High-nickel ternary precursor, preparation method thereof and all-solid-state battery

Abstract

The invention provides a high-nickel ternary precursor, a preparation method thereof and an all-solid-state battery. The method comprises the following steps: (1) performing a first coprecipitation reaction on a first nickel-cobalt-manganese ternary metal salt solution, a precipitator and a complexing agent, and collecting a first material after the particle size of particles in the first coprecipitation reaction reaches a required particle size range; (2) adding a second nickel-cobalt-manganese ternary metal salt solution into the system in the step (1) to carry out a second coprecipitation reaction, and collecting a second material after the particle size of the particles in the second coprecipitation reaction reaches the required particle size range; and (3) mixing the first material obtained in the step (1) and the second material obtained in the step (2) to obtain the high-nickel ternary precursor. By regulating and controlling the particle size and composition of the high-nickel ternary precursor, the structural stability and electrochemical performance of the high-nickel ternary positive electrode material are further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of positive electrode materials, and in particular relates to a high-nickel ternary precursor and a preparation method thereof, and an all-solid-state battery. Background Art

[0002] Liquid electrolytes have become the biggest constraint on the further development of lithium-ion batteries. The use of solid electrolytes instead of liquid electrolytes is expected to use positive and negative electrode materials with higher specific capacity, while completely solving the safety problems of lithium-ion batteries. Therefore, it is urgent to develop all-solid-state lithium batteries with high energy density, safety and long cycle life.

[0003] Among them, for negative electrode materials, compared with traditional graphite negative electrodes, lithium metal negative electrodes have higher theoretical specific capacity (3860mAh / g) and extremely low electrochemical potential, and are one of the ideal negative electrode materials; for positive electrode materials, high-nickel ternary positive electrode materials (such as NCM811, NCM922, etc.) are considered to be ideal choices for high energy density lithium-ion battery systems because of their high voltage, high specific capacity and cost-effectiveness. Therefore, when the above-mentioned lithium metal negative electrode materials and high-nickel ternary positive electrode materials are combined, the all-solid-state lithium battery can achieve the goal of having a higher energy density.

[0004] Based on this, the prior art discloses a technology for mixing large and small particles of high-nickel ternary positive electrode materials to improve the overall performance of all-solid-state batteries. Specifically, by mixing particles of different sizes, not only can a tighter stacking be achieved, thereby increasing the volume compaction density of the positive electrode material, but also the contact area between the positive electrode material and the solid electrolyte can be increased, which is conducive to improving the transmission efficiency of lithium ions, thereby improving the specific capacity and cycle stability of the all-solid-state battery. However, the particle size of the high-nickel ternary positive electrode material is large, which is prone to cracks and causes the structure of the positive electrode material to collapse. In addition, particles of positive electrode materials of different sizes often need to be separately subjected to lithium calcination treatment during sintering. The preparation process is complicated and the operation time is long, which greatly reduces the production efficiency and has a high manufacturing cost.

[0005] Therefore, in the art, there is an urgent need to develop a method for preparing high-nickel ternary positive electrode materials to solve the above problems while ensuring that they have good electrochemical properties. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a high-nickel ternary precursor and a preparation method thereof and an all-solid-state battery. The present invention further improves the structural stability and electrochemical performance of the high-nickel ternary cathode material by regulating the particle size and composition of the high-nickel ternary precursor.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing a high-nickel ternary precursor, the method comprising the following steps:

[0009] (1) subjecting a first nickel-cobalt-manganese ternary metal salt solution, a precipitant and a complexing agent to a first coprecipitation reaction, and collecting a first material after the particle size of particles produced by the first coprecipitation reaction reaches a desired particle size range;

[0010] (2) adding a second nickel-cobalt-manganese ternary metal salt solution to the system of step (1) to carry out a second coprecipitation reaction, and collecting a second material after the particle size of the particles produced by the second coprecipitation reaction reaches a desired particle size range;

[0011] (3) Mixing the first material obtained in step (1) and the second material obtained in step (2) to obtain the high-nickel ternary precursor.

[0012] On the one hand, the present invention precisely controls the proportion and distribution of precursor particles of different sizes in two co-precipitation stages, and further adjusts the chemical composition of precursor particles of different sizes, that is, reduces the nickel content of large-sized precursor particles, which helps to improve the structural stability of the particles during sintering and charging and discharging, and reduce the risk of cracks and structural collapse. At the same time, the present invention increases the content of small-sized precursor particles, and finally synthesizes a high-nickel ternary precursor with a high tap density, so that the high-nickel ternary precursor has good structural stability, cycle performance and high specific capacity. On the other hand, the present invention not only simplifies the process flow, but also reduces the production cost of high-nickel ternary positive electrode materials and improves their production efficiency.

[0013] Preferably, in step (1), the molar ratio of nickel element, cobalt element and manganese element in the first nickel-cobalt-manganese ternary metal salt solution is x:y:z, wherein x≥0.8, 0<y≤0.12, 0<z≤0.2, and x+y+z=1, preferably x≥0.9, x can be, for example, 0.8, 0.82, 0.85, 0.88, 0.9, 0.92, 0.94, 0.96, 0.98, etc.; y can be, for example, 0.05, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, etc.; z can be, for example, 0.05, 0.07, 0.08, 0.09, 0.1, 0.12, 0.15, 0.18, 0.2, etc.

[0014] In the present invention, the nickel salt containing the nickel element includes at least one of nickel chloride, nickel nitrate or nickel sulfate; the cobalt salt containing the cobalt element includes at least one of cobalt chloride, cobalt nitrate or cobalt sulfate; the manganese salt containing the manganese element includes at least one of manganese chloride, manganese nitrate or manganese sulfate.

[0015] Preferably, the total concentration of metal ions in the first nickel-cobalt-manganese ternary metal salt solution in step (1) is 1-5 mol / L, for example, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, 5 mol / L, etc.

[0016] Preferably, in step (1), the ratio of the feed rate of the first nickel-cobalt-manganese ternary metal salt solution to the feed rate of the precipitant is 1:2.

[0017] Preferably, the molar concentration of the precipitant in step (1) is 3-5 mol / L, for example, 3 mol / L, 3.2 mol / L, 3.5 mol / L, 3.8 mol / L, 4 mol / L, 4.2 mol / L, 4.5 mol / L, 4.8 mol / L, 5 mol / L, etc.

[0018] Preferably, the molar concentration of the complexing agent in step (1) is 8-12 mol / L, for example, it can be 8 mol / L, 8.5 mol / L, 9 mol / L, 9.5 mol / L, 10 mol / L, 10.5 mol / L, 11 mol / L, 11.5 mol / L, 12 mol / L, etc.

[0019] Preferably, the temperature of the first coprecipitation reaction in step (1) is 40-80°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C, etc.

[0020] Preferably, the time of the first coprecipitation reaction in step (1) is 40-80 h, for example, it can be 40 h, 45 h, 50 h, 55 h, 60 h, 65 h, 70 h, 75 h, 80 h, etc.

[0021] Preferably, the molar concentration of the complexing agent in the first coprecipitation reaction in step (1) is 0.1-1.5 mol / L, for example, it can be 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 0.8 mol / L, 1.0 mol / L, 1.2 mol / L, 1.5 mol / L, etc.

[0022] Preferably, the pH value of the first coprecipitation reaction in step (1) is 8-12, for example, it can be 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, etc.

[0023] Preferably, the required particle size range in step (1) is 1-5 μm, preferably 2-4 μm, for example, it can be 1 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2 μm, 2.2 μm, 2.5 μm, 2.8 μm, 3 μm, 3.2 μm, 3.5 μm, 3.8 μm, 4 μm, 4.2 μm, 4.5 μm, 4.8 μm, 5 μm, etc.

[0024] In the present invention, by regulating the molar ratio of nickel, cobalt and manganese in the first nickel-cobalt-manganese ternary metal salt solution in step (1) and the desired particle size range, a small-particle ultra-high nickel precursor is prepared, which is convenient for subsequent mixing with the large-particle high-nickel precursor with a core-shell structure prepared in step (2). If the particle size is small, fine powder will be present during the subsequent sintering. Otherwise, the purpose of filling the gaps between the large-particle high-nickel precursors and increasing the tap density of the high-nickel ternary precursor cannot be achieved.

[0025] Preferably, in step (2), the molar ratio of nickel element, cobalt element and manganese element in the second nickel-cobalt-manganese ternary metal salt solution is a:b:c, wherein a≥0.8, 0<b≤0.12, 0<c≤0.2, and a+b+c=1, preferably 0.8≤a≤0.9, a can be, for example, 0.8, 0.82, 0.85, 0.88, 0.9, etc.; b can be, for example, 0.05, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, etc.; c can be, for example, 0.05, 0.07, 0.08, 0.09, 0.1, 0.12, 0.15, 0.18, 0.2, etc.

[0026] In the present invention, by comprehensively regulating the molar ratios of nickel, cobalt and manganese in the first nickel-cobalt-manganese ternary metal salt solution and the second nickel-cobalt-manganese ternary metal salt solution, the small-particle ultra-high nickel precursor that is easy to crack prepared by the first coprecipitation reaction is located in the inner core part, and the large-particle high-nickel precursor with a core-shell structure with the small-particle ultra-high nickel precursor as the core is prepared by the second coprecipitation reaction, and the high-nickel precursor with a stable structure is located in the outer shell part, thereby improving the structural stability of the high-nickel ternary precursor; at the same time, the present invention preferably increases the feed flow rate of the second nickel-cobalt-manganese ternary metal salt solution in the second coprecipitation reaction, thereby increasing the growth rate of the outer shell part, so that the ultra-high nickel precursor with higher specific capacity accounts for a higher proportion.

[0027] In addition, the present invention mixes the small-particle ultra-high nickel precursor prepared by the first co-precipitation reaction with the large-particle high nickel precursor with a core-shell structure prepared by the second co-precipitation reaction in the later stage, so as to fill the gaps between the large-particle high nickel precursors and achieve the purpose of obtaining a high-nickel ternary precursor with a high tap density.

[0028] In the present invention, the nickel salt containing the nickel element includes at least one of nickel chloride, nickel nitrate or nickel sulfate; the cobalt salt containing the cobalt element includes at least one of cobalt chloride, cobalt nitrate or cobalt sulfate; the manganese salt containing the manganese element includes at least one of manganese chloride, manganese nitrate or manganese sulfate.

[0029] Preferably, the total concentration of metal ions in the second nickel-cobalt-manganese ternary metal salt solution in step (2) is 1-5 mol / L, for example, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, 5 mol / L.

[0030] Preferably, in step (2), the ratio of the feed rate of the second nickel-cobalt-manganese ternary metal salt solution to the feed rate of the first nickel-cobalt-manganese ternary metal salt solution is (1.5-2):1, for example, it can be 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, etc.

[0031] Preferably, in step (2), the ratio of the feed rate of the precipitant to the feed rate of the second nickel-cobalt-manganese ternary metal salt solution is 2:1.

[0032] Preferably, the temperature of the second coprecipitation reaction in step (2) is 40-80°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C, etc.

[0033] Preferably, the time of the second coprecipitation reaction in step (2) is 10-30 hours, for example, it can be 10 hours, 15 hours, 20 hours, 25 hours, 30 hours, etc.

[0034] Preferably, the molar concentration of the complexing agent in the second coprecipitation reaction in step (2) is 0.1-1.5 mol / L, for example, it can be 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 0.8 mol / L, 1.0 mol / L, 1.2 mol / L, 1.5 mol / L, etc.

[0035] Preferably, the pH value of the second coprecipitation reaction in step (2) is 8-11, for example, it can be 8, 8.2, 8.5, 8.8, 9, 9.2, 9.5, 9.8, 10, 10.2, 10.5, 10.8, 11, etc.

[0036] Preferably, the required particle size range in step (2) is greater than 5 μm and less than or equal to 15 μm, preferably 8-12 μm, for example, it can be 5.2 μm, 5.5 μm, 5.8 μm, 6 μm, 6.2 μm, 6.5 μm, 6.8 μm, 7 μm, 7.2 μm, 7.5 μm, 7.8 μm, 8 μm, 8.2 μm, 8.5 μm, 8.8 μm, 9 μm, 9.2 μm, 9. 5μm, 9.8μm, 10μm, 10.2μm, 10.5μm, 10.8μm, 11μm, 11.2μm, 11.5μm, 11.8μm, 12μm, 12.2μm , 12.5μm, 12.8μm, 13μm, 13.2μm, 13.5μm, 13.8μm, 14μm, 14.2μm, 14.5μm, 14.8μm, 15μm, etc.

[0037] In the present invention, by adjusting the desired particle size range described in step (2), a large-particle high-nickel precursor with a stable structure is prepared. If the particle size is too small, it cannot be sintered into the target polycrystalline positive electrode material, otherwise the structure is prone to collapse.

[0038] Preferably, in step (3), the mass ratio of the first material to the second material is (0.5-1):1, preferably (0.6-0.8):1, for example, it can be 0.5:1, 0.55:1, 0.6:1, 0.65:1, 0.7:1, 0.75:1, 0.8:1, 0.85:1, 0.9:1, 1:1, etc.

[0039] In the present invention, by regulating the mass ratio of the first material and the second material, the molar ratio of the transition metal elements in the high-nickel ternary precursor is made within an appropriate parameter range, thereby filling the gaps between the large-particle high-nickel precursor, thereby improving the tap density of the high-nickel ternary precursor. If the mass ratio is too low, the inner core of the small-particle ultra-high nickel precursor will have a smaller specific gravity and a lower nickel content. Otherwise, the outer shell portion of the large-particle high-nickel precursor with a core-shell structure will have a smaller specific gravity and its structure cannot be stabilized.

[0040] In the present invention, the step (3) further includes subjecting the first material and the second material to aging, washing and drying treatments respectively before mixing.

[0041] In the present invention, the temperature of the drying treatment is 90-200°C, for example, 90°C, 100°C, 120°C, 150°C, 180°C, 200°C, etc.

[0042] In a second aspect, the present invention provides a high-nickel ternary precursor, wherein the high-nickel ternary precursor is prepared by the method for preparing a high-nickel ternary precursor according to the first aspect.

[0043] Preferably, the particle size of the high-nickel ternary precursor is 6-12 μm, for example, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, etc.

[0044] Preferably, the tap density of the high nickel ternary precursor is not less than 2.1 g / cm 3 , for example, it can be 2.1 g / cm 3 , 2.2g / cm 3 , 2.3g / cm 3 , 2.4g / cm 3 , 2.5g / cm 3 , 2.6g / cm 3 , 2.7g / cm 3 wait.

[0045] In a third aspect, the present invention provides an all-solid-state battery, comprising a positive electrode, a negative electrode and a solid electrolyte, wherein the material of the positive electrode comprises a high-nickel ternary positive electrode material, and the high-nickel ternary positive electrode material is prepared from the high-nickel ternary precursor described in the second aspect.

[0046] In the present invention, the high-nickel ternary positive electrode material is exemplarily obtained by calcining the high-nickel ternary precursor according to the second aspect and a lithium source under an oxygen atmosphere.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The present invention provides a method for preparing a high-nickel ternary precursor. On the one hand, the present invention accurately controls the ratio and distribution of precursor particles of different sizes in two co-precipitation stages, and further adjusts the chemical composition of the precursor particles of different sizes, that is, reduces the nickel content of the large-sized precursor particles, which helps to improve the structural stability of the particles during sintering and charging and discharging, and reduce the risk of cracks and structural collapse. At the same time, the present invention increases the content of small-sized precursor particles, and finally synthesizes a high-nickel ternary precursor with a high tap density, so that the high-nickel ternary precursor has good structural stability, cycle performance and high specific capacity. On the other hand, the present invention not only simplifies the process flow, but also reduces the production cost of high-nickel ternary positive electrode materials and improves their production efficiency. DETAILED DESCRIPTION

[0049] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0050] Example 1

[0051] This embodiment provides a high-nickel ternary precursor and a preparation method thereof, the preparation method comprising the following steps:

[0052] (1) nickel sulfate, cobalt sulfate and manganese sulfate are fully mixed in a ratio of 0.92:0.03:0.05 in a molar ratio of nickel element, cobalt element and manganese element to prepare a first nickel-cobalt-manganese ternary metal salt solution with a total metal ion concentration of 3.5 mol / L; the first nickel-cobalt-manganese ternary metal salt solution, a sodium hydroxide solution with a molar concentration of 4 mol / L and an ammonia solution with a molar concentration of 10 mol / L are subjected to a first coprecipitation reaction in a reactor for 60 hours, wherein the feeding rate of the first nickel-cobalt-manganese ternary metal salt solution is 100 mol / h, the feeding rate of the sodium hydroxide solution is 202 mol / h, the feeding rate of the ammonia solution is 15 mol / h, the temperature of the first coprecipitation reaction is 60° C., the pH value of the first coprecipitation reaction is 11, and after the particle size of the particles of the first coprecipitation reaction reaches 3 μm, the first material is collected;

[0053] (2) nickel sulfate, cobalt sulfate and manganese sulfate are fully mixed in a ratio of 0.84:0.06:0.1 among the molar ratio of nickel element, cobalt element and manganese element to prepare a second nickel-cobalt-manganese ternary metal salt solution having a total metal ion concentration of 1.5 mol / L; the second nickel-cobalt-manganese ternary metal salt solution is added to a reactor for a second coprecipitation reaction for 20 hours, wherein the feed rate of the second nickel-cobalt-manganese ternary metal salt solution is 150 mol / h, the feed rate of the sodium hydroxide solution is 300 mol / h, the feed rate of the ammonia solution is 25 mol / h, the temperature of the second coprecipitation reaction is 60° C., the pH value of the second coprecipitation reaction is 10, and after the particle size of the particles of the second coprecipitation reaction reaches 10 μm, the second material is collected;

[0054] (3) The first material obtained in step (1) and the second material obtained in step (2) were aged, washed with deionized water, and dried at 120° C., respectively, and then mixed at a mass ratio of 0.7:1 to obtain the particle size of 8 μm and the tap density of 2.25 g / cm 3 High nickel ternary precursor.

[0055] Example 2

[0056] This embodiment provides a high-nickel ternary precursor and a preparation method thereof, the preparation method comprising the following steps:

[0057] (1) nickel sulfate, cobalt sulfate and manganese sulfate are fully mixed in a ratio of 0.92:0.03:0.05 in a molar ratio of nickel element, cobalt element and manganese element to prepare a first nickel-cobalt-manganese ternary metal salt solution with a total metal ion concentration of 3.5 mol / L; the first nickel-cobalt-manganese ternary metal salt solution, a sodium hydroxide solution with a molar concentration of 4 mol / L and an ammonia solution with a molar concentration of 10 mol / L are subjected to a first coprecipitation reaction in a reactor for 55 hours, wherein the feeding rate of the first nickel-cobalt-manganese ternary metal salt solution is 100 mol / h, the feeding rate of the sodium hydroxide solution is 202 mol / h, the feeding rate of the ammonia solution is 10 mol / h, the temperature of the first coprecipitation reaction is 60° C., the pH value of the first coprecipitation reaction is 10, and after the particle size of the particles of the first coprecipitation reaction reaches 2 μm, the first material is collected;

[0058] (2) nickel sulfate, cobalt sulfate and manganese sulfate are fully mixed in a ratio of 0.85:0.07:0.08 to obtain a second nickel-cobalt-manganese ternary metal salt solution having a total metal ion concentration of 1.5 mol / L; the second nickel-cobalt-manganese ternary metal salt solution is added to a reactor to carry out a second coprecipitation reaction for 15 hours, wherein the feed rate of the second nickel-cobalt-manganese ternary metal salt solution is 180 mol / h, the feed rate of the sodium hydroxide solution is 360 mol / h, the feed rate of the ammonia solution is 20 mol / h, the temperature of the second coprecipitation reaction is 60° C., the pH value of the second coprecipitation reaction is 9, and after the particle size of the second coprecipitation reaction reaches 8 μm, the second material is collected;

[0059] (3) The first material obtained in step (1) and the second material obtained in step (2) were aged, washed with deionized water, and dried at 120° C., respectively, and then mixed at a mass ratio of 0.6:1 to obtain the particle size of 7 μm and the tap density of 2.21 g / cm 3 High nickel ternary precursor.

[0060] Example 3

[0061] This embodiment provides a high-nickel ternary precursor and a preparation method thereof, the preparation method comprising the following steps:

[0062] (1) nickel sulfate, cobalt sulfate and manganese sulfate are fully mixed in a ratio of 0.92:0.03:0.05 in a molar ratio of nickel element, cobalt element and manganese element to prepare a first nickel-cobalt-manganese ternary metal salt solution with a total metal ion concentration of 3.5 mol / L; the first nickel-cobalt-manganese ternary metal salt solution, a sodium hydroxide solution with a molar concentration of 4 mol / L and an ammonia solution with a molar concentration of 10 mol / L are subjected to a first coprecipitation reaction in a reactor for 65 hours, wherein the feeding rate of the first nickel-cobalt-manganese ternary metal salt solution is 100 mol / h, the feeding rate of the sodium hydroxide solution is 202 mol / h, the feeding rate of the ammonia solution is 18 mol / h, the temperature of the first coprecipitation reaction is 60° C., the pH value of the first coprecipitation reaction is 12, and after the particle size of the particles of the first coprecipitation reaction reaches 4 μm, the first material is collected;

[0063] (2) nickel sulfate, cobalt sulfate and manganese sulfate are fully mixed in a molar ratio of nickel element, cobalt element and manganese element of 0.9:0.05:0.05 to prepare a second nickel-cobalt-manganese ternary metal salt solution with a total metal ion concentration of 1.5 mol / L; the second nickel-cobalt-manganese ternary metal salt solution is added to the reactor for a second coprecipitation reaction for 25 hours, wherein the feed rate of the second nickel-cobalt-manganese ternary metal salt solution is 190 mol / h, the feed rate of the sodium hydroxide solution is 380 mol / h, the feed rate of the ammonia solution is 25 mol / h, the temperature of the second coprecipitation reaction is 60° C., the pH value of the second coprecipitation reaction is 11, and after the particle size of the second coprecipitation reaction reaches 12 μm, the second material is collected;

[0064] (3) The first material obtained in step (1) and the second material obtained in step (2) were aged, washed with deionized water, and dried at 120° C., respectively, and then mixed at a mass ratio of 0.8:1 to obtain a particle size of 10 μm and a tap density of 2.23 g / cm 3 High nickel ternary precursor.

[0065] Example 4

[0066] This embodiment provides a high-nickel ternary precursor and a preparation method thereof, the preparation method comprising the following steps:

[0067] (1) nickel sulfate, cobalt sulfate and manganese sulfate are fully mixed in a ratio of 0.82:0.09:0.09 in a molar ratio of nickel element, cobalt element and manganese element to prepare a first nickel-cobalt-manganese ternary metal salt solution with a total metal ion concentration of 1 mol / L; the first nickel-cobalt-manganese ternary metal salt solution, a sodium hydroxide solution with a molar concentration of 3 mol / L and an ammonia solution with a molar concentration of 8 mol / L are subjected to a first coprecipitation reaction in a reactor for 40 hours, wherein the feeding rate of the first nickel-cobalt-manganese ternary metal salt solution is 100 mol / h, the feeding rate of the sodium hydroxide solution is 202 mol / h, the feeding rate of the ammonia solution is 10 mol / h, the temperature of the first coprecipitation reaction is 50° C., the pH value of the first coprecipitation reaction is 8, and after the particle size of the particles of the first coprecipitation reaction reaches 1 μm, the first material is collected;

[0068] (2) nickel sulfate, cobalt sulfate and manganese sulfate are fully mixed in a ratio of 0.8:0.1:0.1 in a molar ratio of nickel element, cobalt element and manganese element to prepare a second nickel-cobalt-manganese ternary metal salt solution with a total metal ion concentration of 1 mol / L; the second nickel-cobalt-manganese ternary metal salt solution is added to a reactor for a second coprecipitation reaction for 10 hours, wherein the feed rate of the second nickel-cobalt-manganese ternary metal salt solution is 150 mol / h, the feed rate of the sodium hydroxide solution is 300 mol / h, the feed rate of the ammonia solution is 15 mol / h, the temperature of the second coprecipitation reaction is 50° C., the pH value of the second coprecipitation reaction is 8, and after the particle size of the second coprecipitation reaction reaches 6 μm, the second material is collected;

[0069] (3) The first material obtained in step (1) and the second material obtained in step (2) were aged, washed with deionized water, and dried at 120° C., respectively, and then mixed at a mass ratio of 0.5:1 to obtain the particle size of 6 μm and the tap density of 2.18 g / cm 3 High nickel ternary precursor.

[0070] Example 5

[0071] This embodiment provides a high-nickel ternary precursor and a preparation method thereof, the preparation method comprising the following steps:

[0072] (1) nickel sulfate, cobalt sulfate and manganese sulfate are fully mixed in a ratio of 0.96:0.02:0.02 in a molar ratio of nickel element, cobalt element and manganese element to prepare a first nickel-cobalt-manganese ternary metal salt solution with a total metal ion concentration of 4 mol / L; the first nickel-cobalt-manganese ternary metal salt solution, a sodium hydroxide solution with a molar concentration of 5 mol / L and an ammonia solution with a molar concentration of 12 mol / L are subjected to a first coprecipitation reaction in a reactor for 70 hours, wherein the feeding rate of the first nickel-cobalt-manganese ternary metal salt solution is 100 mol / h, the feeding rate of the sodium hydroxide solution is 202 mol / h, the feeding rate of the ammonia solution is 20 mol / h, the temperature of the first coprecipitation reaction is 80° C., the pH value of the first coprecipitation reaction is 12, and after the particle size of the particles of the first coprecipitation reaction reaches 5 μm, the first material is collected;

[0073] (2) nickel sulfate, cobalt sulfate and manganese sulfate are fully mixed in a ratio of 0.92:0.04:0.04 in a molar ratio of nickel element, cobalt element and manganese element to prepare a second nickel-cobalt-manganese ternary metal salt solution with a total metal ion concentration of 4 mol / L; the second nickel-cobalt-manganese ternary metal salt solution is added to a reactor for a second coprecipitation reaction for 30 hours, wherein the feed rate of the second nickel-cobalt-manganese ternary metal salt solution is 200 mol / h, the feed rate of the sodium hydroxide solution is 400 mol / h, the feed rate of the ammonia solution is 30 mol / h, the temperature of the second coprecipitation reaction is 80° C., the pH value of the second coprecipitation reaction is 11, and after the particle size of the second coprecipitation reaction reaches 14 μm, the second material is collected;

[0074] (3) The first material obtained in step (1) and the second material obtained in step (2) were aged, washed with deionized water, and dried at 120° C., respectively, and then mixed in a mass ratio of 1:1 to obtain a particle size of 12 μm and a tap density of 2.19 g / cm 3 High nickel ternary precursor.

[0075] Example 6

[0076] The difference between this embodiment and embodiment 1 is that in step (1), after the particle size of the particles in the first coprecipitation reaction reaches 8 μm, the first material is collected, and the rest is the same as embodiment 1.

[0077] Example 7

[0078] The difference between this embodiment and embodiment 1 is that in step (2), after the particle size of the particles in the second coprecipitation reaction reaches 2 μm, the second material is collected, and the rest is the same as embodiment 1.

[0079] Example 8

[0080] The difference between this embodiment and embodiment 1 is that the mass ratio of the first material obtained in step (1) to the second material obtained in step (2) is 0.1:1, and the rest is the same as embodiment 1.

[0081] Example 9

[0082] The difference between this embodiment and embodiment 1 is that the mass ratio of the first material obtained in step (1) to the second material obtained in step (2) is 3:1, and the rest is the same as embodiment 1.

[0083] Example 10

[0084] The difference between this embodiment and embodiment 1 is that the molar ratio of nickel element, cobalt element and manganese element in step (1) is 0.84:0.06:0.1, and the molar ratio of nickel element, cobalt element and manganese element in step (2) is 0.92:0.03:0.05, and the rest is the same as embodiment 1.

[0085] Comparative Example 1

[0086] The difference between this comparative example and Example 1 is that step (2) and step (3) are not performed, and the rest are the same as Example 1.

[0087] Comparative Example 2

[0088] The difference between this comparative example and Example 1 is that step (1) and step (3) are not performed, and the rest are the same as Example 1.

[0089] Test conditions

[0090] The high nickel ternary precursors provided in Examples 1 to 10 and Comparative Examples 1 to 2 were subjected to a tap density test, and the test method was as follows:

[0091] The tap density of the high nickel ternary precursor provided in the examples and comparative examples was tested in accordance with "GB / T5162 Determination of the tap density of metal powders".

[0092] The high nickel ternary precursors provided in Examples 1 to 10 and Comparative Examples 1 to 2 were used to prepare positive electrode materials, and the positive electrode materials were assembled to obtain an all-solid-state lithium metal battery. The test method was as follows:

[0093] The high-nickel ternary precursor provided in the embodiment and the comparative example was mixed evenly with lithium carbonate in a total molar ratio of lithium element to nickel, cobalt and manganese of 1.12:1, and calcined at 800°C for 12 hours in an oxygen atmosphere to obtain the corresponding positive electrode material, and the positive electrode material was prepared into a positive electrode sheet, which was assembled with a metal lithium sheet and a Li6PS5Cl solid electrolyte to obtain an all-solid-state lithium metal battery with a current density of 0.5Acm -3. The voltage range is 2.5-4.3V.

[0094] The test results are shown in Table 1:

[0095] Table 1

[0096]

[0097] As can be seen from Table 1, the present invention accurately controls the proportion and distribution of precursor particles of different sizes in two coprecipitation stages, and further adjusts the chemical composition of precursor particles of different sizes, which helps to improve the structural stability of the particles during sintering and charging and discharging, and reduce the risk of cracks and structural collapse. In addition, the present invention preferably matches the particle size of the particles in the two coprecipitation stages, thereby increasing the tap density of the high-nickel ternary precursor, and the growth of the shell of the large-particle high-nickel precursor with a core-shell structure in the second coprecipitation stage affects the stability of the precursor structure, thereby affecting the capacity retention rate of the all-solid-state lithium metal battery.

[0098] The applicant declares that the present invention illustrates the process method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a high-nickel ternary precursor, characterized in that: The method comprises the following steps: (1) subjecting a first nickel-cobalt-manganese ternary metal salt solution, a precipitant and a complexing agent to a first coprecipitation reaction, and collecting a first material after the particle size of particles produced by the first coprecipitation reaction reaches a desired particle size range; (2) adding a second nickel-cobalt-manganese ternary metal salt solution to the system of step (1) to carry out a second coprecipitation reaction, and collecting a second material after the particle size of the particles produced by the second coprecipitation reaction reaches a desired particle size range; (3) Mixing the first material obtained in step (1) and the second material obtained in step (2) to obtain the high-nickel ternary precursor.

2. The method according to claim 1, characterized in that In step (1), the molar ratio of nickel, cobalt and manganese in the first nickel-cobalt-manganese ternary metal salt solution is x:y:z, wherein x≥0.8, 0<y≤0.12, 0<z≤0.2, and x+y+z=1, preferably x≥0.9; Preferably, in step (1), the total concentration of metal ions in the first nickel-cobalt-manganese ternary metal salt solution is 1-5 mol / L.

3. The method according to claim 1 or 2, characterized in that: In step (1), the ratio of the feed rate of the first nickel-cobalt-manganese ternary metal salt solution to the feed rate of the precipitant is 1:2; Preferably, the molar concentration of the precipitant in step (1) is 3-5 mol / L; Preferably, the molar concentration of the complexing agent in step (1) is 8-12 mol / L; Preferably, the temperature of the first coprecipitation reaction in step (1) is 40-80°C; Preferably, the first coprecipitation reaction time in step (1) is 40-80 hours; Preferably, the molar concentration of the complexing agent in the first coprecipitation reaction in step (1) is 0.1-1.5 mol / L; Preferably, the pH value of the first coprecipitation reaction in step (1) is 8-12.

4. The method according to any one of claims 1 to 3, characterized in that The desired particle size range in step (1) is 1-5 μm, preferably 2-4 μm.

5. The method according to any one of claims 1 to 4, characterized in that In step (2), the molar ratio of nickel, cobalt and manganese in the second nickel-cobalt-manganese ternary metal salt solution is a:b:c, wherein a≥0.8, 0<b≤0.12, 0<c≤0.2, and a+b+c=1, preferably 0.8≤a≤0.9; Preferably, in step (2), the total concentration of metal ions in the second nickel-cobalt-manganese ternary metal salt solution is 1-5 mol / L.

6. The method according to any one of claims 1 to 5, characterized in that In step (2), the ratio of the feed rate of the second nickel-cobalt-manganese ternary metal salt solution to the feed rate of the first nickel-cobalt-manganese ternary metal salt solution is (1.5-2):1; Preferably, in step (2), the ratio of the feed rate of the precipitant to the feed rate of the second nickel-cobalt-manganese ternary metal salt solution is 2:1; Preferably, the temperature of the second coprecipitation reaction in step (2) is 40-80°C; Preferably, the time of the second coprecipitation reaction in step (2) is 10-30 hours; Preferably, the molar concentration of the complexing agent in the second coprecipitation reaction in step (2) is 0.1-1.5 mol / L; Preferably, the pH value of the second coprecipitation reaction in step (2) is 8-11; Preferably, the desired particle size range in step (2) is greater than 5 μm and less than or equal to 15 μm, preferably 8-12 μm.

7. The method according to any one of claims 1 to 6, characterized in that In step (3), the mass ratio of the first material to the second material is (0.5-1):1, preferably (0.6-0.8):

1.

8. A high-nickel ternary precursor, characterized in that: The high-nickel ternary precursor is prepared by the method for preparing a high-nickel ternary precursor according to any one of claims 1-7.

9. The high-nickel ternary precursor according to claim 8, characterized in that: The particle size of the high nickel ternary precursor is 6-12 μm; Preferably, the tap density of the high nickel ternary precursor is not less than 2.1 g / cm 3 .

10. An all-solid-state battery, characterized in that: The all-solid-state battery comprises a positive electrode, a negative electrode and a solid electrolyte. The material of the positive electrode comprises a high-nickel ternary positive electrode material, and the high-nickel ternary positive electrode material is prepared from the high-nickel ternary precursor according to claim 8 or 9.

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