Sodium-ion battery quaternary precursor, preparation method and application thereof

Abstract

The application belongs to the field of sodium ion battery related materials, and discloses a sodium ion battery quaternary precursor, a preparation method and application thereof, the sodium ion battery quaternary precursor comprises a core and a shell layer coated on at least part of the surface of the core; the chemical formula of the core is Ni x1 Zn y1 Fe z1 Mn 1‑x1‑y1‑z1 (OH)2, wherein 0.1<=x1<=0.4, 0<=y1<=0.03, 0.1<=z1<=0.5, x1+y1+z1<1; the chemical formula of the shell layer is Ni x2 Zn y2 Fe z2 Mn 1‑x2‑y21‑z2 (OH)2, wherein 0.1<=x2<=0.4, 0.04<=y2<=0.12, 0.1<=z2<=0.5, x2+y2+z2<1; the tap density of the sodium ion battery quaternary precursor is 1.4-1.8 g / cm 3 The precursor has a compact structure, high tap density and good product consistency.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of sodium ion battery related materials, and relates to a preparation process of a precursor, in particular to a sodium ion battery quaternary precursor and a preparation method and application thereof. BACKGROUND

[0002] The sodium ion battery is a kind of secondary battery, which has the same working principle and similar battery components as the lithium ion battery. In the case that lithium resources are facing shortage, the sodium ion battery is concerned due to the advantages of abundant sodium resources, low cost and good comprehensive performance, and has good application prospect in the fields of energy storage and power battery.

[0003] The sodium ion battery cathode material can be divided into layered oxide type, polyanion type and prussian blue type, among which the layered oxide is the most widely used, and the structural composition of the precursor has a great influence on the performance of the layered oxide, and further influences the electrochemical performance of the sodium ion battery.

[0004] In the study of the applicable system of transition metals in the layered oxide, it is found that proper doping of different elements in the nickel-iron-manganese-based sodium ion battery precursor can improve the rate performance and cycle performance of the sodium ion battery, for example, doping Cu can improve the air stability, cycle stability and rate performance of the material; doping Zn can provide vacancies for the insertion of sodium ions, ensuring the rate performance of the material.

[0005] In the prior art, other elements are usually doped in the precursor by a co-precipitation process, but simultaneous co-precipitation of multiple metal elements can easily lead to uneven distribution of elements, and partial metal elements can easily segregate during the co-precipitation process, resulting in low tap density and poor morphology of the precursor. SUMMARY

[0006] In view of the defects and deficiencies in the prior art, in a first aspect, the application provides a sodium ion battery quaternary precursor; in a second aspect, the application provides a preparation method of the sodium ion battery quaternary precursor; in a third aspect, the application provides a cathode material; and in a fourth aspect, the application provides a battery.

[0007] In a first aspect, the application provides a sodium ion battery quaternary precursor, which comprises a core and a shell layer coated on at least part of the surface of the core; the chemical formula of the core is Ni x1 Zn y1 Fe z1 Mn 1-x1-y1-z1 (OH)2, wherein 0.1≤x1≤0.4, 0≤y1≤0.03, 0.1≤z1≤0.5, and x1+y1+z1<1; the chemical formula of the shell layer is Ni x2 Zn y2 Fe z2 Mn1-x2-y21-z2 (OH)2, wherein 0.1≤x2≤0.4, 0.04≤y2≤0.12, 0.1≤z2≤0.5, x2+y2+z2<1; the tap density of the sodium-ion battery quaternary precursor is 1.4~1.8g / cm 3 .

[0008] Preferably, the primary particles of the sodium-ion battery quaternary precursor are orderly intercalated flaky; the secondary particles of the sodium-ion battery quaternary precursor are spherical or spheroidal.

[0009] In a second aspect, the present application provides a preparation method of the above-mentioned sodium-ion battery quaternary precursor, comprising the following steps:

[0010] Step 1, mixing nickel salt, iron salt, manganese salt, zinc salt and first antioxidant solution to obtain metal salt mixed solution A; mixing nickel salt, iron salt, manganese salt, zinc salt and first antioxidant solution to obtain metal salt mixed solution B; wherein the concentration of zinc salt in metal salt mixed solution B is higher than that in solution A;

[0011] Step 2, continuously feeding metal salt mixed solution A, precipitant solution and complexing agent solution into the bottom liquid of the reaction kettle under inert atmosphere to prepare the core, wherein the preparation of the core includes a first stage and a second stage, and the pH value in the first stage reaction system is 0.5~1.0 higher than that in the second stage reaction system; in the first stage, the pH value of the reaction system is adjusted to 11.0~12.0, and after a certain period of reaction, it enters the second stage, and then the pH value of the reaction system is adjusted to 10.5~11.0, and a certain period of reaction is carried out;

[0012] Step 3, stop feeding metal salt mixed solution A, continuously feed metal salt mixed solution B, precipitant solution and complexing agent solution into the bottom liquid of the reaction kettle, adjust the pH value of the reaction system to 9~10, and react for a certain period of time to obtain slurry;

[0013] Step 4, solid-liquid separation of the slurry prepared in step 3, then solid-liquid separation, washing, drying, to obtain the sodium-ion battery quaternary precursor material.

[0014] Preferably, the nickel salt, iron salt, manganese salt, zinc salt are each independently any one or two or more of sulfate, nitrate, acetate, chlorate.

[0015] Preferably, the precipitant solution is any one or two or more of sodium hydroxide solution, potassium hydroxide solution; further preferably, the precipitant solution is sodium hydroxide solution.

[0016] Preferably, the concentration of the precipitant solution is 8~12mol / L.

[0017] Preferably, the complexing agent solution is any one or more of sodium citrate solution, sodium fluoride solution, hydroxyethyl ethylenediamine triacetic acid solution, sodium gluconate solution, ethylenediamine tetraacetic acid solution, sodium ethylenediamine tetraacetic acid solution, ammonia water; further preferably, the complexing agent solution is ammonia water.

[0018] Preferably, the concentration of the complexing agent solution is 4-10 mol / L.

[0019] Preferably, the first antioxidant solution is any one or more of ascorbic acid (vitamin C), sodium citrate, citric acid; further preferably, the selected first antioxidant is ascorbic acid (vitamin C).

[0020] Preferably, the concentration of the first antioxidant solution is 0.15-0.5 g / L.

[0021] Preferably, the reaction kettle bottom liquid is prepared from water, a second oxidizing agent, a precipitating agent, and a complexing agent.

[0022] Preferably, the temperature of the reaction kettle bottom liquid is 40-60°C, the pH value is 11-12, and the alkalinity C(NH4 + ) is 3.0-9.0 g / L.

[0023] Preferably, the second antioxidant solution is any one or more of hydrazine hydrate solution, hydrazine solution, and carbohydrazide solution; further preferably, the selected second antioxidant is hydrazine hydrate solution.

[0024] Preferably, the concentration of the second antioxidant solution in the reaction kettle bottom liquid is 0.3-0.8 g / L.

[0025] Preferably, in steps 2 and 3, the alkalinity in the reaction system is 5-8 g / L.

[0026] Preferably, in steps 2 and 3, the temperature of the reaction system is 40-60°C; further preferably, the temperature of the reaction system is 50°C.

[0027] Preferably, in step 2, after 28-32 h of the first stage reaction or after the D50 of the precipitated particles is 2.0-2.5 μm, the second stage is entered; after 15-20 h of the second stage reaction or after the D50 of the precipitated particles is 3.0-3.5 μm, step 3 is entered.

[0028] Preferably, in step 3, the reaction time is 8-12 h or after the D50 of the precipitated particles is 3.7-5 μm, step 4 is entered.

[0029] Preferably, in step 2, the flow rate of the metal salt mixed solution A is 30%-90% of the flow rate of the metal salt mixed solution B in step 3.

[0030] Further preferably, in step 2, the flow rate of the metal salt mixed solution A is 80-360 mL / min; and in step 3, the flow rate of the metal salt mixed solution B is 180-420 mL / min.

[0031] Preferably, the inert gas for providing the inert atmosphere is any one or two or more of nitrogen, argon and neon.

[0032] Preferably, in step 3, the method further comprises: aging the slurry prepared in step 3 at room temperature for 0.5-1 h.

[0033] Preferably, in step 4, during drying, the washed precursor particles are first dried at 70-90℃ for 3-5 h, and then heated to 110-140℃ for 10-16 h.

[0034] In a third aspect, the present application provides a positive electrode material, wherein the raw material of the positive electrode material comprises the above-mentioned sodium-ion battery quaternary precursor or the sodium-ion battery quaternary precursor prepared by the above-mentioned preparation method.

[0035] In a fourth aspect, the present application provides a battery comprising the above-mentioned positive electrode material.

[0036] Compared with the prior art, the present application has the following obvious beneficial effects:

[0037] (1) The preparation method of the present application can prepare a quaternary sodium battery precursor containing ordered intercalation of flaky primary particles, uniform pore distribution and good sphericity of secondary particles. The precursor has a compact structure, high tap density and good product consistency. Moreover, the preparation method of the present application is simple, has strong applicability, requires relatively simple equipment, is easy to operate and has low control difficulty.

[0038] (2) The present application uses a two-stage method to prepare a "core-shell" structure precursor. The core with high tap density and good morphology is prepared, and then the doped metal is coated on the surface of the core by controlling the process conditions. By controlling the two-stage process parameters, the deposition rate of the doped metal is further controlled to prevent element segregation. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 SEM image of the precursor prepared in Example 1 of the present application;

[0040] Figure 2 SEM image of the precursor prepared in Example 4 of the present application;

[0041] Figure 3 SEM image of the precursor prepared in Comparative Example 1 of the present application;

[0042] Figure 4 SEM image of the precursor prepared in Comparative Example 2 of the present application;

[0043] Figure 5 SEM image of the precursor prepared for Inventive Comparative Example 3;

[0044] Figure 6 SEM image of the precursor prepared for Inventive Comparative Example 4;

[0045] Figure 7 SEM image of the precursor prepared for Inventive Comparative Example 5. DETAILED DESCRIPTION

[0046] The present application provides the following specific technical solutions.

[0047] In a first aspect, the present application provides a sodium-ion battery quaternary precursor, comprising a core and a shell layer coated on at least part of the surface of the core; the chemical formula of the core is Ni x1 Zn y1 Fe z1 Mn 1-x1-y1-z1 (OH)2, wherein 0.1≤x1≤0.4, 0≤y1≤0.03, 0.1≤z1≤0.5, x1+y1+z1<1; the chemical formula of the shell layer is Ni x2 Zn y2 Fe z2 Mn 1-x2-y21-z2 (OH)2, wherein 0.1≤x2≤0.4, 0.04≤y2≤0.12, 0.1≤z2≤0.5, x2+y2+z2<1; the tap density of the sodium-ion battery quaternary precursor is 1.4~1.8g / cm 3 .

[0048] Preferably, the primary particles of the sodium-ion battery quaternary precursor are orderly intercalated flaky; the secondary particles of the sodium-ion battery quaternary precursor are spherical or spheroidal.

[0049] In a second aspect, the present application provides a preparation method of a sodium-ion battery quaternary precursor, comprising the following steps:

[0050] Step 1, mixing nickel salt, iron salt, manganese salt, zinc salt and first antioxidant solution to obtain metal salt mixed solution A; mixing nickel salt, iron salt, manganese salt, zinc salt and first antioxidant solution to obtain metal salt mixed solution B; wherein the concentration of zinc salt in metal salt mixed solution B is higher than that in solution A;

[0051] Step 2, continuously feeding the metal salt mixed solution A, the precipitant solution and the complexing agent solution into the bottom liquid of the reaction kettle under an inert atmosphere to prepare the core, wherein the preparation of the core comprises a first stage and a second stage, the pH value in the reaction system in the first stage is higher than that in the second stage by 0.5-1.0; in the first stage, the pH value of the reaction system is adjusted to 11.0-12.0, and after a certain period of reaction, the second stage is entered, and then the pH value of the reaction system is adjusted to 10.5-11.0, and a certain period of reaction is carried out;

[0052] Step 3, stopping feeding the metal salt mixed solution A, continuously feeding the metal salt mixed solution B, the precipitant solution and the complexing agent solution into the bottom liquid of the reaction kettle, adjusting the pH value of the reaction system to 9-10, and reacting for a certain period of time to obtain a slurry;

[0053] Step 4, solid-liquid separation of the slurry prepared in step 3, followed by solid-liquid separation, washing and drying to obtain the sodium ion battery quaternary precursor material.

[0054] It should be noted that in the metal salt mixed solution A, the molar ratio of nickel, zinc, iron and manganese elements is consistent with the stoichiometric ratio of each element in the precursor core; in the metal salt mixed solution B, the molar ratio of nickel, zinc, iron and manganese elements is consistent with the stoichiometric ratio of each element in the precursor shell. In actual application, different element ratios of the precursor can be prepared by adjusting the ratio of salt A and salt B, for example: the core can be Ni 0.1 Zn 0.03 Fe 0.3 Mn 0.57 (OH)2, Ni 0.2 Zn 0.02 Fe 0.1 Mn 0.68 (OH)2, Ni 0.3 Zn 0.03 Fe 0.4 Mn 0.27 (OH)2, Ni 0.4 Zn 0.02 Fe 0.4 Mn 0.18 (OH)2, Ni 0.4 Fe 0.5 Mn 0.1 (OH)2; the shell can be Ni 0.1 Zn 0.1 Fe 0.5 Mn 0.3 (OH)2, Ni 0.2 Zn 0.04 Fe 0.4 Mn 0.36 (OH)2, Ni 0.3 Zn0.08 Fe 0.3 Mn 0.32 (OH)2, Ni 0.4 Zn 0.12 Fe 0.1 Mn 0.38 (OH)2; and in specific embodiments of the present application, in order to reduce the influence of the doping amount of zinc element on the morphology and tap density, the content of zinc element in the precursor samples prepared in the control examples and the comparative examples is consistent.

[0055] The inventors have found that when doping zinc element by the coprecipitation process, if the content of zinc element is high, zinc hydroxide is likely to be precipitated alone, resulting in a lower tap density of the secondary particles of the prepared precursor, thinner primary particles, and poorer sphericity. To solve the above problems, a higher pH value in step 2 (nucleation stage) is conducive to the nucleation of metal elements, and a lower pH value in step 3 (coating stage) is conducive to the rapid precipitation and growth of metal elements. Segmenting the pH value in the nucleation stage in step 2 is conducive to the coprecipitation of zinc element and other elements, and reduces the possibility of zinc element being precipitated alone.

[0056] Further preferred is that a small amount of zinc element is doped in the core, which can reduce the content of zinc element in the shell, make the precipitation of zinc element in the shell more uniform, reduce the possibility of segregation when doping zinc element, and improve the tap density of the precursor and optimize the morphology characteristics.

[0057] Preferably, each of the nickel salt, the iron salt, the manganese salt, and the zinc salt is independently any one or two or more of a sulfate, a nitrate, an acetate, and a chlorate.

[0058] Preferably, the precipitant solution is any one or two or more of a sodium hydroxide solution and a potassium hydroxide solution; further preferably, the precipitant solution is a sodium hydroxide solution.

[0059] Preferably, the concentration of the precipitant solution is 8-12 mol / L.

[0060] Preferably, the complexing agent solution is any one or two or more of a sodium citrate solution, a sodium fluoride solution, a hydroxyethyl ethylenediamine triacetate solution, a sodium gluconate solution, an ethylenediamine tetraacetate solution, a sodium ethylenediamine tetraacetate solution, and ammonia; further preferably, the complexing agent solution is ammonia.

[0061] Preferably, the concentration of the complexing agent solution is 4-10 mol / L.

[0062] Preferably, the first antioxidant solution is any one or two or more of ascorbic acid (vitamin C), sodium citrate, and citric acid; further preferably, the selected first antioxidant is ascorbic acid (vitamin C).

[0063] Preferably, the concentration of the first antioxidant solution is 0.15-0.5 g / L.

[0064] Preferably, the reaction kettle bottom solution is prepared from water, a second oxidizing agent, a precipitating agent and a complexing agent.

[0065] By adding the first antioxidant and the second antioxidant, the oxidation of ferrous ions and divalent manganese ions in the metal salt solution can be avoided, thereby avoiding the oxidation of ferrous ions and divalent manganese ions leading to segregation of the precipitation, making the particle growth trend worse, the morphology changing, and affecting the overall precipitation effect. The second antioxidant exhibits strong reducing property under alkaline conditions, which can effectively prevent the oxidation of ferrous ions and divalent manganese ions, further ensuring the stability in the initial stage of the reaction.

[0066] Preferably, the temperature of the reaction kettle bottom solution is 40-60℃, the pH value is 11-12, and the alkalinity C(NH4 + ) is 3.0-9.0 g / L.

[0067] By setting the reaction kettle bottom solution, the front and back fluctuations of the reaction conditions are controlled, and the influence of the reaction condition fluctuations on the reaction is reduced. If the bottom solution condition deviates too much from the reaction condition, it may lead to particle agglomeration or incomplete precipitation in the initial stage of the reaction, etc.

[0068] Preferably, the second antioxidant solution is any one or two or more of a hydrazine hydrate solution, a hydrazine solution and a carbohydrazide solution; further preferably, the selected second antioxidant is a hydrazine hydrate solution.

[0069] Preferably, the concentration of the second antioxidant solution in the reaction kettle bottom solution is 0.3-0.8 g / L.

[0070] Preferably, in steps 2 and 3, the alkalinity in the reaction system is 5-8 g / L.

[0071] Preferably, in steps 2 and 3, the temperature of the reaction system is 40-60℃.

[0072] In actual application, the temperature of the reaction system can be 40℃, 45℃, 50℃, 55℃ or 60℃.

[0073] Preferably, in step 2, after the first stage reaction for 28-32 h or the D50 of the precipitated particles is 2.0-2.5 μm, the second stage is entered; after the second stage reaction in step 2 for 15-20 h or the D50 of the precipitated particles is 3.0-3.5 μm, step 3 is entered.

[0074] Preferably, in step 3, the reaction time is 8-12 h or the D50 of the precipitated particles is 3.7-5 μm, and then step 4 is entered.

[0075] Preferably, in step 2, the flow rate of the metal salt mixed solution A is 30% to 90% of the flow rate of the metal salt mixed solution B in step 3.

[0076] The flow rate in step 3 is greater than that in step 2, and setting the flow rate in a gradient is conducive to accelerating the growth of the particle size.

[0077] Further preferably, in step 2, the flow rate of the metal salt mixed solution A is 80 to 360 mL / min; and in step 3, the flow rate of the metal salt mixed solution B is 180 to 420 mL / min.

[0078] Preferably, the inert gas for providing the inert atmosphere is any one or more of nitrogen, argon, and neon.

[0079] Preferably, in step 3, the method further comprises: aging the slurry prepared in step 3 at room temperature for 0.5 to 1 h.

[0080] Preferably, in step 4, during drying, the washed precursor particles are first dried at 70 to 90°C for 3 to 5 h, and then heated to 110 to 140°C for 10 to 16 h.

[0081] In a third aspect, the present application provides a positive electrode material, wherein the raw material of the positive electrode material comprises the sodium-ion battery quaternary precursor or the sodium-ion battery quaternary precursor prepared by the preparation method.

[0082] In a fourth aspect, the present application provides a battery comprising the positive electrode material.

[0083] To make the technical problems, technical solutions, and technical advantages of the present application clearer, specific examples will be described in detail below, but the protection scope of the present application is not limited to the following specific examples.

[0084] Unless otherwise defined, all the professional terms used below have the same meaning as generally understood by those skilled in the art. The professional terms used in the present application are only for the purpose of describing specific examples, and are not intended to limit the protection scope of the present application.

[0085] Unless otherwise specified, the various raw materials, reagents, instruments, and equipment used in the present application can be purchased on the market or can be prepared by existing methods.

[0086] Example 1:

[0087] A preparation method of a sodium-ion battery quaternary precursor comprises the following steps:

[0088] Step 1, mixed nickel sulfate solution, ferrous sulfate solution and manganese sulfate solution to prepare metal salt mixed solution A, the molar ratio of nickel, iron and manganese in the metal salt mixed solution A is 1:1:1, and the total concentration of metal ions is 2 mol / L. Mixed nickel sulfate solution, zinc sulfate solution, ferrous sulfate solution and manganese sulfate solution to prepare metal salt mixed solution B, the molar ratio of nickel, iron, manganese and zinc in the metal salt mixed solution B is 0.24:0.33:0.33:0.10, and the total concentration of metal ions is 2 mol / L. Ascorbic acid is added to the two metal salt solutions, and the concentration of ascorbic acid in the metal salt mixed solution A and the metal salt mixed solution B is 0.3 g / L. Prepare 6.7 mol / L ammonia water and 10.8 mol / L sodium hydroxide solution.

[0089] Step 2, reaction bottom solution preparation: 200 L of pure water is introduced into a 300 L reaction kettle, and the temperature is raised to 50℃. 300 mL of hydrazine hydrate with a mass concentration of 25%, 120 mL of NaOH solution and 3000 mL of ammonia water solution are added to the reaction kettle, the alkalinity of the reaction kettle bottom solution is adjusted to 7.0 g / L, and the pH value is 11.40. Then N2 is introduced into the reaction kettle, the flow rate is 20 L / h, and the replacement time is 1 h.

[0090] Step 3, continuously introduce metal salt mixed solution A, ammonia water and sodium hydroxide solution into the reaction kettle bottom solution, the flow rate of metal salt mixed solution A is 120 mL / min, the flow rate of ammonia water is 20 mL / min, and the flow rate of sodium hydroxide is 50 mL / min. The pH value of the reaction system is controlled at 11.0-11.5, and the alkalinity is controlled at 7 g / L; the stirring rate in the reaction kettle is 500 r / min, the pH value of the reaction system is controlled at 10.5-11.0 after 30 h of reaction, and the introduction of metal salt mixed solution A is stopped after 20 h of continuous reaction; the core of the precursor is obtained, and the general formula is Ni 0.33 Fe 0.33 Mn 0.33 (OH)2.

[0091] Step 4, introduce metal salt mixed solution B into the reaction system, the flow rate of metal salt mixed solution B is 360 mL / min, the flow rate of ammonia water is adjusted to 60 mL / min, the flow rate of sodium hydroxide solution is 150 mL / min, the pH value of the reaction system is controlled at 9.5-10.0, and the alkalinity is controlled at 7.0 g / L. Stop introducing metal salt mixed solution B, ammonia water and sodium hydroxide solution after 11 h of reaction.

[0092] Step 5, aging, 150L of 5% sodium hydroxide solution was added to the reactor and aged for 0.5h, then the aged slurry was filtered, the obtained solid particles were washed repeatedly with pure water, and the washing was stopped when the pH value of the deionized water after washing was less than 8.0; then the solid particles were dried at a temperature of 80℃ for 4h and then the temperature was increased to 120℃ for drying for 14h, to obtain the precursor, the general formula is Ni 0.33 Fe 0.33 Mn 0.33 (OH)2@Ni 0.24 Zn 0.1 Fe 0.33 Mn 0.33 (OH)2.

[0093] Example 2:

[0094] A preparation method of a sodium ion battery quaternary precursor, comprising the following steps:

[0095] Step 1, mixed nickel sulfate solution, ferrous sulfate solution, manganese sulfate solution and zinc nitrate solution to prepare metal salt mixed solution A, the molar ratio of nickel, iron, manganese and zinc in the metal salt mixed solution A is 0.33:0.33:0.33:0.01, and the total concentration of metal ions is 2mol / L. Mixed nickel sulfate solution, zinc sulfate solution, ferrous sulfate solution and manganese sulfate solution to prepare metal salt mixed solution B, the molar ratio of nickel, iron, manganese and zinc in the metal salt mixed solution B is 0.24:0.33:0.33:0.10, and the total concentration of metal ions is 2mol / L. Ascorbic acid is added to the two kinds of metal salt solutions, and the concentration of sodium citrate in the metal salt mixed solution A and the metal salt mixed solution B is 0.15g / L. Prepare 6.7mol / L of ammonia water and 10.8mol / L of sodium hydroxide solution.

[0096] Step 2, reaction bottom solution preparation: 200L of pure water was introduced into a 300L reactor, and the temperature was increased to 50℃, 300mL of 25% hydrazine hydrate, 120mL of NaOH solution and 2000mL of ammonia water solution were added to the reactor, the alkalinity of the bottom solution of the reactor was adjusted to 5g / L, and the pH value was 11.10. Then N2 was introduced into the reactor, the flow rate was 20L / h, and the air in the reactor was replaced for 1h.

[0097] Step 3, continuously feeding the metal salt mixed solution A, ammonia water and sodium hydroxide solution into the bottom liquid of the reaction kettle, the flow rate of the metal salt mixed solution A is 80 mL / min, the flow rate of the ammonia water is 10 mL / min, and the flow rate of the sodium hydroxide solution is 30 mL / min, the pH value of the reaction system is controlled to be 11.0-11.5, the alkalinity is controlled to be 5 g / L, the stirring speed in the reaction kettle is 500 r / min, after 30 h of reaction, the pH value of the reaction system is controlled to be 10.5-11.0, and after 20 h of continuous reaction, the feeding of the metal salt mixed solution A is stopped; the core of the precursor is obtained, and the general formula is Ni 0.33 Zn 0.01 Fe 0.33 Mn 0.33 (OH)2.

[0098] Step 4, feeding the metal salt mixed solution B into the reaction system, the flow rate of the metal salt mixed solution B is 180 mL / min, the flow rate of the ammonia water is adjusted to be 30 mL / min, the flow rate of the sodium hydroxide solution is 75 mL / min, the pH value of the reaction system is controlled to be 9.0-9.5, the alkalinity is controlled to be 5 g / L, and after 11 h of reaction, the feeding of the metal salt mixed solution B, the ammonia water and the sodium hydroxide solution is stopped.

[0099] Step 5, aging, adding 150 L of 5% sodium hydroxide solution into the reaction kettle for aging for 0.5 h, then filtering the aged slurry, repeatedly washing the obtained solid particles with pure water, and stopping the washing when the pH value of the deionized water after washing is less than 8.0; then drying the solid particles at a temperature of 80 ℃ for 4 h and then increasing the temperature to 120 ℃ for drying for 14 h, to obtain the precursor, and the general formula is Ni 0.33 Zn 0.01 Fe 0.33 Mn 0.33 (OH)2@Ni 0.24 Zn 0.1 Fe 0.33 Mn 0.33 (OH)2.

[0100] Example 3:

[0101] A preparation method of a sodium ion battery quaternary precursor includes the following steps:

[0102] Step 1, mixed nickel sulfate solution, ferrous sulfate solution, manganese sulfate solution and zinc sulfate solution to prepare metal salt mixed solution A, the molar ratio of nickel, iron, manganese, zinc in metal salt mixed solution A is 0.31:0.33:0.33:0.03, the total concentration of metal ions is 2 mol / L. Mixed sulfuric acid solution, zinc sulfate solution, ferrous sulfate solution and manganese sulfate solution to prepare metal salt mixed solution B, the molar ratio of nickel, iron, manganese, zinc in metal salt mixed solution B is 0.26:0.33:0.33:0.08, the total concentration of metal ions is 2 mol / L. Add ascorbic acid in the two kinds of metal salt solution, the concentration of sodium citrate in metal salt mixed solution A and metal salt mixed solution B is 0.5 g / L. Prepare 6.7 mol / L ammonia water and 10.8 mol / L sodium hydroxide solution.

[0103] Step 2, reaction bottom solution preparation: 200 L of pure water is introduced into a 300 L reaction kettle, and the temperature is raised to 50℃, 300 mL of 25% hydrazine hydrate, 150 mL of NaOH solution and 3500 mL of ammonia water solution are added into the reaction kettle, the alkalinity of the reaction kettle bottom solution is adjusted to 8 g / L, and the pH value is 11.60. Then N2 is introduced into the reaction kettle, the flow rate is 20 L / h, and the replacement time of the air in the reaction kettle is 1 h.

[0104] Step 3, continuously introduce metal salt mixed solution A, ammonia water and sodium hydroxide solution into the reaction kettle bottom solution, the flow rate of metal salt mixed solution A is 360 mL / min, the flow rate of ammonia water is 60 mL / min, and the flow rate of sodium hydroxide is 150 mL / min, the pH value of the reaction system is controlled at 11.5~12.0, the alkalinity is 8 g / L, the stirring rate in the reaction kettle is 500 r / min, after 30 h of reaction, the pH value of the reaction system is controlled at 10.5~11.0, and after 20 h of continuous reaction, the metal salt mixed solution A is stopped, and the core of the precursor is obtained, the general formula is Ni 0.31 Zn 0.03 Fe 0.33 Mn 0.33 (OH)2.

[0105] Step 4, introduce metal salt mixed solution B into the reaction system, the flow rate of metal salt mixed solution B is 420 mL / min, the flow rate of ammonia water is adjusted to 80 mL / min, the flow rate of sodium hydroxide solution is 180 mL / min, the pH value of the reaction system is controlled at 9.5~10.0, the alkalinity is 8 g / L, and after 11 h of reaction, the metal salt mixed solution B, ammonia water and sodium hydroxide solution are stopped.

[0106] Step 5, aging, 150L of 5% sodium hydroxide solution was added to the reactor and aged for 0.5h, then the aged slurry was filtered, the obtained solid particles were washed repeatedly with pure water, and the washing was stopped when the pH value of the deionized water after washing was less than 8.0; then the solid particles were dried at 80℃ for 4h and then heated to 120℃ for 14h, to obtain the precursor, the general formula is Ni 0.31 Zn 0.03 Fe 0.33 Mn 0.33 (OH)2@Ni 0.26 Zn 0.08 Fe 0.33 Mn 0.33 (OH)2.

[0107] Example 4:

[0108] A preparation method of a sodium ion battery quaternary precursor, comprising the following steps:

[0109] Step 1, mixed nickel sulfate solution, ferrous sulfate solution, manganese sulfate solution and zinc sulfate solution to prepare metal salt mixed solution A, the molar ratio of nickel, iron, manganese and zinc in the metal salt mixed solution A is 0.33:0.33:0.33:0.01, and the total concentration of metal ions is 2mol / L. Mixed nickel sulfate solution, zinc sulfate solution, ferrous sulfate solution and manganese sulfate solution to prepare metal salt mixed solution B, the molar ratio of nickel, iron, manganese and zinc in the metal salt mixed solution B is 0.24:0.33:0.33:0.10, and the total concentration of metal ions is 2mol / L. Ascorbic acid is added to the two kinds of metal salt solutions, and the concentration of ascorbic acid in the metal salt mixed solution A and the metal salt mixed solution B is 0.3g / L. 6.7mol / L of ammonia water and 10.8mol / L of sodium hydroxide solution

[0110] Step 2, reaction bottom solution preparation: 200L of pure water was introduced into a 300L reactor, and the temperature was raised to 50℃, 300mL of 25% hydrazine hydrate, 120mL of NaOH solution and 3000mL of ammonia water solution were added to the reactor, the alkalinity of the bottom solution of the reactor was adjusted to 7.0g / L, and the pH value was 11.40. Then N2 was introduced into the reactor, the flow rate was 20L / h, and the air in the reactor was replaced for 1h.

[0111] Step 3, continuously feeding the metal salt mixed solution A, ammonia water and sodium hydroxide solution into the bottom liquid of the reaction kettle, the flow rate of the metal salt mixed solution A is 120 mL / min, the flow rate of the ammonia water is 20 mL / min, and the flow rate of the sodium hydroxide solution is 50 mL / min, the pH value of the reaction system is controlled to be 11.0-11.5, and the alkalinity is controlled to be 7 g / L; the stirring speed in the reaction kettle is 500 r / min, the pH value of the reaction system is controlled to be 10.5-11.0 after 30 h of reaction, and the metal salt mixed solution A is continuously fed after 20 h of reaction, to obtain the core of the precursor, and the general formula is Ni 0.33 Zn 0.01 Fe 0.33 Mn 0.33 (OH)2.

[0112] Step 4, feeding the metal salt mixed solution B into the reaction system, the flow rate of the metal salt mixed solution B is 270 mL / min, the flow rate of the ammonia water is adjusted to be 45 mL / min, the flow rate of the sodium hydroxide solution is 120 mL / min, the pH value of the reaction system is controlled to be 9.5-10.0, and the alkalinity is controlled to be 7 g / L, and the feeding of the metal salt mixed solution B, ammonia water and sodium hydroxide solution is stopped after 11 h of reaction.

[0113] Step 5, aging, adding 150 L of 5% sodium hydroxide solution into the reaction kettle for aging for 0.5 h, then filtering the aged slurry, repeatedly washing the obtained solid particles with pure water, and stopping the washing when the pH value of the deionized water after washing is less than 8.0; then drying the solid particles at a temperature of 80°C for 4 h and then increasing the temperature to 120°C for drying for 14 h, to obtain the precursor, and the general formula is Ni 0.33 Zn 0.01 Fe 0.33 Mn 0.33 (OH)2@Ni 0.24 Zn 0.1 Fe 0.33 Mn 0.33 (OH)2.

[0114] Example 5:

[0115] A preparation method of a sodium ion battery quaternary precursor includes the following steps:

[0116] Step 1, mixed nickel sulfate solution, ferrous sulfate solution, manganese sulfate solution and zinc sulfate solution to prepare metal salt mixed solution A, the molar ratio of nickel, iron, manganese, zinc in metal salt mixed solution A is 0.32:0.33:0.33:0.02, the total concentration of metal ions is 2 mol / L. Mixed nickel sulfate solution, zinc sulfate solution, ferrous sulfate solution and manganese sulfate solution to prepare metal salt mixed solution B, the molar ratio of nickel, iron, manganese, zinc in metal salt mixed solution B is 0.26:0.33:0.33:0.08, the total concentration of metal ions is 2 mol / L. Ascorbic acid is added to the two metal salt solutions, the concentration of ascorbic acid in metal salt mixed solution A and metal salt mixed solution B is 0.3 g / L. Prepare 6.7 mol / L ammonia water and 10.8 mol / L sodium hydroxide solution

[0117] Step 2, reaction bottom solution preparation: 200 L of pure water is introduced into a 300 L reaction kettle, and the temperature is raised to 50℃, 300 mL of 25% mass concentration of hydrazine hydrate, 120 mL of NaOH solution and 3000 mL of ammonia water solution are added to the reaction kettle, the alkalinity of the reaction kettle bottom solution is adjusted to 7.0 g / L, and the pH value is 11.40. Then N2 is introduced into the reaction kettle, the flow rate is 20 L / h, and the replacement time of the air in the reaction kettle is 1 h.

[0118] Step 3, continuously introduce metal salt mixed solution A, ammonia water and sodium hydroxide solution into the reaction kettle bottom solution, the flow rate of metal salt mixed solution A is 120 mL / min, the flow rate of ammonia water is 20 mL / min, and the flow rate of sodium hydroxide is 50 mL / min, the pH value of the reaction system is controlled at 11.0-11.5, and the alkalinity is controlled at 7 g / L; the stirring rate in the reaction kettle is 500 r / min, after 30 h of reaction, the pH value of the reaction system is controlled at 10.5-11.0, and after 20 h of continuous reaction, the introduction of metal salt mixed solution A is stopped, and the core of the precursor is obtained, the general formula is Ni 0.32 Zn 0.02 Fe 0.33 Mn 0.33 (OH)2.

[0119] Step 4, introduce metal salt mixed solution B into the reaction system, the flow rate of metal salt mixed solution B is 270 mL / min, the flow rate of ammonia water is adjusted to 45 mL / min, the flow rate of sodium hydroxide solution is 120 mL / min, the pH value of the reaction system is controlled at 9.5-10.0, and the alkalinity is controlled at 7 g / L, after 11 h of reaction, stop introducing metal salt mixed solution B, ammonia water and sodium hydroxide solution.

[0120] Step 5, aging, 150L of 5% sodium hydroxide solution was added into the reactor and aged for 0.5h, then the aged slurry was filtered, the obtained solid particles were washed repeatedly with pure water, the pH value of the deionized water after washing was less than 8.0, then the solid particles were dried at 80℃ for 4h and then at 120℃ for 14h, to obtain the precursor, the general formula is Ni 0.32 Zn 0.02 Fe 0.33 Mn 0.33 (OH)2@Ni 0.26 Zn 0.08 Fe 0.33 Mn 0.33 (OH)2.

[0121] Comparative Example 1:

[0122] A preparation method of a sodium ion battery quaternary precursor, comprising the following steps:

[0123] Step 1, mixed nickel sulfate solution, ferrous sulfate solution and manganese sulfate solution to prepare metal salt mixed solution A, the molar ratio of nickel, iron and manganese in the metal salt mixed solution A is 1:1:1, and the total concentration of metal ions is 2mol / L. Mixed nickel sulfate solution, zinc sulfate solution, ferrous sulfate solution and manganese sulfate solution to prepare metal salt mixed solution B, the molar ratio of nickel, iron, manganese and zinc in the metal salt mixed solution B is 0.24:0.33:0.33:0.10, and the total concentration of metal ions is 2mol / L. Ascorbic acid is added to the two kinds of metal salt solutions, and the concentration of ascorbic acid in the metal salt mixed solution A and the metal salt mixed solution B is 0.3g / L. 6.7mol / L of ammonia water and 10.8mol / L of sodium hydroxide solution are prepared.

[0124] Step 2, reaction bottom solution preparation: 200L of pure water was introduced into a 300L reactor, and the temperature was raised to 50℃, 300mL of 25% hydrazine hydrate, 120mL of NaOH solution and 3000mL of ammonia water solution were added into the reactor, the alkalinity of the bottom solution of the reactor was adjusted to 7.0g / L, and the pH value was 11.40. Then N2 was introduced into the reactor at a flow rate of 20L / h, and the air in the reactor was replaced for 1h.

[0125] Step 3, continuously feeding the metal salt mixed solution A, ammonia water and sodium hydroxide solution into the bottom liquid of the reaction kettle, the flow rate of the metal salt mixed solution A is 120 mL / min, the flow rate of the ammonia water is 20 mL / min, and the flow rate of the sodium hydroxide solution is 50 mL / min, the pH value of the reaction system is controlled to be 11.0-11.5, and the alkalinity is 7 g / L; the stirring speed in the reaction kettle is 500 r / min, and after 50 h of reaction, the feeding of the metal salt mixed solution A is stopped, and the core of the precursor is obtained, and the general formula is Ni 0.33 Fe 0.33 Mn 0.33 (OH)2.

[0126] Step 4, feeding the metal salt mixed solution B into the reaction system, the flow rate of the metal salt mixed solution B is 360 mL / min, the flow rate of the ammonia water is adjusted to 60 mL / min, the flow rate of the sodium hydroxide solution is 150 mL / min, the pH value of the reaction system is controlled to be 9.5-10.0, and the alkalinity is 7.0 g / L, and after 11 h of reaction, the feeding of the metal salt mixed solution B, ammonia water and sodium hydroxide solution is stopped.

[0127] Step 5, aging, adding 150 L of 5% sodium hydroxide solution into the reaction kettle for aging for 0.5 h, then filtering the aged slurry, and repeatedly washing the obtained solid particles with pure water, and stopping the washing when the pH value of the deionized water after washing is less than 8.0; then drying the solid particles at a temperature of 80°C for 4 h and then increasing the temperature to 120°C for drying for 14 h, to obtain the precursor, and the general formula is Ni 0.33 Fe 0.33 Mn 0.33 (OH)2@Ni 0.24 Zn 0.1 Fe 0.33 Mn 0.33 (OH)2.

[0128] Comparative Example 2:

[0129] A preparation method of a sodium ion battery quaternary precursor includes the following steps:

[0130] Step 1, mixed nickel sulfate solution, ferrous sulfate solution, zinc sulfate solution and manganese sulfate solution to prepare metal salt mixed solution A, the molar ratio of nickel, iron, manganese, zinc in the metal salt mixed solution A is 0.33:0.33:0.33:0.01, the total concentration of metal ions is 2 mol / L. Mixed nickel sulfate solution, zinc sulfate solution, ferrous sulfate solution and manganese sulfate solution to prepare metal salt mixed solution B, the molar ratio of nickel, iron, manganese, zinc in the metal salt mixed solution B is 0.24:0.33:0.33:0.10, the total concentration of metal ions is 2 mol / L. Ascorbic acid is added in the two kinds of metal salt solutions, the concentration of ascorbic acid in the metal salt mixed solution A and the metal salt mixed solution B is 0.3 g / L. Prepare 6.7 mol / L ammonia water and 10.8 mol / L sodium hydroxide solution.

[0131] Step 2, reaction bottom solution preparation: 200 L of pure water is introduced into a 300 L reaction kettle, and the temperature is raised to 50℃. 300 mL of hydrazine hydrate with a mass concentration of 25%, 120 mL of NaOH solution and 3000 mL of ammonia water solution are added into the reaction kettle, the alkalinity of the reaction kettle bottom solution is adjusted to 7.0 g / L, and the pH value is 11.40. Then N2 is introduced into the reaction kettle, the flow rate is 20 L / h, and the continuous introduction time is 1 h, replacing the air in the reaction kettle.

[0132] Step 3, continuously introduce the metal salt mixed solution A, ammonia water and sodium hydroxide solution into the reaction kettle bottom solution, the flow rate of the metal salt mixed solution A is 120 mL / min, the flow rate of the ammonia water is 20 mL / min, and the flow rate of the sodium hydroxide is 50 mL / min, the pH value of the reaction system is controlled at 11.0-11.5, and the alkalinity is controlled at 7 g / L; the stirring rate in the reaction kettle is 500 r / min, after 30 h of reaction, the pH value of the reaction system is controlled at 10.5-11.0, and after 20 h of continuous reaction, the introduction of the metal salt mixed solution A is stopped, and the core of the precursor is obtained, the general formula is Ni 0.33 Zn 0.01 Fe 0.33 Mn 0.33 (OH)2.

[0133] Step 4, introduce the metal salt mixed solution B into the reaction system, the flow rate of the metal salt mixed solution B is 270 mL / min, the flow rate of the ammonia water is adjusted to 45 mL / min, and the flow rate of the sodium hydroxide solution is 120 mL / min, the pH value of the reaction system is maintained at 10.5-11.0, and the alkalinity is maintained at 7 g / L. After 11 h of reaction, when the D50 of the precipitated particles is 3.7-5 μm, the introduction of the metal salt mixed solution B, ammonia water and sodium hydroxide solution is stopped.

[0134] Step 5, aging, 150L of 5% sodium hydroxide solution was added to the reactor and aged for 0.5h, then the aged slurry was filtered, the obtained solid particles were washed repeatedly with pure water, and the washing was stopped when the pH value of the deionized water after washing was less than 8.0; then the solid particles were dried at 80℃ for 4h and then heated to 120℃ for 14h, to obtain the precursor, the general formula is Ni 0.33 Zn 0.01 Fe 0.33 Mn 0.33 (OH)2@Ni 0.24 Zn 0.1 Fe 0.33 Mn 0.33 (OH)2.

[0135] Comparative Example 3:

[0136] A preparation method of a sodium ion battery quaternary precursor, comprising the following steps:

[0137] Step 1, mixed nickel sulfate solution, zinc sulfate solution, ferrous sulfate solution and manganese sulfate solution to prepare metal salt mixed solution B, the molar ratio of nickel, iron, manganese and zinc in the metal salt mixed solution B is 0.30:0.33:0.33:0.04, and the total concentration of metal ions is 2mol / L. Ascorbic acid is added to the two metal salt solutions, and the concentration of ascorbic acid in the metal salt mixed solution B is 0.3g / L. 6.7mol / L of ammonia water and 10.8mol / L of sodium hydroxide solution are prepared.

[0138] Step 2, reaction bottom solution preparation: 200L of pure water was introduced into a 300L reactor, and the temperature was raised to 50℃, 300mL of 25% hydrazine hydrate, 120mL of NaOH solution and 3000mL of ammonia water solution were added to the reactor, the alkalinity of the bottom solution of the reactor was adjusted to 7.0g / L, and the pH value was 11.40. Then N2 was introduced into the reactor at a flow rate of 20L / h, and the air in the reactor was replaced for 1h.

[0139] Step 3, continuously introduce the metal salt mixed solution B into the bottom solution of the reactor, the flow rate of the metal salt mixed solution B is 120mL / min, the flow rate of the ammonia water is adjusted to 20mL / min, the flow rate of the sodium hydroxide solution is 50mL / min, the pH value of the reaction system is controlled to be 10.5-11.5, and the alkalinity is 7g / L, and the reaction is stopped after 83h.

[0140] Step 4, aging, 150 L of 5% sodium hydroxide solution was added into the reactor and aged for 0.5 h, then the aged slurry was filtered, the obtained solid particles were repeatedly washed with pure water, and the washing was stopped when the pH value of the deionized water after washing was less than 8.0; then the solid particles were dried at 80 ℃ for 4 h and then at 120 ℃ for 14 h, to obtain the precursor Ni 0.30 Zn 0.04 Fe 0.33 Mn 0.33 (OH)2.

[0141] Comparative Example 4:

[0142] A preparation method of a quaternary precursor of a sodium ion battery, comprising the following steps:

[0143] Step 1, a metal salt mixed solution A was prepared by mixing a nickel sulfate solution, a ferrous sulfate solution, a manganese sulfate solution and a zinc sulfate solution, the molar ratio of nickel, iron, manganese and zinc in the metal salt mixed solution A was 0.30:0.32:0.32:0.06, and the total concentration of metal ions was 2 mol / L. A metal salt mixed solution B was prepared by mixing a nickel sulfate solution, a zinc sulfate solution, a ferrous sulfate solution and a manganese sulfate solution, the molar ratio of nickel, iron, manganese and zinc in the metal salt mixed solution B was 0.30:0.34:0.34:0.02, and the total concentration of metal ions was 2 mol / L. Ascorbic acid was added to the two metal salt solutions, and the concentration of ascorbic acid in the metal salt mixed solution A and the metal salt mixed solution B was 0.3 g / L. 6.7 mol / L of ammonia water and 10.8 mol / L of sodium hydroxide solution were prepared.

[0144] Step 2, reaction bottom solution preparation: 200 L of pure water was introduced into a 300 L reactor, and the temperature was raised to 50 ℃. 300 mL of 25% hydrazine hydrate, 120 mL of NaOH solution and 3000 mL of ammonia water solution were added into the reactor, the alkalinity of the bottom solution of the reactor was adjusted to 7.0 g / L, and the pH value was 11.40. Then N2 was introduced into the reactor at a flow rate of 20 L / h for 1 h to replace the air in the reactor.

[0145] Step 3, metal salt mixed solution A, ammonia water and sodium hydroxide solution were continuously introduced into the bottom solution of the reactor, the flow rate of the metal salt mixed solution A was 120 mL / min, the flow rate of the ammonia water was 20 mL / min, and the flow rate of the sodium hydroxide was 50 mL / min, the pH value of the reaction system was controlled to be 11.0-11.5, and the alkalinity was controlled to be 7 g / L; the stirring rate in the reactor was 500 r / min, after 30 h of reaction, the pH value of the reaction system was controlled to be 10.5-11.0, and after 20 h of continuous reaction, the introduction of the metal salt mixed solution A was stopped, to obtain the core of the precursor, the general formula of which was Ni 0.30 Zn0.06 Fe 0.32 Mn 0.32 (OH)2.

[0146] Step 4, introduce the metal salt mixed solution B into the reaction system, the flow rate of the metal salt mixed solution B is 360 mL / min, the flow rate of the ammonia water is 60 mL / min, the flow rate of the sodium hydroxide solution is 150 mL / min, the pH value of the reaction system is controlled at 9.5-10.0, the alkalinity is 7 g / L, and the introduction of the metal salt mixed solution B, the ammonia water and the sodium hydroxide solution is stopped after 17 h of reaction.

[0147] Step 5, aging, 150 L of 5% sodium hydroxide solution is added into the reaction kettle for aging for 0.5 h, then the aged slurry is filtered, the obtained solid particles are repeatedly washed with pure water, the pH value of the deionized water after washing is less than 8.0, and then the washing is stopped; then the solid particles are dried at 80℃ for 4 h and then heated to 120℃ for drying for 14 h, to obtain the precursor, the general formula is Ni 0.30 Zn 0.06 Fe 0.32 Mn 0.32 (OH)2@Ni 0.3 Zn 0.02 Fe 0.34 Mn 0.34 (OH)2.

[0148] Comparative Example 5:

[0149] A preparation method of a sodium ion battery quaternary precursor, comprising the following steps:

[0150] Step 1, a metal salt mixed solution A is prepared by mixing a nickel sulfate solution, a ferrous sulfate solution, a manganese sulfate solution and a zinc sulfate solution, the molar ratio of nickel, iron, manganese and zinc in the metal salt mixed solution A is 0.33:0.33:0.33:0.01, and the total concentration of metal ions is 2 mol / L. A metal salt mixed solution B is prepared by mixing a nickel sulfate solution, a zinc sulfate solution, a ferrous sulfate solution and a manganese sulfate solution, the molar ratio of nickel, iron, manganese and zinc in the metal salt mixed solution B is 0.24:0.33:0.33:0.10, and the total concentration of metal ions is 2 mol / L. 6.7 mol / L of ammonia water and 10.8 mol / L of sodium hydroxide solution are prepared.

[0151] Step 2, reaction bottom solution preparation: 200 L of pure water is introduced into a 300 L reaction kettle, and the temperature is raised to 50℃, 120 mL of NaOH solution and 3000 mL of ammonia water solution are added into the reaction kettle, the alkalinity of the reaction kettle bottom solution is adjusted to 7.0 g / L, and the pH value is 11.40. Then N2 is introduced into the reaction kettle at a flow rate of 20 L / h, and the air in the reaction kettle is replaced for 1 h.

[0152] Step 3, continuously feeding the mixed metal salt solution A, ammonia water and sodium hydroxide solution into the bottom liquid of the reactor, the flow rate of the mixed metal salt solution A is 120 mL / min, the flow rate of the ammonia water is 20 mL / min, and the flow rate of the sodium hydroxide is 50 mL / min, the pH value of the reaction system is controlled at 11.0-11.5, and the alkalinity is controlled at 7 g / L; the stirring rate in the reactor is 500 r / min, the pH value of the reaction system is controlled at 10.5-11.0 after 30 h of reaction, and the mixed metal salt solution A is continuously fed into the reactor after 20 h of continuous reaction, thereby obtaining the core of the precursor, and the general formula is Ni 0.33 Zn 0.01 Fe 0.33 Mn 0.33 (OH)2.

[0153] Step 4, feeding the mixed metal salt solution B into the reaction system, the flow rate of the mixed metal salt solution B is 270 mL / min, the flow rate of the ammonia water is adjusted to 45 mL / min, the flow rate of the sodium hydroxide solution is 120 mL / min, the pH value of the reaction system is controlled at 9.5-10.0, and the alkalinity is controlled at 7 g / L, and the feeding of the mixed metal salt solution B, ammonia water and sodium hydroxide solution is stopped after 11 h of reaction.

[0154] Step 5, aging, adding 150 L of 5% sodium hydroxide solution into the reactor for aging for 0.5 h, then filtering the aged slurry, and repeatedly washing the obtained solid particles with pure water, and stopping the washing when the pH value of the deionized water after washing is less than 8.0; then drying the solid particles at a temperature of 80°C for 4 h and then increasing the temperature to 120°C for drying for 14 h, thereby obtaining the precursor, and the general formula is Ni 0.33 Zn 0.01 Fe 0.33 Mn 0.33 (OH)2@Ni 0.24 Zn 0.1 Fe 0.33 Mn 0.33 (OH)2.

[0155] The precursors prepared in Examples 1-5 and Comparative Examples 1-5 are sampled and tested, the element content of the precursors is tested by ICP, the tap density of the precursors is tested by a tap density instrument, and the D50 of the precursors is tested by a laser particle size instrument, and the test results are shown in Table 1.

[0156] Table 1 Element content, D50 and tap density of the sodium ion battery quaternary precursors prepared in Examples 1-5 and Comparative Examples 1-5

[0157]

[0158] The tap density of the precursors prepared in Comparative Example 1 and Example 4 is compared, and the tap density of the precursor prepared in Example 4 is higher. The inventor speculates that the core doped with a small amount of zinc element can reduce the content of zinc element in the shell layer, make the precipitation of zinc element in the shell layer more uniform, reduce the possibility of separate precipitation, and improve the tap density.

[0159] The tap density of the precursors prepared in Comparative Example 1 and Comparative Example 1 is compared, and it can be seen that the density of the precursor prepared in Example 1 is high, which can prove that the step-by-step adjustment of pH value during the precipitation of the core is beneficial to the co-precipitation of zinc element and other elements, and avoids the separate precipitation of zinc, thereby improving the tap density of the precursor.

[0160] Comparative Example 4 and Example 2 are compared, and the tap density of the precursor prepared in Example 4 is higher. The inventor speculates that the pH value of the first-stage precipitation is higher than that of the second-stage precipitation, which is beneficial to the complete precipitation of zinc hydroxide, makes the structure more compact, and is beneficial to the improvement of the tap density.

[0161] The tap density of the precursors prepared in Comparative Example 4 and Comparative Example 3 is compared, and it can be seen that the tap density of the precursor prepared in Example 4 is higher. The zinc element and other metal elements are difficult to co-precipitate, and direct co-precipitation can easily lead to the separate precipitation of zinc hydroxide, thereby affecting the tap density of the precursor.

[0162] The tap density of the precursors prepared in Comparative Example 4 and Comparative Example 4 is compared, and the tap density of the precursor prepared in Example 4 is higher. The inventor speculates that the zinc content concentration in the core is lower than that in the coating layer, which can improve the tap density. If the zinc content in the core is too high, zinc hydroxide is easy to separate, the structure of the core is loose, and the tap density is reduced.

[0163] Comparative Example 4 and Comparative Example 5 are compared, and the addition of an antioxidant can cause the sample to be oxidized to a certain extent during preparation, the primary particles become thin, and the tap density decreases.

[0164] Figure 1 The SEM image of the precursor prepared in Example 1 of the present application is shown in FIG. 1. Figure 1 It can be seen that the primary particles of the precursor are uniform intercalated thick sheets, the secondary particles have good sphericity, the particles are relatively dense, and there is no agglomeration phenomenon.

[0165] Figure 2 The SEM image of the precursor prepared in Example 4 of the present application is shown in FIG. 4. Figure 2 It can be seen that the primary particles of the precursor are uniform intercalated thick sheets, the secondary particles have good sphericity, the particles are relatively dense, and there is no agglomeration phenomenon.

[0166] Comparing Figure 1 and Figure 2It can be seen that the primary particles of the precursor prepared in Example 4 are more compact and have better sphericity, which indicates that doping a small amount of zinc in the core is more conducive to improving the co-deposition of zinc and other elements in the precursor. In combination with the data in Table 1, it can be further proved that doping zinc in the core is beneficial to improving the morphology and tap density of the precursor.

[0167] Figure 3 The SEM image of the precursor prepared in Comparative Example 1 is shown in FIG. 1. Figure 3 It can be seen that the primary particles of the precursor are uniform intercalated thick sheets, and there are flocculent structures on the surface of the primary particles. The secondary particles are spherical and have no agglomeration phenomenon.

[0168] Comparing Figure 3 and Figure 1 , Figure 2 respectively, it can be seen that the sphericity of the precursor prepared in Comparative Example 1 is relatively loose in the naked eye observation of the surface structure of the precursor, which further proves that doping a small amount of zinc in the core is beneficial to improving the morphology and tap density of the precursor.

[0169] Figure 4 The SEM image of the precursor prepared in Comparative Example 2 is shown in FIG. 2. Figure 4 It can be seen that the primary particles of the precursor prepared in Comparative Example 2 are intercalated thick sheets, and the sphericity of the secondary particles is poor.

[0170] The inventors speculate that the reason for the poor morphology and tap density of the precursor in Comparative Example 2 is that the pH value in the "core-shell" stage is not adjusted, which affects the morphology and tap density of the precursor.

[0171] Figure 5 The SEM image of the precursor prepared in Comparative Example 3 is shown in FIG. 3. Figure 5 It can be seen that the primary particles of the precursor prepared in Comparative Example 3 are intercalated sheets, but the sphericity and density of the secondary particles are poor.

[0172] Comparing Figure 2 and Figure 5 further proves that the process for preparing the core-shell structure in sections provided by the present application can optimize the morphology of the precursor, reduce the possibility of separate precipitation of zinc, make the overall structure of the precursor more compact, the primary particle sheet more obvious, and improve the sphericity of the precursor.

[0173] Figure 6 The SEM image of the precursor prepared in Comparative Example 4 is shown in FIG. 4. Figure 6 It can be seen that the primary particles of the precursor prepared in Comparative Example 4 are intercalated thick sheets, and the sphericity and compactness of the secondary particles are poor.

[0174] Comparing Figure 2 and Figure 6The inventors speculate that the reason for the poor morphology and tap density of the precursor of Comparative Example 4 is that the content of the doped zinc element in the core is too high, and the excess zinc element is precipitated alone, affecting the sphericity and density of the precursor.

[0175] Figure 7 The SEM image of the precursor prepared for Comparative Example 5 is shown in FIG. 5. Figure 7 It can be seen that the primary particles of the precursor are of a layered structure, and the layered structure is thin, and there is no agglomeration phenomenon. The inventors speculate that the reason for this kind of morphology is that the addition of an antioxidant will cause the sample to be oxidized to a certain extent during preparation, the primary particles become thin, and the tap density decreases.

[0176] The above-described embodiments are merely preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art, within the technical scope of the present application, according to the technical solution and concept of the present application, can make equivalent replacements or changes, which should be covered within the protection scope of the present application.

Claims

1. A sodium-ion battery quaternary precursor, characterized in that, It includes a core and a shell covering at least a portion of the surface of the core; the core has the chemical formula Ni. x1 Zn y1 Fe z1 Mn 1-x1-y1-z1 (OH)₂, wherein 0.1≤x₁≤0.4, 0≤y₁≤0.03, 0.1≤z₁≤0.5, x₁+y₁+z₁<1; the chemical formula of the shell is Ni. x2 Zn y2 Fe z2 Mn 1-x2-y21-z2 (OH)₂, wherein 0.1≤x²≤0.4, 0.04≤y²≤0.12, 0.1≤z²≤0.5, and x²+y²+z²<1; the tap density of the sodium-ion battery quaternary precursor is 1.4~1.8 g / cm³. 3 The primary particles of the sodium-ion battery quaternary precursor are ordered intercalated plates; the secondary particles of the sodium-ion battery quaternary precursor are spherical or near-spherical.

2. A method for preparing a sodium-ion battery quaternary precursor as described in claim 1, characterized in that, Includes the following steps: Step 1: Mix nickel salt, iron salt, manganese salt, zinc salt and the first antioxidant solution to obtain metal salt mixed solution A; mix nickel salt, iron salt, manganese salt, zinc salt and the first antioxidant solution to obtain metal salt mixed solution B; wherein, the zinc salt concentration in metal salt mixed solution B is higher than the zinc salt concentration in solution A. Step 2: Under an inert atmosphere, a metal salt mixed solution A, a precipitant solution, and a complexing agent solution are continuously introduced into the bottom liquid of the reaction vessel to prepare the core. The core preparation includes a first stage and a second stage. The pH value of the reaction system in the first stage is 0.5~1.0 higher than that in the second stage. In the first stage, the pH value of the reaction system is adjusted to 11.0~12.0, and after a certain reaction time, the second stage begins. Then, the pH value of the reaction system is adjusted to 10.5~11.0, and the reaction is carried out for a certain time. Step 3: Stop feeding the metal salt mixed solution A, and continuously feed the metal salt mixed solution B, precipitant solution and complexing agent solution into the bottom liquid of the reaction vessel. Adjust the pH of the reaction system to 9~10, react for a certain time, and obtain the slurry. Step 4: Solid-liquid separation. The slurry obtained in step 3 is then subjected to solid-liquid separation, washing, and drying to obtain the sodium-ion battery quaternary precursor material.

3. A method for preparing a sodium-ion battery quaternary precursor as described in claim 2, characterized in that, After the first stage reaction in step 2 lasts for 28-32 hours or the D50 of the precipitated particles reaches 2.0-2.5 μm, the second stage begins. After the second stage reaction in step 2 lasts for 15-20 hours or the D50 of the precipitated particles reaches 3.0-3.5 μm, the third stage begins. In step 3, the reaction time is 8-12 hours or the D50 of the precipitated particles reaches 3.7-5 μm, and the fourth stage begins.

4. A method for preparing a sodium-ion battery quaternary precursor as described in claim 2, characterized in that, In step 2, the flow rate of metal salt mixed solution A is 30%~90% of the flow rate of metal salt mixed solution B in step 3; the flow rate of metal salt mixed solution A is 80~360 mL / min; in step 3, the flow rate of metal salt mixed solution B is 180~420 mL / min.

5. A method for preparing a sodium-ion battery quaternary precursor as described in claim 2, characterized in that, Nickel salts, iron salts, manganese salts, and zinc salts are each independently one or more of sulfates, nitrates, acetates, and chlorates; The precipitant solution is any one or more of sodium hydroxide solution and potassium hydroxide solution; the concentration of the precipitant solution is 8~12 mol / L. The complexing agent solution is any one or more of sodium citrate solution, sodium fluoride solution, hydroxyethyl ethylenediamine triacetic acid solution, sodium gluconate solution, ethylenediaminetetraacetic acid solution, sodium ethylenediaminetetraacetic acid solution, and ammonia water; the concentration of the complexing agent solution is 4~10 mol / L. The first antioxidant solution is any one or more of ascorbic acid, sodium citrate, and citric acid; the concentration of the first antioxidant solution is 0.15~0.5g / L. In steps 2 and 3, the alkalinity of the reaction system is 5-8 g / L.

6. A method for preparing a sodium-ion battery quaternary precursor as described in claim 2, characterized in that, The bottom liquid of the reaction vessel is prepared from water, a second antioxidant, a precipitant and a complexing agent; the second antioxidant solution is any one or more of hydrazine hydrate solution, hydrazine solution and carbamate solution; the concentration of the second antioxidant in the bottom liquid of the reaction vessel is 0.3~0.8 g / L.

7. A method for preparing a sodium-ion battery quaternary precursor as described in claim 6, characterized in that, The temperature of the bottom liquid in the reaction vessel is 40~60℃, the pH value is 11~12, and the alkalinity is 3.0~9.0g / L.

8. A positive electrode material, characterized in that, The raw materials for the cathode material include the sodium-ion battery quaternary precursor as described in claim 1 or the sodium-ion battery quaternary precursor prepared by any one of claims 2 to 7.

9. A battery, characterized in that, Includes the cathode material as described in claim 8.

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