A precursor material and preparation method thereof

Abstract

The present invention relates to the technical field of new energy battery materials, and in particular to a precursor material and a preparation method thereof. The preparation method of the precursor material of the present invention comprises the following steps: under an inert atmosphere, a metal salt solution, an iron salt solution, a precipitant solution and a complexing agent solution are introduced into a reactor containing a base liquid for reaction to obtain a slurry; during the reaction process, when the reactor is full of material, the slurry is subjected to a solidification treatment; when the particle size of the solid particles in the slurry reaches the target value, the reaction is stopped to obtain the precursor material. The preparation method of the precursor material of the present invention improves the particle size distribution range of the precursor material, reduces the micropowder content, and improves the solid content and yield during the reaction process.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy battery materials, and in particular to a precursor material and a preparation method thereof. Background Art

[0002] With the deepening of the strategic layout of new energy, the rapid development of the new energy industry, and the rapid rise in the price of lithium-ion batteries, sodium-ion batteries have also ushered in very strong development.

[0003] Layered cathode materials for sodium-ion batteries have gradually emerged due to their advantages such as high energy density and long service life. The quality of precursor materials plays a decisive role in the electrical properties of cathode materials. Precursor materials with a large particle size range and less micropowder are of great significance for the development of high-stability energy-type sodium-ion batteries.

[0004] The current production methods of positive electrode precursor materials for sodium-ion batteries mainly rely on the continuous method and the intermittent method in the co-precipitation method. Among them, the product particles obtained by the continuous method are large and small, and their particle size distribution is wide, but the continuous method has the operation of feeding and discharging at the same time during the reaction process, resulting in low solid content and a higher number of micropowders, leading to the problem of low production yield. In the intermittent method, the material stays in the reactor for a longer time and has a higher chromium content. The products produced have fewer micropowder particles and a higher production yield, but the particle size distribution range of the products produced by the intermittent method is narrow.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The first object of the present invention is to provide a method for preparing a precursor material, which improves the particle size distribution range of the precursor material, reduces the content of micropowder particles, increases the solid content during the reaction, and improves the yield.

[0007] The second object of the present invention is to provide a precursor material as described above, which has the advantages of wide particle size distribution and less fine powder.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0009] The present invention provides a method for preparing a precursor material, comprising the following steps:

[0010] Under an inert atmosphere, a metal salt solution, an iron salt solution, a precipitant solution and a complexing agent solution are introduced into a reactor containing a base liquid to react and obtain a slurry; during the reaction process, when the reactor is full of material, the slurry is subjected to a solidification treatment; when the particle size of the solid particles in the slurry reaches a target value, the reaction is stopped to obtain the precursor material.

[0011] Furthermore, during the reaction process, the metal elements in the precursor material are distributed in a gradient by adjusting the feed rate of the metal salt solution and / or the iron salt solution.

[0012] Preferably, the interval time for adjusting the feeding speed is 5 to 35 hours.

[0013] Furthermore, the solid content of the slurry after the solidification treatment is 500-900 g / L.

[0014] Furthermore, the reaction temperature is 35-79° C., and the pH of the reaction system is 9.6-12.1.

[0015] Furthermore, when the D50 particle size of the solid particles in the slurry is 2-20 µm, the feeding is stopped and the reaction stops.

[0016] Preferably, the reaction time is 100-400 hours.

[0017] Furthermore, the metal salt solution includes at least one of a nickel salt solution, a cobalt salt solution, a copper salt solution, a manganese salt solution and a ferrous salt solution.

[0018] Preferably, the metal salt solution further includes at least one of an aluminum salt solution, a titanium salt solution, a zinc salt solution, a magnesium salt solution and a calcium salt solution.

[0019] Furthermore, the iron salt includes at least one of ferric sulfate, ferric nitrate, ferric chloride, ferric acetate and ammonium ferric sulfate.

[0020] Preferably, the precipitant comprises at least one of sodium hydroxide, potassium hydroxide, sodium carbonate and sodium oxalate.

[0021] Preferably, the complexing agent includes at least one of ammonia water, oxalic acid, citric acid and disodium ethylenediaminetetraacetate.

[0022] Furthermore, the total metal concentration in the metal salt solution is 0.8-2.7 mol / L.

[0023] Preferably, the concentration of the iron salt solution is 0.8-2.5 mol / L.

[0024] Preferably, the concentration of the precipitant solution is 3-12 mol / L.

[0025] Preferably, the concentration of the complexing agent solution is 0.5-12 mol / L.

[0026] The present invention also provides a precursor material, which is prepared by the method for preparing the precursor material as described above.

[0027] Furthermore, the chemical formula of the precursor material is Nix Co y Cu z Fe α Mn γ M β (OH)2; wherein M is at least one of Al, Ti, Zn, Mg and Ca; x+y+z+α+γ+β=1, 0≤x≤1, 0≤y≤1, 0≤z≤1, 0<α≤1, 0≤γ≤1, 0≤β≤1.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The preparation method of the precursor material of the present invention is a preparation method of a precursor with wide particle size distribution produced by an intermittent method. Relying on the advantages of high solid content and less fine powder in the intermittent reaction process, Fe is introduced into the reaction feed. 3+ , Fe 3+ The precipitation process of the precursor material has the characteristic of easily forming a small nucleus. The small nucleus is used as a growth point to effectively reduce the D50 particle size of the precursor material, thereby obtaining a precursor material with a wide particle size distribution. In addition, the preparation method has simple steps, few variables to be controlled, and high yield.

[0030] The present invention can prepare a precursor material having a wide particle size distribution and a concentration gradient distribution of metal elements by regulating the flow rate of the feed liquid during the reaction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 Ni of Example 1 of the present invention 0.2 Cu 0.1 Fe 0.3 Mn 0.4 FESEM image of (OH)2 precursor material.

[0033] Figure 2 Ni of Example 2 of the present invention 0.33 Fe 0.34 Mn 0.33 FESEM image of (OH)2 precursor material.

[0034] Figure 3 Ni of Comparative Example 1 of the present invention 0.2 Cu 0.1 Fe0.3 Mn 0.4 FESEM image of (OH)2 precursor material.

[0035] Figure 4 Ni of Comparative Example 2 of the present invention 0.33 Fe 0.34 Mn 0.33 FESEM image of (OH)2 precursor material. DETAILED DESCRIPTION

[0036] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0037] A precursor material and a preparation method thereof according to an embodiment of the present invention are described in detail below.

[0038] In some embodiments of the present invention, a method for preparing a precursor material is provided, comprising the following steps:

[0039] Under an inert atmosphere, a metal salt solution, an iron salt solution, a precipitant solution and a complexing agent solution are introduced into a reactor containing a base liquid to react and obtain a slurry; during the reaction process, when the reactor is full of material, the slurry is subjected to a solidification treatment; when the particle size of the solid particles in the slurry reaches the target value, the reaction is stopped to obtain a precursor material.

[0040] The present invention improves the co-precipitation method in the preparation method of precursor materials so that it has the advantages of less fine powder and high solid content of the intermittent method and the characteristics of a large particle size range of the continuous method, so that it can prepare precursor materials with a wide particle size range and less fine powder, and the preparation method has simple steps and high yield.

[0041] The present invention introduces a trivalent ferrous ion solution into the reaction feed, and utilizes the characteristic that the trivalent ferrous ion precipitation speed in an alkaline solution is greater than that of ferrous ions. When entering the reactor, the trivalent ferrous ion solution tends to form a single crystal nucleus with a small particle size. The small nucleus is easy to form during the precipitation process. The small nucleus is used as a growth point, and the D50 particle size of the product can be effectively reduced, so as to achieve the purpose of forming a precursor material with a wide particle size distribution under the process of an intermittent method.

[0042] The preparation method of the precursor material of the present invention has a long reaction time in the reactor, so that the obtained product has the characteristic of very little fine powder; the preparation method of the precursor material has simple steps and requires few variables to be controlled, and can effectively overcome the problems of frequent changes in reaction conditions, excessive fine powder particles, low solid content, etc. in industrial continuous production.

[0043] In some embodiments of the present invention, during the reaction process, the metal elements in the precursor material are distributed in a gradient by adjusting the feed rate of the metal salt solution and / or the iron salt solution.

[0044] In some embodiments of the present invention, during the reaction process, the feeding rate of the iron salt solution is adjusted so that the Fe element in the precursor material presents a gradient distribution.

[0045] In some embodiments of the present invention, the precursor material is a precursor material with a wide particle size distribution; preferably, the precursor material is a precursor material with a wide particle size distribution and a concentration gradient of the Fe element.

[0046] In some embodiments of the present invention, the interval time for adjusting the feeding speed is 5 to 35 hours; typically but not limiting, for example, the interval time for adjusting the feeding speed is 5 hours, 10 hours, 15 hours, 20 hours, 25 hours, 30 hours, 35 hours or a range consisting of any two thereof.

[0047] In some embodiments of the present invention, during the reaction process, the feed rate of the corresponding solution is adjusted according to the designed element concentration gradient distribution and the reaction time, and the reaction time after each adjustment of the feed rate is 5 to 35 hours.

[0048] For example, when the element with concentration gradient distribution is Fe, the feed rate of iron salt solution is adjusted during the reaction; when the element with concentration gradient distribution is Ni, the feed rate of Ni salt solution is adjusted during the reaction.

[0049] In some specific embodiments of the present invention, during the reaction process, whenever the reaction time increases by 5 to 35 hours, the real-time feed rate of the iron salt solution is adjusted to decrease or increase by 0.01 to 1 L / h.

[0050] In the preparation method of the precursor material of the present invention, the feeding rate of the iron salt solution is orderly adjusted during the feeding process, so that the precursor material with the Fe element presenting a concentration gradient distribution characteristic can be obtained, thereby overcoming the problem of difficulty in producing concentration gradient materials; the preparation method of the present invention can achieve a gradient distribution of the Fe element while producing products with a wide particle size distribution and less micropowder.

[0051] In some embodiments of the present invention, the inert gas includes at least one of N2, Ar, CO2 and He; preferably, the inert gas includes N2. Inert gas is introduced as a protective gas during the reaction to prevent oxidation.

[0052] In some embodiments of the present invention, the solid content of the slurry after the reinforcement treatment is 500~900g / L; typically but not limitatively, for example, the solid content of the slurry after the reinforcement treatment is 500g / L, 550g / L, 600g / L, 650g / L, 700g / L, 750g / L, 800g / L, 900g / L or a range consisting of any two of them.

[0053] In some embodiments of the present invention, the solidification treatment includes: when the reactor is full of material (full liquid level), starting the thickener to discharge part of the liquid in the reactor, and performing solidification treatment on the slurry in the reactor.

[0054] In the reaction process of the present invention, when the reactor is full of material, the thickener is turned on to carry out solidification treatment on the slurry in the reactor, so that the solid content of the slurry in the subsequent reaction process is maintained in the range of 500-900 g / L.

[0055] In some embodiments of the present invention, the reaction temperature is 35-79°C, and the pH of the reaction system is 9.6-12.1; typically but not limitatively, for example, the reaction temperature is 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or a range consisting of any two thereof; the pH of the reaction system is 9.6-12.1; typically but not limitatively, for example, the pH of the reaction system is 10, 10.5, 11, 11.5, 12 or a range consisting of any two thereof.

[0056] In some specific embodiments of the present invention, the reaction temperature is 50-75°C.

[0057] In some embodiments of the present invention, when the D50 particle size of the solid particles in the slurry is 2-20 µm, the feeding is stopped and the reaction is stopped.

[0058] In some embodiments of the present invention, the reaction time is 100 to 400 hours. The total reaction time may be 100 hours, 200 hours, 300 hours, 400 hours, or any two thereof.

[0059] In some embodiments of the present invention, the reaction time is 8 to 13 hours before the consolidation treatment is started.

[0060] In some embodiments of the present invention, the base solution includes a complexing agent and water; preferably, in the base solution, the concentration of the complexing agent is 0.3-4 mol / L.

[0061] In some embodiments of the present invention, the metal salt solution includes at least one of a nickel salt solution, a cobalt salt solution, a copper salt solution, a manganese salt solution, and a ferrous salt solution.

[0062] In some embodiments of the present invention, the metal salt solution further comprises at least one of an aluminum salt solution, a titanium salt solution, a zinc salt solution, a magnesium salt solution and a calcium salt solution.

[0063] In some embodiments of the present invention, the metal salt solution is an aqueous solution of a metal salt, and the metal salt is a soluble salt.

[0064] In some embodiments of the present invention, the metal salt comprises at least one of a nitrate, an acetate, a sulfate, and a chloride.

[0065] In some specific embodiments of the present invention, at least one of nickel salt, cobalt salt, manganese salt, copper salt and ferrous salt is weighed and mixed with pure water to prepare a metal salt solution with a total metal ion concentration of 0.8 to 2.7 mol / L. A trivalent iron salt is weighed and mixed with pure water to obtain an iron salt solution. Nickel salt, cobalt salt, manganese salt and copper salt are weighed according to the molar ratio of nickel, cobalt, manganese and copper elements in the precursor material. The sum of the iron element of the iron salt and the ferrous salt is weighed according to the molar ratio of the iron element in the precursor material.

[0066] In some embodiments of the present invention, the iron salt includes at least one of ferric sulfate, ferric nitrate, ferric chloride, ferric acetate, and ammonium ferric sulfate.

[0067] In some embodiments of the present invention, the precipitant comprises at least one of sodium hydroxide, potassium hydroxide, sodium carbonate and sodium oxalate; preferably, the precipitant comprises sodium hydroxide.

[0068] In some embodiments of the present invention, the complexing agent includes at least one of ammonia water, oxalic acid, citric acid and disodium ethylenediaminetetraacetate.

[0069] In some embodiments of the present invention, the total metal concentration in the metal salt solution is 0.8-2.7 mol / L; typically but not limiting, for example, the total metal concentration in the metal salt solution is 0.8 mol / L, 0.1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L or a range consisting of any two thereof.

[0070] In some embodiments of the present invention, the concentration of the iron salt solution is 0.8-2.5 mol / L; typically but not limiting, for example, the concentration of the iron salt solution is 0.8 mol / L, 0.1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L or a range consisting of any two thereof.

[0071] In some embodiments of the present invention, the concentration of the precipitant solution is 3-12 mol / L; typically but not limiting, for example, the concentration of the precipitant solution is 4 mol / L, 6 mol / L, 8 mol / L, 10 mol / L, 12 mol / L, or a range consisting of any two thereof. Preferably, the concentration of the precipitant solution is 3-8 mol / L.

[0072] In some embodiments of the present invention, the concentration of the complexing agent solution is 0.5-12 mol / L; typically but not limiting, for example, the concentration of the complexing agent solution is 0.5 mol / L, 2 mol / L, 4 mol / L, 6 mol / L, 8 mol / L, 10 mol / L, 12 mol / L or any two thereof. Preferably, the concentration of the complexing agent solution is 0.5-8 mol / L.

[0073] In some embodiments of the present invention, during the reaction, the feed rate of the metal salt solution is 10~50L / h; the feed rate of the iron salt solution is 0.5~10L / h; the feed rate of the complexing agent solution is 1~10L / h; and the feed rate of the precipitant solution is adjusted according to the pH of the reaction system.

[0074] In some embodiments of the present invention, a precursor material is also provided, which is prepared by the above-mentioned method for preparing the precursor material.

[0075] In some embodiments of the present invention, the chemical formula of the precursor material is Ni x Co y Cu z Fe α Mn γ M β (OH)2; wherein M is at least one of Al, Ti, Zn, Mg and Ca; x+y+z+α+γ+β=1, 0≤x≤1, 0≤y≤1, 0≤z≤1, 0<α≤1, 0≤γ≤1, 0≤β≤1.

[0076] In some embodiments of the present invention, the particle size pitch of the precursor material is 1.2~2.1.

[0077] In some embodiments of the present invention, a sodium ion battery is also provided, comprising the above-mentioned precursor material.

[0078] Precursor materials with a large particle size range and concentration gradient are beneficial to improving the stability and electrochemical performance of sodium-ion batteries.

[0079] Example 1

[0080] The Ni with wide particle size distribution and gradient Fe concentration provided in this embodiment 0.2 Cu 0.1Fe 0.3 Mn 0.4 The preparation method of (OH)2 precursor material comprises the following steps:

[0081] S1. Nickel sulfate, copper sulfate, ferrous sulfate and manganese sulfate were mixed with pure water according to the molar ratio of metal ions Ni:Cu:Fe:Mn=20:10:22:40 to prepare solution A with a total metal concentration of 2.5 mol / L; ferric sulfate was mixed with pure water to prepare solution B with a concentration of 1 mol / L, and the molar ratio of Fe in solution B to Ni in solution A was 8:20; sodium hydroxide was mixed with water to prepare solution C with a concentration of 5.5 mol / L; oxalic acid was mixed with water to prepare solution D with a concentration of 3.5 mol / L;

[0082] S2. Add an aqueous solution of oxalic acid as a base liquid to the reactor, wherein the concentration of oxalic acid in the base liquid is 0.8 mol / L; introduce nitrogen into the reactor in advance and keep it in a stirring and dispersing state; introduce solution A, solution B, solution C and solution D into the reactor at the same time for reaction, wherein the feed flow rates of solution A, solution B and solution D are 20 L / h, 1.4 L / h and 3 L / h respectively, and the feed flow rate of solution C is controlled to make the pH of the reaction system 10-10.2, and the reaction temperature is 57-62°C; after 9 hours of reaction, the reactor is full of material (full liquid level), the thickener device is turned on to allow the slurry in the reactor to enter the thickener, and the clearing valve is opened to carry out solidification treatment on the slurry to maintain the solid content of the slurry at 650-730 g / L;

[0083] S3. During the reaction, the feed rate of solution B is adjusted, and the feed rates of other solutions remain unchanged. Every time the reaction time increases by 10 hours, the real-time feed rate of solution B is increased by 0.2L / h. During the feeding, the usage of solution A and solution B needs to be monitored to ensure that when the target particle size is reached, the ratio of metal ions in the precursor material is consistent with the target component.

[0084] After the reaction continued for 260 hours, the D50 particle size of the solid particles in the reaction liquid reached the target particle size of 10 μm, the feeding was stopped, the reaction was stopped, and then the reaction liquid in the reactor was separated into solid and liquid to obtain a precursor material with a D50 of 10 μm, a Fe concentration gradient distribution, and a wide particle size distribution.

[0085] Example 2

[0086] The Ni with wide particle size distribution and gradient Fe concentration provided in this embodiment 0.33 Fe 0.34 Mn 0.33 The preparation method of (OH)2 precursor material comprises the following steps:

[0087] S1. Mix nickel sulfate, ferrous sulfate and manganese sulfate with pure water in a molar ratio of metal ions Ni:Fe:Mn=33:24:33 to prepare a solution A with a total metal concentration of 2.5 mol / L; mix ferric acetate with pure water to prepare a solution B with a concentration of 1 mol / L, and the molar ratio of Fe in solution B to Ni in solution A is 10:33; mix sodium hydroxide with water to prepare a solution C with a concentration of 5.5 mol / L; mix oxalic acid with water to prepare a solution D with a concentration of 3.5 mol / L;

[0088] S2. Add an aqueous solution of oxalic acid as a base liquid to the reactor, wherein the concentration of oxalic acid in the base liquid is 0.8 mol / L; introduce nitrogen into the reactor in advance and keep it in a stirring and dispersing state; introduce solution A, solution B, solution C and solution D into the reactor at the same time for reaction, wherein the feed flow rates of solution A, solution B and solution D are 20 L / h, 2 L / h and 3.1 L / h respectively, and the pH of the reaction system is controlled to be 10.5-10.9 by controlling the feed flow rate of solution C, and the reaction temperature is 58-62°C; after 11 hours of reaction, the reactor is full of material (full liquid level), the thickener device is turned on to allow the slurry in the reactor to enter the thickener, and the clearing valve is opened to carry out solidification treatment on the slurry to maintain the solid content of the slurry at 630-780 g / L;

[0089] S3. During the reaction, the feed rate of solution B is adjusted, and the feed rates of other solutions remain unchanged. Every time the reaction time increases by 12h, the real-time feed rate of solution B is increased by 0.3L / h. During the feeding, the usage of solution A and solution B needs to be monitored to ensure that when the target particle size is reached, the ratio of metal ions in the precursor material is consistent with the target component.

[0090] After the reaction continued for 250 hours, the D50 particle size of the solid particles in the reaction liquid reached the target particle size of 7 μm, the feeding was stopped, the reaction was stopped, and then the reaction liquid in the reactor was separated into solid and liquid to obtain a precursor material with a D50 of 7 μm, a Fe concentration gradient distribution, and a wide particle size distribution.

[0091] Example 3

[0092] The Ni with wide particle size distribution and gradient Fe concentration provided in this embodiment 0.2 Mn 0.75 Fe 0.05 The preparation method of (OH)2 precursor material comprises the following steps:

[0093] S1. Mix nickel sulfate and manganese sulfate with pure water in a molar ratio of metal ions Ni:Mn=20:75 to prepare a solution A with a total metal concentration of 2.5 mol / L; mix ferric nitrate with pure water to prepare a solution B with a concentration of 1 mol / L, and the molar ratio of Fe in solution B to Ni in solution A is 5:20; mix sodium hydroxide with water to prepare a solution C with a concentration of 5.5 mol / L; prepare an ammonia solution with a concentration of 3.5 mol / L as solution D;

[0094] S2. Add 0.8 mol / L ammonia solution into the reactor as the base liquid; introduce nitrogen into the reactor in advance and keep it in a stirring and dispersing state; introduce solution A, solution B, solution C and solution D into the reactor at the same time for reaction, wherein the feed flow rates of solution A, solution B and solution D are 20 L / h, 2 L / h and 2 L / h respectively, and the pH of the reaction system is 9.7-10 and the reaction temperature is 70-75°C by controlling the feed flow rate of solution C; after 13 hours of reaction, the reactor is full of material (full liquid level), the thickener device is turned on to allow the slurry in the reactor to enter the thickener, and the clearing valve is opened to carry out solidification treatment on the slurry to maintain the solid content of the slurry at 600-770 g / L;

[0095] S3. During the reaction, the feed rate of solution B is adjusted, and the feed rates of other solutions remain unchanged. Every time the reaction time increases by 30h, the real-time feed rate of solution B is increased by 0.5L / h. During the feeding, the usage of solution A and solution B needs to be monitored to ensure that when the target particle size is reached, the ratio of metal ions in the precursor material is consistent with the target component.

[0096] After the reaction continued for 270 hours, the D50 particle size of the solid particles in the reaction liquid reached the target particle size of 11 μm, the feeding was stopped, the reaction was stopped, and then the reaction liquid in the reactor was separated into solid and liquid to obtain a precursor material with a D50 of 11 μm, a Fe concentration gradient distribution, and a wide particle size distribution.

[0097] Example 4

[0098] The Ni with wide particle size distribution and gradient Fe concentration provided in this embodiment 0.75 Co 0.05 Mn 0.15 Fe 0.05 The preparation method of (OH)2 precursor material comprises the following steps:

[0099] S1. Mix nickel sulfate, cobalt sulfate and manganese sulfate with pure water in a molar ratio of metal ions Ni:Co:Mn=75:5:15 to prepare solution A with a total metal concentration of 2 mol / L; mix ferric sulfate with pure water to prepare solution B with a concentration of 1.2 mol / L, and the molar ratio of Fe in solution B to Ni in solution A is 5:75; mix sodium hydroxide with water to prepare solution C with a concentration of 5.5 mol / L; prepare ammonia solution with a concentration of 3.5 mol / L as solution D;

[0100] S2. Add 0.3 mol / L ammonia solution into the reactor as the base liquid; introduce nitrogen into the reactor in advance and keep it in a stirring and dispersing state; introduce solution A, solution B, solution C and solution D into the reactor at the same time for reaction, wherein the feed flow rates of solution A, solution B and solution D are 20 L / h, 0.8 L / h and 2 L / h respectively, and the pH of the reaction system is 10.7 and the reaction temperature is 50-54°C by controlling the feed flow rate of solution C; after 12 hours of reaction, the reactor is full of material (full liquid level), the thickener device is turned on to allow the slurry in the reactor to enter the thickener, and the clearing valve is opened to carry out solidification treatment on the slurry to maintain the solid content of the slurry at 700-790 g / L;

[0101] S3. During the reaction, the feed rate of solution B was adjusted, and the feed rates of other solutions remained unchanged. Every time the reaction time increased by 32h, the real-time feed rate of solution B was increased by 0.5L / h. The usage of solution A and solution B needed to be monitored during feeding to ensure that when the target particle size was reached, the ratio of metal ions in the precursor material was consistent with the target component.

[0102] After the reaction continued for 280 hours, the D50 particle size of the solid particles in the reaction liquid reached the target particle size of 10 μm, the feeding was stopped, the reaction was stopped, and then the reaction liquid in the reactor was separated into solid and liquid to obtain a precursor material with a D50 of 10 μm, a Fe concentration gradient distribution, and a wide particle size distribution.

[0103] Example 5

[0104] The Cu with wide particle size distribution and gradient Fe concentration provided in this embodiment 0.2 Fe 0.3 Mn 0.5 The preparation method of (OH)2 precursor material comprises the following steps:

[0105] S1. Copper sulfate, ferrous sulfate and manganese sulfate were mixed with pure water according to the molar ratio of metal ions Cu:Fe:Mn=20:23:50 to prepare solution A with a total metal concentration of 2 mol / L; ammonium ferric sulfate was mixed with pure water to prepare solution B with a concentration of 1 mol / L, and the molar ratio of Fe in solution B to Cu in solution A was 7:20; sodium hydroxide was mixed with water to prepare solution C with a concentration of 5.5 mol / L; oxalic acid was mixed with water to prepare solution D with a concentration of 3.5 mol / L;

[0106] S2. Add an aqueous solution of oxalic acid as a base liquid to the reactor, wherein the concentration of oxalic acid in the base liquid is 0.8 mol / L; introduce nitrogen into the reactor in advance and keep it in a stirring and dispersing state; introduce solution A, solution B, solution C and solution D into the reactor at the same time for reaction, wherein the feed flow rates of solution A, solution B and solution D are 20 L / h, 2 L / h and 3.1 L / h, respectively, and the pH of the reaction system is 11.3 and the reaction temperature is 58-62°C by controlling the feed flow rate of solution C; after 10 hours of reaction, the reactor is full of material (full liquid level), the thickener device is turned on to allow the slurry in the reactor to enter the thickener, and the clearing valve is opened to carry out solidification treatment on the slurry to maintain the solid content of the slurry at 500-580 g / L;

[0107] S3. During the reaction, the feed rate of solution B is adjusted, and the feed rates of other solutions remain unchanged. Every time the reaction time increases by 9h, the real-time feed rate of solution B is increased by 0.2L / h. During the feeding, the usage of solution A and solution B needs to be monitored to ensure that when the target particle size is reached, the ratio of metal ions in the precursor material is consistent with the target component.

[0108] After the reaction continued for 100 hours, the D50 particle size of the solid particles in the reaction liquid reached the target particle size of 5 μm, the feeding was stopped, the reaction was stopped, and then the reaction liquid in the reactor was separated into solid and liquid to obtain a precursor material with a D50 of 5 μm, a Fe concentration gradient distribution, and a wide particle size distribution.

[0109] Example 6

[0110] The Ni with wide particle size distribution and gradient Fe concentration provided in this embodiment 0.1 Co 0.05 Cu 0.1 Fe 0.25 Mn 0.5 The preparation method of (OH)2 precursor material comprises the following steps:

[0111] S1. Mix nickel sulfate, cobalt sulfate, copper sulfate, ferrous sulfate and manganese sulfate with pure water in a molar ratio of metal ions Ni:Co:Cu:Fe:Mn=10:5:10:17:50 to prepare solution A with a total metal concentration of 2.5 mol / L; mix ammonium ferric sulfate with pure water to prepare solution B with a concentration of 1 mol / L, and the molar ratio of Fe in solution B to Ni in solution A is 8:10; mix sodium hydroxide with water to prepare solution C with a concentration of 5.5 mol / L; mix oxalic acid with water to prepare solution D with a concentration of 3.5 mol / L;

[0112] S2. Add an aqueous solution of oxalic acid as a base liquid to the reactor, wherein the concentration of oxalic acid in the base liquid is 0.8 mol / L; introduce nitrogen into the reactor in advance and keep it in a stirring and dispersing state; introduce solution A, solution B, solution C and solution D into the reactor at the same time for reaction, wherein the feed flow rates of solution A, solution B and solution D are 20 L / h, 6.1 L / h and 2.5 L / h respectively, and the pH of the reaction system is 10.8 and the reaction temperature is 65-68°C by controlling the feed flow rate of solution C; after the reactor is full of material (full liquid level) after 9 hours of reaction, open the thickener device to allow the slurry in the reactor to enter the thickener, and open the clearing valve to carry out solidification treatment on the slurry to maintain the solid content of the slurry at 780-880 g / L;

[0113] S3. During the reaction, the feed rate of solution B was adjusted, and the feed rates of other solutions remained unchanged. Every time the reaction time increased by 26h, the real-time feed rate of solution B was increased by 0.35L / h. The usage of solution A and solution B needed to be monitored during feeding to ensure that when the target particle size was reached, the ratio of metal ions in the precursor material was consistent with the target component.

[0114] After the reaction continued for 337 hours, the D50 particle size of the solid particles in the reaction liquid reached the target particle size of 15 μm, the feeding was stopped, the reaction was stopped, and then the reaction liquid in the reactor was separated into solid and liquid to obtain a precursor material with a D50 of 15 μm, a Fe concentration gradient distribution, and a wide particle size distribution.

[0115] Comparative Example 1

[0116] The Ni 0.2 Cu 0.1 Fe 0.3 Mn 0.4 The preparation method of (OH) precursor material comprises the following steps:

[0117] S1. Nickel sulfate, copper sulfate, ferrous sulfate and manganese sulfate were mixed with pure water according to the molar ratio of metal ions Ni:Cu:Fe:Mn=20:10:30:40 to prepare solution A with a total metal concentration of 2.5 mol / L; sodium hydroxide was mixed with water to prepare solution C with a concentration of 5.5 mol / L; oxalic acid was mixed with water to prepare solution D with a concentration of 3.5 mol / L;

[0118] S2. Add an aqueous solution of oxalic acid as a base liquid to the reactor, wherein the concentration of oxalic acid in the base liquid is 0.8 mol / L; introduce nitrogen into the reactor in advance and keep it in a stirring and dispersing state; introduce solution A, solution C and solution D into the reactor at the same time for reaction, wherein the feed flow rates of solution A and solution D are 20 L / h and 3 L / h, respectively, and the feed flow rate of solution C is controlled to make the pH of the reaction system 10-10.2, and the reaction temperature is 57-62°C; after 9 hours of reaction, the reactor is full of material (full liquid level), the thickener device is turned on to allow the slurry in the reactor to enter the thickener, and the clearing valve is opened to solidify the slurry to ensure that no liquid overflow occurs;

[0119] S3. The amount of solution A and solution B used needs to be monitored during feeding to ensure that when the target particle size is reached, the ratio of metal ions in the precursor material is consistent with the target component;

[0120] After the reaction continued for 53 hours, the D50 particle size of the solid particles in the reaction liquid reached the target particle size of 10 μm, the feeding was stopped, the reaction was stopped, and then the reaction liquid in the reactor was separated into solid and liquid to obtain a precursor material with a D50 of 10 μm.

[0121] Comparative Example 2

[0122] The Ni provided in this comparative example 0.33 Fe 0.34 Mn 0.33 The preparation method of (OH)2 precursor material comprises the following steps:

[0123] S1. Nickel sulfate, ferrous sulfate and manganese sulfate were mixed with pure water in a molar ratio of metal ions Ni:Fe:Mn=33:34:33 to prepare a solution A with a total metal concentration of 2.5 mol / L; sodium hydroxide was mixed with water to prepare a solution C with a concentration of 5.5 mol / L; oxalic acid was mixed with water to prepare a solution D with a concentration of 3.5 mol / L;

[0124] S2. Add an aqueous solution of oxalic acid as a base liquid to the reactor, wherein the concentration of oxalic acid in the base liquid is 0.8 mol / L; introduce nitrogen into the reactor in advance and keep it in a stirring and dispersing state; introduce solution A, solution C and solution D into the reactor at the same time for reaction, wherein the feed flow rates of solution A and solution D are 20 L / h and 3.1 L / h, respectively, and the pH of the reaction system is controlled to be 10.5-10.9 by controlling the feed flow rate of solution C, and the reaction temperature is 58-62°C; after the reactor is full of material (full liquid level) after 11 hours of reaction, open the thickener device to allow the slurry in the reactor to enter the thickener, and open the clearing valve to solidify the slurry to ensure that there is no liquid overflow;

[0125] S3. The amount of solution A and solution B used needs to be monitored during feeding to ensure that when the target particle size is reached, the ratio of metal ions in the precursor material is consistent with the target component;

[0126] After the reaction continued for 43 hours, the D50 particle size of the solid particles in the reaction liquid reached the target particle size of 7 μm, the feeding was stopped, the reaction was stopped, and then the reaction liquid in the reactor was separated into solid and liquid to obtain a precursor material with a D50 of 7 μm.

[0127] Test Example 1

[0128] The precursor materials obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were tested by scanning electron microscopy, and the results are as follows: Figure 1 , Figure 2 , Figure 3 and Figure 4 shown.

[0129] Figure 1 and Figure 2 The FESEM images of the precursor materials of Example 1 and Example 2 of the present invention are shown respectively. Figure 1 and Figure 2 It can be seen that the particle sizes of the precursor materials of Example 1 and Example 2 are different, there are a large number of large and small particles, and the particle size distribution is wide. The preparation method of the present invention can continuously generate small crystal nuclei through the characteristics of rapid reaction of trivalent iron and hydroxide during the reaction process, which plays a role in increasing the particle size distribution range and can obtain a precursor material with a wide particle size distribution.

[0130] Figure 3 and Figure 4 The FESEM images of the precursor materials of Comparative Example 1 and Comparative Example 2 of the present invention are shown respectively. Figure 3 and Figure 4 It can be seen that the particle sizes of the precursor materials of Comparative Example 1 and Comparative Example 2 are not much different, and a product with a wide particle size distribution cannot be obtained by a conventional intermittent method.

[0131] In addition, thanks to the control of different flow rates of the trivalent iron ion solution during feeding, the products obtained in Examples 1 to 6 have the characteristic that the distribution of metal elements presents a concentration gradient distribution.

[0132] The test shows that the particles of the precursor materials prepared in the other Examples 3 to 6 are all of wide particle size and distributed in large and small sizes, while the specific Fe element exhibits the characteristics of concentration gradient distribution due to the difference in reagent feed flow rate.

[0133] The particle size of the precursor materials of Examples 1-2 and Comparative Examples 1-2 was characterized, and the results are shown in Table 1.

[0134] Table 1

[0135]

[0136] As can be seen from Table 1, the introduction of trivalent iron ions can effectively produce small particles, which has the effect of increasing the particle size. In addition, the comparison results of solid content at the end of the reaction also verify that the present invention can obtain a product with a high solid content through an intermittent process.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a precursor material, characterized in that: The steps include: S1, mixing ferrous salt, and at least one of nickel salt, cobalt salt, manganese salt and copper salt with pure water to prepare solution A with a total metal ion concentration of 0.8-2.7 mol / L; mixing trivalent iron salt with pure water to prepare solution B with a concentration of 0.8-2.5 mol / L; mixing precipitant with water to prepare solution C with a concentration of 3-12 mol / L; mixing complexing agent with water to prepare solution D with a concentration of 0.5-12 mol / L; S2, add the aqueous solution of the complexing agent as the base liquid to the reactor, the concentration of the complexing agent in the base liquid is 0.3-4 mol / L; introduce inert gas into the reactor in advance and keep stirring; introduce solution A, solution B, solution C and solution D into the reactor at the same time for reaction, wherein the feed flow rates of solution A, solution B and solution D are 10-50 L / h, 0.5-10 L / h and 1-10 L / h respectively, and the pH of the reaction system is 9.6-12.1 and the reaction temperature is 50-75°C by controlling the feed flow rate of solution C; after reacting for 8-13 hours, the reactor is full of material, the thickener device is turned on to allow the slurry in the reactor to enter the thickener, and the clearing valve is opened to carry out solidification treatment on the slurry to maintain the solid content of the slurry at 500-900 g / L; S3. During the reaction, the feed rate of solution B is adjusted, and the feed rates of other solutions remain unchanged. Whenever the reaction time increases by 5 to 35 hours, the real-time feed rate of solution B is increased by 0.01 to 1 L / h. During the feeding, the usage of solution A and solution B needs to be monitored to ensure that when the target particle size is reached, the ratio of metal ions in the precursor material is consistent with the target component. After the reaction continues for 100 to 400 hours, when the D50 particle size of the solid particles in the reaction liquid reaches the target particle size of 2 to 20 µm, the feeding is stopped, the reaction is stopped, and then the reaction liquid in the reactor is separated into solid and liquid to obtain the precursor material.

2. The method for preparing a precursor material according to claim 1, characterized in that: The ferric iron salt includes at least one of ferric sulfate, ferric nitrate, ferric chloride, ferric acetate and ammonium ferric sulfate.

3. The method for preparing a precursor material according to claim 1, characterized in that: The precipitant includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate and sodium oxalate.

4. The method for preparing a precursor material according to claim 1, characterized in that: The complexing agent includes at least one of ammonia water, oxalic acid, citric acid and disodium ethylenediaminetetraacetate.

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