preparation method of the high-nickel ternary precursor.

7. The preparation method according to claim 1, characterized in that, In the mixed metal salt aqueous solution 1, the total concentration of metal ions is 1.6-2.2 mol / L; and / or, in the mixed metal salt aqueous solution 2, the total concentration of metal ions is 0.03-0.1 mol / L, and the concentration of alkali metal hydroxide is 6-12 mol / L.

8. The preparation method according to claim 1, characterized in that, In the reaction bottom solution, the concentration of ammonia water is 2-5 g / L, and the pH value of the reaction bottom solution is 11.3-12.0; and / or, the concentration of ammonia water is 1.8-3.2 g / L.

9. The method of claim 1, wherein, When the mixed metal salt aqueous solution 1, the mixed metal salt aqueous solution 2 and the ammonia water flow into the reaction bottom solution, the flow rate ratio is mixed metal salt aqueous solution 1:mixed metal salt aqueous solution 2:ammonia water=(15-20):(5-7):(1-2).

10. The method of claim 1, wherein, The nickel salt is selected from at least one of nickel sulfate hexahydrate and nickel chloride; The manganese salt is selected from manganese sulfate monohydrate.

11. The method of claim 1, wherein, The water-soluble compound containing element M is selected from at least one of sodium metaaluminate, titanyl sulfate, magnesium sulfate, magnesium chloride, niobium oxalate and zirconium sulfate; and / or, the non-water-soluble compound containing element M is selected from at least one of molybdenum trioxide, titanium sulfate, tungsten trioxide and zirconium oxide.

12. A high nickel ternary precursor, characterized in that, The high-nickel ternary precursor is prepared by the preparation method of any one of claims 1-11.

13. A high nickel ternary cathode material, characterized in that, The high-nickel ternary positive electrode material is prepared from the high-nickel ternary precursor of claim 12.

14. A battery, characterized by The battery comprises the high-nickel ternary positive electrode material of claim 13.

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