Multi-element doped ternary precursor and preparation method thereof

文档序号:1848603 发布日期:2021-11-16 浏览:17次 中文

阅读说明:本技术 一种多元素掺杂的三元前驱体及其制备方法 (Multi-element doped ternary precursor and preparation method thereof ) 是由 张宝 邓鹏� 程诚 林可博 周亚楠 丁瑶 于 2021-08-18 设计创作,主要内容包括:本发明涉及前驱体技术领域,具体公开了一种多元素掺杂的三元前驱体及其制备方法,所述前驱体化学式为Ni-(x)Co-(y)Mn-(z)Ti-(p)Br-(q)Na-(w)(OH)-(2)。所述前驱体的制备方法为:将镍盐溶液、锰盐溶液、钴盐溶液、络合剂溶液和沉淀剂溶液分别加入到反应釜中,控制反应参数,根据粒径的不同设定不同的反应阶段,在两个反应釜中分两个阶段进行共沉淀反应,再经洗涤、干燥、混批、过筛、除磁、包装即可得到改性的前驱体。本发明的三元前驱体颗粒均匀、球形度好、粒度分布窄、无微裂纹;本发明制备方法简单易操作,环境污染少,适合大规模工业化生产。(The invention relates to the technical field of precursors, and particularly discloses a multi-element doped ternary precursor and a preparation method thereof, wherein the chemical formula of the precursor is Ni x Co y Mn z Ti p Br q Na w (OH) 2 . The preparation method of the precursor comprises the following steps: respectively adding a nickel salt solution, a manganese salt solution, a cobalt salt solution, a complexing agent solution and a precipitator solution into reaction kettles, controlling reaction parameters, setting different reaction stages according to different particle sizes, carrying out coprecipitation reaction in the two reaction kettles in two stages, and then washing, drying, mixing, screening, demagnetizing and packaging to obtain the modified precursor. The ternary precursor has uniform particles, good sphericity, narrow particle size distribution and no microcrack; the preparation method is simple and easy to operate, has little environmental pollution and is suitable for large-scale industrial production.)

1. A multi-element doped ternary precursor, characterized in that the precursor has the chemical formula: nixCoyMnzTipBrqNaw(OH)2Wherein x, y, z, p, q and w are mole numbers, x is more than or equal to 0.6<1,0<y≤0.2,0<z≤0.2,0<p≤0.08,0<q≤0.05,0<w≤0.05,x+y+z=1。

2. A method of preparing the multi-element doped ternary precursor of claim 1, comprising the steps of:

s1, solution preparation: preparing a metal salt solution A containing nickel ions, cobalt ions, manganese ions, titanium ions, bromide ions and sodium ions; preparing a precipitant solution B; preparing a complexing agent solution C;

s2, first-stage reaction: adding the solution A, the solution B and the solution C into a first reaction kettle for reaction, and controlling reaction parameters: the pH value is 12.1-12.5, the ammonia value is 13-20 g/L, the introduction of the solution B and the solution C is stopped until the D50 particle size of the precursor intermediate is 1-2.5 mu m, and the precursor intermediate slurry is obtained after the reaction is finished;

s3, second-stage reaction: and (4) introducing ammonia water into the second reaction kettle to serve as a base solution, introducing all the precursor intermediate slurry obtained in the step S2 into the second reaction kettle to continue to react, and controlling reaction parameters: the pH value is 11.8-12.4, the ammonia value is 9-12 g/L, and the reaction is completed until the D50 particle size of the precursor particles is 2.5-3 mu m, so that precursor slurry is obtained;

and S4, filtering, washing, drying, mixing, screening, demagnetizing and packaging the precursor slurry obtained in the step S3 to obtain the multi-element doped ternary precursor.

3. The method for preparing the multi-element doped ternary precursor according to claim 2, wherein in step S1, the total ion molar concentration of nickel ions, cobalt ions, manganese ions, titanium ions, bromine ions and sodium ions in the metal salt solution a is 3-10 moL/L.

4. The method for preparing the multi-element doped ternary precursor according to claim 2, wherein in step S1, the precipitant is one or more of sodium hydroxide, potassium hydroxide and sodium carbonate, and the concentration of the precipitant solution is 5-8 mol/L.

5. The method for preparing the multi-element doped ternary precursor according to claim 2, wherein in step S1, the complexing agent is one or more of ammonia water, ammonium sulfate, oxalic acid and ammonium bicarbonate, and the concentration of the complexing agent solution is 6-7 mol/L.

6. The method for preparing the multi-element doped ternary precursor according to any one of claims 2 to 5, wherein in step S1, NiSO is added4·6H2O and TiO2Uniformly mixing solution one, adding CoSO4·7H2Mixing O and NaBr uniformly to obtain solution II, and mixing MnSO4·H2O and TiO2And uniformly mixing the solution A with NaBr to obtain a solution III, wherein the solution I, the solution II and the solution III form the metal salt solution A.

7. The method of claim 2, wherein in step S2, the growth rate of D50 of the precursor intermediate particles is controlled to be 0.1-2 μm/hr.

8. The method according to claim 7, wherein in step S2, the reaction parameters are controlled as follows: the stirring speed is 300-450 rpm, and the reaction temperature is 40-50 ℃.

9. The method of claim 2, wherein in step S3, the growth rate of D50 of the precursor particles is controlled to be 0.1-2 μm/hr.

10. The method for preparing the multi-element doped ternary precursor according to claim 9, wherein in step S3, the reaction parameters are controlled as follows: the stirring speed is 450-550 rpm, and the reaction temperature is 40-50 ℃.

Technical Field

The invention relates to the technical field of precursors, in particular to a multi-element doped ternary precursor and a preparation method thereof.

Background

The ternary precursor is a key material for preparing the ternary positive electrode and is a key link for linking upstream non-ferrous metals (nickel sulfate, cobalt sulfate, manganese sulfate, a front-end smelting and purifying link and the like) and a downstream lithium battery material; the ternary precursor terminal is applied to lithium batteries for new energy automobiles, energy storage and electric tools and 3C electronic products. The performance of the precursor directly determines the main physical and chemical properties of the ternary cathode material, such as particle size, element proportion, impurity content and the like, so that the core electrochemical properties of lithium batteries, such as consistency, energy density, cycle life and the like, are influenced.

The focus of research and development is mostly on modifying the positive electrode material, such as doping and coating, however, the modification (doping or coating) of the positive electrode has the disadvantages of poor uniformity, multiple processes and high energy consumption, and researchers have come to pay attention to the modification of the precursor. Mn (NO) for Zhang Qiyu et al3)2To Ni0.8Co0.1Mn0.1(OH)2The pre-oxidation treatment is carried out, wherein the electrochemical performance of the anode material is also obviously improved, the capacity retention rate is improved from 79.04% to 90.73%, and the alternating current impedance is also greatly reduced.

The doping usually has the phenomenon of non-uniform doping in the sintering process, and the sintering temperature is increased or the sintering process is increased in order to ensure the doping amount and improve the doping uniformity, so that the defects of poor uniformity, high energy consumption and more processes exist. Therefore, in recent years, researchers have been doping elements into the precursor to improve the doping uniformity, reduce the sintering process, and improve the electrochemical performance of the positive electrode material. HE T et al research on ternary high nickel precursor Ni0.8Co0.1Mn0.1(OH)2Outer layer of (3) is doped with Zr in a gradient way4+On the premise of not greatly influencing the capacity of the material, the stability of the material is greatly improved, the cycle and rate performance is also obviously improved, but the capacity retention rate is poorer.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a preparation method of a multi-element doped ternary precursor. The preparation method is simple and reasonable, the cost is low, and the prepared ternary precursor has the advantages of uniform particles, good sphericity, narrow particle size distribution and no microcrack.

It is another object of the present invention to provide a multi-element doped ternary precursor.

In order to realize the purpose of the invention, the concrete scheme is as follows:

a multi-element doped ternary precursor of the formula: nixCoyMnzTipBrqNaw(OH)2Wherein x, y, z, p, q and w are mole numbers, x is more than or equal to 0.6<1,0<y≤0.2,0<z≤0.2,0<p≤0.08,0<q≤0.05,0<w≤0.05,x+y+z=1。

The invention also discloses a preparation method of the multi-element doped ternary precursor, which comprises the following steps:

s1, solution preparation: preparing a metal salt solution A containing nickel ions, cobalt ions, manganese ions, titanium ions, bromide ions and sodium ions; preparing a precipitant solution B; preparing a complexing agent solution C;

s2, first-stage reaction: adding the solution A, the solution B and the solution C into a first reaction kettle for reaction, and controlling reaction parameters: the pH value is 12.1-12.5, the ammonia value is 13-20 g/L, the introduction of the solution B and the solution C is stopped until the D50 particle size of the precursor intermediate is 1-2.5 mu m, and the precursor intermediate slurry is obtained after the reaction is finished;

s3, second-stage reaction: and (4) introducing ammonia water into the second reaction kettle to serve as a base solution, introducing all the precursor intermediate slurry obtained in the step S2 into the second reaction kettle to continue to react, and controlling reaction parameters: the pH value is 11.8-12.4, the ammonia value is 9-12 g/L, and the reaction is completed until the D50 particle size of the precursor particles is 2.5-3 mu m, so that precursor slurry is obtained;

and S4, filtering, washing, drying, mixing, screening, demagnetizing and packaging the precursor slurry obtained in the step S3 to obtain the multi-element doped ternary precursor.

Further, in step S1, the total ion molar concentration of the nickel ions, cobalt ions, manganese ions, titanium ions, bromide ions, and sodium ions in the metal salt solution a is 3 to 10 moL/L.

Further, in step S1, the precipitant is one or more of sodium hydroxide, potassium hydroxide, and sodium carbonate, and the concentration of the precipitant solution is 5 to 8 mol/L.

Further, in step S1, the complexing agent is one or more of ammonia water, ammonium sulfate, oxalic acid, and ammonium bicarbonate, and the concentration of the complexing agent solution is 6 to 7 mol/L.

Further, in step S1, NiSO is added4·6H2O and TiO2Uniformly mixing solution one, adding CoSO4·7H2Mixing O and NaBr uniformly to obtain solution II, and mixing MnSO4·H2O and TiO2And uniformly mixing the solution I, the solution II and the solution III to obtain a metal salt solution A.

Further, in step S2, the solution a, the solution B and the solution C are fed into the first reaction kettle by a metering pump, and the ammonium ion concentration and the pH value of the reaction process are controlled by adjusting the flow rates of the solution B and the solution C.

Further, in the step S2, the total feeding amount of the solution I and the solution II added into the first reaction kettle is 300-500L/h.

Further, in the step S2, the feeding amount of the solution III added into the first reaction kettle is 100-200L/h.

Further, in step S2, the D50 growth rate of the precursor intermediate particles is controlled to be 0.1-2 μm/h.

Further, in step S2, the reaction parameters are controlled: the stirring speed is 300-450 rpm, and the reaction temperature is 40-50 ℃.

Further, in step S3, the D50 growth rate of the precursor particles is controlled to be 0.1-2 μm/h.

Further, in step S3, the reaction parameters are controlled: the stirring speed is 450-550 rpm, and the reaction temperature is 40-50 ℃.

Further, in step S3, the ammonia bottom in the second reaction vesselLimitation of the liquid to hot NH3·H2O。

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention effectively and feasibly modifies the nickel-cobalt-manganese ternary material by adopting a continuous reaction mode that a first reaction kettle is linked with a second reaction kettle, thereby obtaining the multi-element doped ternary precursor. Through the coprecipitation reaction process in the two reaction kettles, the precursor obtained by the invention enables three elements of Ti, Br and Na to be inserted into a ternary crystal lattice, Na doped at the Li position is used as columnar ions to enlarge the spacing of a lithium layer, and Br doped at the O position forms a stronger covalent bond. The co-doping suppresses Li+/Ni2+The mixing of (2) reduces the residual lithium on the surface, stabilizes the crystal structure, improves the ionic conductivity of the material, stabilizes the layered structure, obtains an unprecedented clean surface by doping Ti, has no surface residue, and improves the strength of the oxygen framework. The structural stability of the material is further improved by the coordination of the three elements. The ternary precursor has the advantages of uniform particles, good sphericity, narrow particle size distribution and no microcrack.

(2) The preparation method is simple and easy to operate, has little environmental pollution and is suitable for large-scale industrial production.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention.

FIG. 1 is an SEM image of a precursor obtained in example 1 of the present invention.

FIG. 2 is an SEM image of the precursor obtained in comparative example 1 of the present invention.

Detailed Description

In order to facilitate an understanding of the invention, the invention will now be described more fully and in detail with reference to the accompanying description and preferred embodiments, but the scope of the invention is not limited to the specific embodiments described below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

Example 1

The embodiment provides a preparation method of a multi-element doped ternary precursor, which comprises the following steps:

s1, solution preparation: NiSO of 8.5 moL L was used4·6H2O and 0.01 moL of TiO2Uniformly mixing to obtain solution I and 0.8 moL of CoSO4·7H2O and 0.01 moL of NaBr are evenly mixed to obtain a second solution and 0.7 moL of MnSO4·H2O with 0.01 moL of TiO2And 0.01 moL of NaBr are evenly mixed to obtain a solution III which is prepared by mixing Ni: co: mn: ti: br: molar ratio of Na 0.85: 0.08: 0.07: 0.002: 0.002: 0.002 preparing metal salt mixed solution A, the total ion molar concentration is 5 mol/L; preparing NH with the concentration of 7 mol/L3·H2O solution B; preparing NaOH solution C with the concentration of 4.5 mol/L;

s2, first-stage reaction: feeding the solution A, the solution B and the solution C into a first reaction kettle through a metering pump to react, wherein the flow rate of the solution A is 2.3moL/h, adjusting the flow rates of the solution B and the solution C, and controlling reaction parameters: the pH value is 12.1, the ammonia value is 115g/L, the stirring rotating speed is 350rpm, the reaction temperature is 45 ℃, the D50 growth speed of the precursor intermediate particles in the first reaction kettle is controlled to be 0.4 mu m/h until the D50 particle size of the precursor intermediate is stabilized to be 2 mu m, and the feeding is stopped to obtain precursor intermediate slurry;

s3, second-stage reaction: adding hot dilute ammonia water with the ammonia concentration of 0.3mol/L and the temperature of 50 ℃ into a second reaction kettle according to the volume ratio of 6:1 as a base solution, introducing the precursor intermediate slurry obtained in the step S2 into the second reaction kettle for continuous reaction, and controlling the reaction parameters: the pH value is 12, the ammonia value is 10g/L, the stirring rotating speed is 450rpm, the reaction temperature is 50 ℃, the D50 growth speed of the precursor particles in the second reaction kettle is controlled to be 0.1 mu m/h until the D50 particle size of the precursor particles is stabilized to be 3 mu m, and the feeding is stopped to obtain precursor slurry;

s4, filtering, washing, drying, mixing, screening, demagnetizing and packaging the precursor slurry obtained in the step S3 to obtain the multi-element doped ternary precursor Ni0.85Co0.08Mn0.07Ti0.002Br0.002Na0.002(OH)2

The precursor material obtained in the embodiment is characterized and detected, an electron microscope image of the precursor material is shown in figure 1, the shape of the precursor material is spherical, and the particle size is 2.5-3 μm.

Example 2

The embodiment provides a preparation method of a multi-element doped ternary precursor, which comprises the following steps:

s1, solution preparation: NiSO of 8.5 moL L was used4·6H2O and 0.02 moL of TiO2Uniformly mixing to obtain solution I and 0.8 moL of CoSO4·7H2O and 0.02 moL of NaBr are evenly mixed to obtain a second solution and 0.7 moL of MnSO4·H2And uniformly mixing O, 0.02 moL of TiO2 and 0.02 moL of NaBr to obtain a solution III, wherein the ratio of Ni: co: mn: ti: br: molar ratio of Na 0.85: 0.08: 0.07: 0.004: 0.004: 0.004 preparing a metal salt mixed solution A, wherein the total ion molar concentration is 8 mol/L; (NH) with a concentration of 7 mol/L4)2SO4Solution B; na with the concentration of 4.5 mol/L is prepared2CO3Solution C;

s2, first-stage reaction: feeding the solution A, the solution B and the solution C into a first reaction kettle through a metering pump to react, wherein the flow rate of the solution A is 2.5moL/h, adjusting the flow rates of the solution B and the solution C, and controlling reaction parameters: the pH value is 12.3, the ammonia value is 15g/L, the stirring rotating speed is 400rpm, the reaction temperature is 50 ℃, the D50 growth speed of the precursor intermediate particles in the first reaction kettle is controlled to be 0.35 mu m/h until the D50 particle size of the precursor intermediate is stabilized to be 2 mu m, and the feeding is stopped to obtain precursor intermediate slurry;

s3, second-stage reaction: adding hot dilute ammonia water with the ammonia concentration of 0.3mol/L and the temperature of 50 ℃ into a second reaction kettle according to the volume ratio of 6:1 as a base solution, introducing the precursor intermediate slurry obtained in the step S2 into the second reaction kettle for continuous reaction, and controlling the reaction parameters: the pH value is 12, the ammonia value is 11g/L, the stirring rotating speed is 550rpm, the reaction temperature is 40 ℃, the D50 growth speed of the precursor particles in the second reaction kettle is controlled to be 0.1 mu m/h until the D50 particle size of the precursor particles is stabilized to be 3 mu m, and the feeding is stopped to obtain precursor slurry;

s4, filtering, washing, drying, mixing, screening, demagnetizing and packaging the precursor slurry obtained in the step S3 to obtain the multi-element doped ternary precursor Ni0.85Co0.08Mn0.07Ti0.004Br0.004Na0.004(OH)2

Example 3

The embodiment provides a preparation method of a multi-element doped ternary precursor, which comprises the following steps:

s1, solution preparation: NiSO of 8.5 moL L was used4·6H2O and 0.03 moL of TiO2Uniformly mixing to obtain solution I and 0.8 moL of CoSO4·7H2O and 0.03 moL of NaBr are evenly mixed to obtain a second solution and 0.7 moL of MnSO4·H2And uniformly mixing O, 0.03 moL of TiO2 and 0.03 moL of NaBr to obtain a solution III, wherein the ratio of Ni: co: mn: ti: br: molar ratio of Na 0.85: 0.08: 0.07: 0.006: 0.006: 0.006 preparing a metal salt mixed solution A, wherein the total ion molar concentration is 8 mol/L; (NH) with a concentration of 7 mol/L4)2SO4Solution B; na with the concentration of 4.5 mol/L is prepared2CO3Solution C;

s2, first-stage reaction: feeding the solution A, the solution B and the solution C into a first reaction kettle through a metering pump to react, wherein the flow rate of the solution A is 2.15moL/h, adjusting the flow rates of the solution B and the solution C, and controlling reaction parameters: the pH value is 12.4, the ammonia value is 16g/L, the stirring rotating speed is 400rpm, the reaction temperature is 48 ℃, the D50 growth speed of the precursor intermediate particles in the first reaction kettle is controlled to be 0.35 mu m/h until the D50 particle size of the precursor intermediate is stabilized to be 2 mu m, and the feeding is stopped to obtain precursor intermediate slurry;

s3, second-stage reaction: adding hot dilute ammonia water with the ammonia concentration of 0.3mol/L and the temperature of 50 ℃ into a second reaction kettle according to the volume ratio of 6:1 as a base solution, introducing the precursor intermediate slurry obtained in the step S2 into the second reaction kettle for continuous reaction, and controlling the reaction parameters: the pH value is 12, the ammonia value is 11g/L, the stirring rotating speed is 450rpm, the reaction temperature is 45 ℃, the D50 growth speed of the precursor particles in the second reaction kettle is controlled to be 0.1 mu m/h until the D50 particle size of the precursor particles is stabilized to be 3 mu m, and the feeding is stopped to obtain precursor slurry;

s4, filtering, washing, drying, mixing, screening, demagnetizing and packaging the precursor slurry obtained in the step S3 to obtain the multi-element doped ternary precursor Ni0.85Co0.08Mn0.07Ti0.006Br0.006Na0.006(OH)2

Comparative example 1

The embodiment provides a preparation method of a ternary precursor, which comprises the following steps:

s1, solution preparation: 5moL/L of 8.5 moL of NiSO4·6H2O, 0.8 moL of CoSO4·7H2O, 0.7 moL MnSO4·H2O is uniformly mixed according to the proportion of Ni: co: molar ratio of Mn 0.85: 0.08: 0.07 preparing a metal salt mixed solution A, wherein the total ion molar concentration is 5 mol/L; preparing NH with the concentration of 7 mol/L3·H2O solution B; preparing NaOH solution C with the concentration of 4.5 mol/L;

s2, first-stage reaction: feeding the solution A, the solution B and the solution C into a first reaction kettle through a metering pump to react, wherein the flow rate of the solution A is 2moL/h, adjusting the flow rates of the solution B and the solution C, and controlling reaction parameters: the pH value is 12.1, the ammonia value is 16g/L, the stirring rotating speed is 400rpm, the reaction temperature is 45 ℃, the D50 growth speed of the precursor intermediate particles in the first reaction kettle is controlled to be 0.25 mu m/h until the D50 particle size of the precursor intermediate is stabilized to be 2 mu m, and the feeding is stopped to obtain precursor intermediate slurry;

s3, second-stage reaction: adding hot dilute ammonia water with the ammonia concentration of 0.3mol/L and the temperature of 50 ℃ into a second reaction kettle according to the volume ratio of 6:1 as a base solution, introducing the precursor intermediate slurry obtained in the step S2 into the second reaction kettle for continuous reaction, and controlling the reaction parameters: the pH value is 11.8, the ammonia value is 11g/L, the stirring speed is set to 520rpm, the reaction temperature is 50 ℃, the D50 growth speed of the precursor particles in the second reaction kettle is controlled to be 0.1 mu m/h until the D50 particle size of the precursor particles is stabilized to be 3 mu m, and the feeding is stopped to obtain precursor slurry;

s4, filtering, washing, drying, mixing, screening, demagnetizing and packaging the precursor slurry obtained in the step S3 to obtain a ternary precursor Ni0.85Co0.08Mn0.07(OH)2

The precursor material obtained in the embodiment is characterized and detected, an electron microscope image of the precursor material is shown in fig. 2, the precursor material is irregular spherical, the particle size is 2.5-3 μm, and the particle morphology and the mechanical strength are far inferior to those of a modified group.

In conclusion, the invention obtains a precursor through effective and feasible modification, the ternary precursor has the advantages of uniform particles, good sphericity, narrow particle size distribution and no microcrack, and the preparation method is simple and easy to operate, has little environmental pollution and is suitable for large-scale industrial production.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

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